Analytica doi: 10.3390/analytica7030056

Authors: Jasmina Popović Gordana Petković Sanja Petrović Jelena Zvezdanović Milica Vranić Maja Krstić Ristivojević Đurđa Ivković Ivana Lavadinović

During forest exploitation, large amounts of wood biomass are left as residues after harvesting, even though this material could be valuable in reducing greenhouse gas emissions by replacing fossil fuels and serving as a source of bioactive compounds. Within the context of the European Union’s circular bioeconomy strategy, enhancing the efficacy and rational application of forest logging residues constitutes a critical future objective. To evaluate the possible use of the stumps as forest residue-derived woody biomass for the first time, the chemical composition and presence of bioactive compounds in the xylem and bark of F. angustifolia Vahl. ssp. pannonica Soó & Simon stumps were analyzed, including the content of cellulose, acid-insoluble lignin, acid-soluble lignin, ash, and extractives soluble in toluene–ethanol and hot water. In hot water extracts, total phenolic content, the antioxidant activity determined by scavenging capacity toward DPPH and HPTLC, the content of elements by ICP-OES, and the identification of bioactive compounds by UHPLC-DAD-ESI MS/MS were assessed. Considering the chemical composition, the quality of the xylem of the F. angustifolia (cellulose: 42.46 ± 0.45%; lignin: 25.05 ± 0.02%; hemicelluloses: 19.74 ± 0.46%) was similar to that of the stem. Hot water extracts of the bark of F. angustifolia stumps showed high total phenolic content (33.94 ± 1.43 mg GAE/g DW) and strong antioxidant potential (198.48 ± 3.33 μmol TE/g DW), while toxic metals were not detected. UHPLC-DAD-ESI-MS/MS analysis indicated phenylethanoid glycosides as the dominant compounds in the extracts. The analyzed stumps of Fraxinus angustifolia Vahl. in the “Morović” Forest Administration represent a valuable biomass with potential for further valorization.

Analytica doi: 10.3390/analytica7030055

Authors: Sesona Macanda Hassan Shoyiga Adeniyi Ogunlaja Uliana Pinaeva Sizwe Zamisa Nobathembu Faleni

Mercury contamination in aquatic environments poses significant risks to ecosystems and human health, underscoring the need for effective remediation technologies. This research examines the physicochemical properties of the synthesised polymer materials, and DFT calculations were used as an initial step for material development to validate our experimental outcomes for the prepared polymers: polyaniline (PANI), polyethersulfone (PES), and polyamidoamine (PAMAM). Furthermore, DFT studies were used to elucidate structure–property relationships in polymers, serving as performance predictors for mercury adsorption and selectivity, as well as for their applicability in electronic sensors. The characterisation techniques indicated the high functional group densities of PAMAM dendrimers for effective chelation, while the semi-crystalline structure of PANI improves metal binding. DFT calculations reveal that PAMAM exhibits the smallest HOMO–LUMO energy gap, indicating a high reactivity towards mercury ions. Binding energies indicate that PAMAM forms the most stable single-ion complex; PAM1Hg (0.242 eV, 23.37 kJ mol−1), whereas PES exhibits enhanced interaction at elevated mercury concentrations, resulting in stable multi-Hg complexes, PES3Hg (0.136 eV, 13.13 kJ/mol). The findings indicate that nitrogen-rich functional groups and aromatic systems play a crucial role in mercury binding, highlighting the promise of conductive polymers for creating effective adsorbents aimed at mercury remediation in industrial wastewater.

Analytica doi: 10.3390/analytica7030054

Authors: Hamza Bouakline Mohamed Brahmi Imane Ziani Meryem Idrissi Yahyaoui Alberto Angioni Alessandro Atzei Francesco Corrias Adem Gharsallaoui Abdeslam Asehraou Abdesselam Tahani Ali El Bachiri

Supercritical carbon dioxide extraction (SFE-CO2) is an efficient and environmentally friendly process for extracting bioactive compounds from plant material. This investigation examined the combined effects of air-drying temperature of the leaves and SFE-CO2 operating conditions on the extraction yield, volatile compound composition, and antimicrobial activity of Pistacia lentiscus leaf extracts. Extractions were performed at pressures ranging from 100 to 200 bar and temperatures ranging from 35 to 55 °C. Extraction yield increased with extraction pressure and temperature, while fresh leaves yielded the highest extract, highlighting the importance of pretreatment on extractability. Chemical analysis revealed notable variations in monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, and oxygenated sesquiterpenes depending on drying temperature and extraction parameters, confirming the high sensitivity of the volatile compound composition to processing conditions. Response surface methodology (RSM) was used to optimize process variables in order to enhance antimicrobial activity. The extracts inhibited both bacterial and fungal strains, confirming that the extraction conditions exert a direct influence on biological properties. The quadratic model identified the optimal combinations of drying and supercritical CO2 extraction parameters, thereby providing a rational strategy to maximize the antimicrobial potency of P. lentiscus extracts. Overall, controlling pretreatment and supercritical extraction conditions allows for targeted modulation of chemical composition and bioactivity, thereby promoting the development of natural antimicrobial agents and valuable functional components.

Analytica doi: 10.3390/analytica7030053

Authors: Aziz Soulaimani Mohamed El Gharous Khalil El Mejahed Mohamed Louay Metougui Reda Oulfakir Latifa Hajji Said Gmouh

Reliable determination of macro- and micronutrients in cereal plant tissues is essential for agronomic management, environmental monitoring, and interlaboratory data comparability. However, most existing plant certified reference materials (CRMs) are derived from temperate-region matrices and do not adequately represent cereals cultivated under semi-arid conditions, where differences in mineral composition may lead to matrix-related analytical bias. In this study, a new multi-element plant reference material, Cereal Plant Powder 2023 (CPP-23), was developed from composite wheat (Triticum aestivum and T. durum) samples collected across major Moroccan agro-ecological zones. The material was processed, homogenized, and evaluated for homogeneity and stability in accordance with ISO 33405:2024, with no significant short- or long-term variability observed. Elemental characterization was performed using microwave-assisted acid digestion followed by ICP-OES for major and trace elements, while total nitrogen was determined using the Kjeldahl method. Method validation demonstrated satisfactory linearity (R2 > 0.995), precision, and trueness against established reference materials. Certified values were assigned through an interlaboratory comparison involving eight ISO/IEC 17025-accredited laboratories using robust statistical estimators (ISO 13528:2022). Expanded uncertainties (k = 2) were below 15% for all analytes. While these results indicate acceptable internal consistency, the relatively limited number of participating laboratories and the absence of independent analytical validation techniques represent important constraints. CPP-23 provides a matrix-representative material suitable for quality control and method validation in semi-arid agricultural systems. Nevertheless, its ability to reduce analytical bias relative to existing CRMs and its applicability to specific use cases require further experimental validation.

Analytica doi: 10.3390/analytica7030052

Authors: Fotouh R. Mansour Khalid M. Omer Sameera Sh. Mohammed Ameen Marcello Locatelli Imran Ali Alaa Bedair

The evaluation of analytical methods has evolved beyond traditional validation parameters to encompass environmental sustainability, analytical reliability, and practical applicability. While numerous assessment tools exist for individual dimensions, integrated multicolor frameworks often impose rigid parameter selection, assign equal weights to all dimensions regardless of analytical context, or lack the granular diagnostic feedback necessary for method improvement. To address these limitations, we present the Triple-Color Assessment (TriCA) tool, a web-based platform that integrates three validated metrics into a unified scoring system with a hierarchical weighting scheme. TriCA combines the Analytical Green Star Area (AGSA) for greenness assessment, the Click Analytical Chemistry Index (CACI) for blueness evaluation, and the Analytical Method Reliability Index (AMRI) for redness scoring. While these metrics are provided as defaults, users may select alternative assessment tools within each dimension according to their specific preferences or requirements. TriCA features a user-customizable weighting system with recommended defaults (red = 3, blue = 2, green = 1), reflecting the logical priority that a method must first be valid, then practical, and finally green. Users can adjust these weights for specific contexts, while the underlying metric scoring protocols (AGSA, CACI, and AMRI) remain fixed to ensure reproducibility. Beyond composite scoring, TriCA generates three detailed pictograms, 12 segments for AGSA, eight segments for CACI, and 10 segments for AMRI, each color-coded to show performance at the individual criterion level. This diagnostic capability enables analysts to identify exactly which green chemistry principles, practicality criteria, or validation parameters are deficient, transforming assessment from an opaque scoring exercise into actionable guidance for method improvement. Seven case studies encompassing diverse analytical techniques demonstrate TriCA’s discriminative power and diagnostic utility. The tool is freely accessible at bit.ly/TriCA, offering the analytical community a transparent, reproducible, and diagnostically rich framework for method evaluation, development, and optimization.

Analytica doi: 10.3390/analytica7030051

Authors: Rodrigo E. Dominguez Valerie Yang Ashley Fu Edward H. Cheng Mirna Terrera Piyush Hota Ayushi Pradhan Sandra Miranda Christine Snozek Leslie Thomas Mary Laura Lind Thomas Fang Chen Erica Forzani

Urinary urea is a key biomarker for tracking protein oxidation and nitrogen balance. A persistent analytical limitation is that conventional total-nitrogen assays do not deconvolute urinary urea from urinary ammonia, and direct measurement still requires capital-intensive clinical analyzers. Here, we implement and independently validate two cost-effective methods that resolve urinary urea by pairing the presence and absence of urease: Method 1 is a urease-coupled potentiometric assay using an ammonium ion-selective electrode (ISE method); Method 2 is a microplate Berthelot–salicylate colorimetric assay employing a repurposed consumer-grade aquarium ammonia test kit (API®) (API method). Each method was validated against the Roche Cobas C311 clinical analyzer (ISE for urinary ammonia and API for urinary urea) in healthy adult volunteers (n = 10 each), and API–ISE were then compared head-to-head for urinary urea. ISE vs. Cobas yielded R2 = 0.967, slope 95% CI [0.867, 1.173], and Bland–Altman bias of −1.02 mM (95% LoA [−7.40, +5.36] mM). API vs. Cobas yielded R2 = 0.973, slope 95% CI [0.790, 1.039], and bias of −1.55 mM (95% LoA [−11.56, +8.46] mM). API–ISE urinary urea comparison confirmed mutual agreement (R2 = 0.9976, slope 95% CI [0.946, 1.024]; bias of +3.47 mM; 95% LoA [−14.60, +21.53] mM), with mean recoveries near 100% (API: 100.7 ± 2.9%; ISE: 100.6 ± 5.4%; 20–350 mM). Both methods agreed with the clinical analyzer, supporting their potential for decentralized, resource-limited testing; clinical and point-of-care validations are needed.

Analytica doi: 10.3390/analytica7030050

Authors: Dmitry Chistyakov Andrey Samokhin Vladislav Gorbatenko Vasiliy Vasil’ev Maksim Donnikov Anna Morozkina Tatiana Sinyukova Lyudmila Kovalenko Marina Sergeeva

Metabolomic aging clocks—quantitative models that estimate biological age based on small-molecule profiles in biological fluids—have become dynamic tools for assessing individual aging trajectories and predicting the risk of age-related diseases. Although NMR-based approaches have been previously reviewed, the analytical landscape of mass spectrometry (MS)-based metabolomic clocks has not been systematically assessed. This review examines the key components of the MS-based analytical workflow underlying the development of metabolomic aging clocks, including biological matrix selection, chromatographic separation strategies, MS instrumentation, data preprocessing, metabolite annotation, and machine learning-based modeling approaches. Twelve published studies on MS-based metabolomic clocks were identified and systematically compared. These clocks provide predictions of chronological age with mean absolute errors of 3.5–10 years and demonstrate robust associations between metabolomic age acceleration and cardiometabolic risk, frailty, and mortality. Recurrent age-related metabolite classes include tryptophan–kynurenine pathway metabolites, acylcarnitines, sphingolipids, modified nucleosides, and tricarboxylic acid (TCA) cycle intermediates. Currently, liquid chromatography with electrospray ionization (LC-ESI) coupled to high-resolution QTOF or Orbitrap instruments dominates current workflows, with elastic net regression being the most commonly applied modeling strategy. Significant heterogeneity in analytical conditions, incomplete methodological descriptions, and limited cross-study validation remain key obstacles to clinical application. Standardization of pre-analytical protocols, the use of certified reference materials, and harmonized validation frameworks are identified as critical priorities for advancing mass spectrometry-based metabolomic clocks toward clinical translation.

Analytica doi: 10.3390/analytica7030049

Authors: David Encinas-Basurto Jorge Márquez-Escalante Karla G. Martínez-Robinson Alma C. Campa-Mada Refugio Pérez-González Elizabeth Carvajal-Millan

Sulfated polysaccharides from red algae are multifunctional hydrocolloids whose properties depend strongly on molecular structure, sulfate content, and chain conformation. In this study, a sulfated galactan extracted from Gracilaria vermiculophylla collected from a coastal region of northwestern Mexico was investigated to elucidate its structural and functional properties. The polysaccharide was extracted by enzymatic treatment and characterized by monosaccharide analysis, FTIR, 1D/2D NMR spectroscopy, and size-exclusion chromatography coupled with multi-angle light scattering and viscometry. The extracted polysaccharide exhibited high carbohydrate (97%) and sulfate (28%) contents, with galactose as the predominant monosaccharide. It showed a moderate molecular weight (Mw = 2.39 × 105 g/mol), a relatively narrow molar mass distribution (Mw/Mn = 1.23), a high intrinsic viscosity (420.9 mL/g), and an Rg/Rh ratio of 2.2, consistent with an expanded macromolecular conformation in solution. The sulfated polysaccharide also exhibited measurable antioxidant activity, particularly in the ABTS+ assay (IC50 = 31.8 ± 2.5 mg/mL) compared with the DPPH assay (IC50 = 51.1 ± 3.0 mg/mL), and showed Fe3+-responsive association, leading to the formation of microgel-like structures. These findings indicate that the sulfated galactan characterized in this study is a structurally complex and functionally active hydrocolloid with potential relevance for functional food systems and related biomaterial applications.

Analytica doi: 10.3390/analytica7030048

Authors: Kamilla Molli Vincze Evelin Szolnoki-Suhajda Arash Mirzahosseini Péter Horváth György Tibor Balogh Tamás Pálla

Serum albumin binding plays a critical role in determining the pharmacokinetic and pharmacodynamic behavior of many drugs. Despite extensive studies on human and bovine serum albumin, quantitative binding data for rabbit serum albumin remain limited for several therapeutically important compounds. In this study, the binding interactions of three oxicam-class non-steroidal anti-inflammatory drugs (meloxicam, tenoxicam, and piroxicam) with rabbit serum albumin were investigated using circular dichroism spectroscopy and fluorescence quenching measurements. Binding parameters were estimated using nonlinear mixed-effects models that simultaneously incorporated data from multiple spectral channels and experimental replicates while accounting for residual correlation and heteroscedastic variance. Fluorescence-based analyses produced estimates consistent with the combined models and showed substantially lower uncertainty compared with CD-only analyses. These findings demonstrate that fluorescence quenching provides more reliable quantitative estimates of albumin binding affinity, whereas CD measurements exhibit higher variability in this context. The results represent the first systematic report of oxicams binding to rabbit serum albumin, with stability constants of meloxicam (logK = 4.840 ± 0.009), piroxicam (logK = 5.068 ± 0.007 and tenoxicam (logK = 4.668 ± 0.004) and highlight the importance of experimental determination of binding parameters even within closely related drug classes. The modeling framework employed here provides a robust statistical approach for analyzing spectroscopic titration data and may be broadly applicable to studies of drug–protein interactions.

Analytica doi: 10.3390/analytica7030047

Authors: Justyna Grabska Krzysztof B. Bec Vanessa Moll Anna Fiegl-Lechner Christian W. Huck

Synthetic azo dyes may be fraudulently added to paprika powder to intensify color, creating a need for rapid, at-line screening before confirmatory chromatographic analysis. This study evaluated handheld laser-induced breakdown spectroscopy (LIBS) for the screening of sodium-salt azo dye adulteration represented by Allura Red (E129), Ponceau 4R (E124), and Orange II in paprika powder. Paprika was spiked at 17 levels (0–6% w/w) in three independent batches, mixed with Al2O3 binder, dried, pelletized, and measured with a portable SciAps Z-903 under argon in the broad 190–950 nm region. The calibration models were developed using SNV-pretreated spectra and partial least squares regression with test-set validation based on a 70/30 split by concentration level. The main concentration-related response was increased Na emission, consistent with the sodium-salt form of the dyes, while Al emission showed an inverse matrix-/plasma-coupled trend despite the constant binder fraction. Full-spectrum models gave R2TSV values of 0.845–0.875 and RMSETSV values of 0.638–0.716% (w/w), using 4–5 latent variables. Outlier trimming improved prediction for Allura Red and Orange II, while regression coefficient-uncertainty variable selection reduced model complexity to 2–3 latent variables with dye-dependent effects. Since sodium-salt azo dyes are commonly used as adulterants in paprika powder, the Na-dominated LIBS response demonstrates good potential for rapid at-line screening. Nevertheless, as LIBS does not directly confirm dye identity, complementary confirmatory analysis using spectroscopic or chromatographic methods remains necessary.

Analytica doi: 10.3390/analytica7030046

Authors: Geovani Moreira da Cruz Raquel Teles de Menezes Lara Steffany de Carvalho Tuana Mendonça Faria Cintra Gabriela Torres Tediole Paula dos Santos Avelino Maria Cristina Marcucci Luciane Dias de Oliveira Vanessa Marques Meccatti-Domiciano

Candida spp. can cause systemic infections with high mortality in immunocompromised patients. Phytotherapy may be an alternative for adjunctive treatment of fungal infections. This study evaluated the phytochemical profile, cytotoxicity, genotoxicity, and antibiofilm activity of the hydroalcoholic extract of Origanum vulgare L. against Candida albicans, Candida tropicalis, and Candida dubliniensis. The extraction and quantification (flavonoids and phenols) were performed, and its antioxidant activity (DPPH) and the presence of bio-active compounds were investigated using high-performance liquid chromatography with Diode Array Detection (HPLC-DAD). Cytotoxicity and genotoxicity tests were conducted using HaCat cell lines. Antifungal activity on planktonic cultures was evaluated using the standard (CLSI M27-S4). The analysis of the extract on biofilms was verified with different exposure times. The extract demonstrated the presence of bioactive molecules, and antioxidant activity. The cytotoxicity test showed viability >70%. Genotoxicity revealed the presence of a few micronuclei in some dilutions. The Minimum Fungicidal Concentration was obtained for C. albicans and C. tropicalis. In the biofilm analysis, there was a reduction of more than 60% in all Candida spp. species at the 24 h exposure time. The findings suggest that the O. vulgare extract exhibits activity against Candida spp. and shows biocompatibility in human keratinocytes.

Analytica doi: 10.3390/analytica7030045

Authors: Meryem Dafir Najoua Labjar Souad El Hajjaji

This study developed and validated a modified QuEChERS extraction procedure for the determination of 32 pesticide residues in tea (Camellia sinensis) found in Moroccan market originating from China and rosemary (Salvia rosmarinus) leaves using UPLC-MS/MS. A total of 202 pesticide residues were initially screened using the NF EN 15662 method, and 32 compounds showed satisfactory recovery and precision in tea. The optimized method, based on freezing before extraction and using PSA + BCG as purification sorbents, achieved recoveries of 70–120% for 97% of analytes. Calibration linearity ranged from 0.001 to 0.2 mg/kg (R2 ≥ 0.980), with spiking levels at 0.01–0.1 mg/kg analyzed in duplicate per level and per matrix. Results of LOQ and LOD are compared to multiple MRL databases of Tea (EU, USA, Canada, Codex Alimentarius) despite the scarcity of tea MRLs in most databases, providing an accurate representation of the complexity of the analysis. Uncertainty was evaluated through both validation-based and Horwitz-based approaches, allowing a robust comparison of theoretical and experimental variability. The optimized method was also applied to rosemary, where 31 of the 32 pesticides validated in tea showed satisfactory performance. Similar recoveries, precision, and LOQs were obtained for both matrices, demonstrating the robustness of the method across chemically diverse herbal substrates. Only carbofuran exhibited reduced performance in rosemary, requiring an increased functional LOQ because of matrix-induced ion suppression. This dual-matrix approach provides a reliable and reproducible method for pesticide monitoring in herbal products. This dual-matrix approach provides a reliable and reproducible method for pesticide monitoring in herbal products.

Analytica doi: 10.3390/analytica7030044

Authors: Miryam Chiara Malacarne Manuela Loiacono Simone Conti Enrico Caruso

The utilisation of cosmetic plant waxes as sustainable functional ingredients in personal care formulations is on the rise. This is due to their emollient, structuring and film-forming properties. Nevertheless, the intricate lipid composition of these substances engenders considerable analytical difficulties, impeding the reliable characterisation and quality assessment thereof. In this study, an optimised gas chromatography–mass spectrometry (GC–MS) workflow was developed and evaluated for the compositional profiling of waxes derived from R. succedanea and R. verniciflua, two East Asian botanical species that have historically been utilised in cosmetic and lacquer-related applications. Wax samples originating from China, Vietnam, Korea, and Japan were extracted using solvents of different polarity, including petroleum ether, dichloromethane (DCM), ethyl acetate, and acetone. Following the process of BSTFA derivatisation, the extracts were subjected to analysis by GC–MS to evaluate the efficiency of the extraction process and the chemical composition of the extracts. DCM was found to provide the highest extraction yields and the most representative compositional profiles. Across all samples, palmitic acid was identified as the predominant constituent (80–90%), followed by lower amounts of oleic acid, stearic acid, and minor monoacylglycerols. The proposed analytical workflow exhibited satisfactory reproducibility and effective discrimination of lipid constituents, thereby substantiating its application in comparative compositional evaluation, potential support for future quality assessment studies, and formulation development of cosmetic plant waxes.

Analytica doi: 10.3390/analytica7020043

Authors: David Pickup J. Beau W. Webber

This article describes the development of a compact and affordable variable-temperature NMR instrument designed primarily to measure dynamic molecular motion in solids and liquids. The instrument consists of Lab-Tools’ Mk4 palm-top time-domain NMR spectrometer fitted with a Peltier-cooled variable-temperature probe inside a shimmed Halbach magnet. Measurement of NMR relaxation times T1, T2, and T1ρ is possible over the temperature range −20 °C to 70 °C with cooling and heating rates, and data acquisition is controlled from an integrated mini-PC. The overall footprint of the instrument is roughly that of a shoe box, making both in-the-field and bench-top measurements possible. Applications of this instrument include measuring pore-size distribution in porous rocks, the viscosity of oils and tars trapped in porous rock, the properties of polymers, and the viscosity of the liquid components of foods (e.g. fruits, vegetables and seeds). Results of test measurements for calibrated oils and olive oil are presented together with measurements of molecular mobility in a solid polymer.

Analytica doi: 10.3390/analytica7020042

Authors: Jevrem Stojanović Huseinatu Osman Ana Protić Anđelija Malenović Mira Zečević Biljana Otašević Nataša Avramović

Spectrophotometry offers the advantage of low cost and less time consumption, making it still attractive as a method of analysis, especially when coupled with multivariate calibration models. This enhancement solves the majority of the drawbacks of UV–VIS spectrophotometry, which have to do with the entangled spectra of complex mixtures. In this study, a multivariate model was developed and validated for the determination of perindopril erbumine, amlodipine besylate and indapamide, addressing previously unresolved challenges by systematically covering three fixed-dose combinations with differing component ratios and by achieving accuracy suitable for the assay determination. The experimental plan involved a Taguchi orthogonal array design with three factors at five levels. In order to create multivariate calibration models, principal component regression, partial least squares and concentration residual augmented least squares regression algorithms were tested. Principal component regression combined with a genetic algorithm for feature selection was chosen as the optimal model based on prediction performance estimated by nested cross-validation with cluster-based sample splitting. The developed method was also evaluated for its environmentally friendly potential while the analytical method validation procedure confirmed its applicability for the assay testing of the fixed-dose drug combination.

Analytica doi: 10.3390/analytica7020041

Authors: Paola Peralta Rodrigo Ortega-Toro Joaquín Hernández-Fernández

Oxalic acid is extensively used in industrial chemical processes, purification systems, hydrometallurgical operations, and advanced oxidation environments where rapid and environmentally sustainable analytical methodologies are increasingly required for process monitoring and quality control. In this study, a micro-Raman spectroscopy methodology was developed for the direct quantification of oxalic acid in aqueous systems at moderate-to-high concentrations (0.079–0.793 M). The analytical strategy was based on the integrated Raman response of the carbonyl stretching region (1700–1750 cm−1), selected due to its strong concentration-dependent behavior, spectral definition, and reduced interference from the aqueous matrix. The proposed methodology demonstrated excellent analytical performance, including high linearity (R2 > 0.998), satisfactory precision, and reliable concentration-dependent reproducibility throughout the evaluated concentration range. To evaluate operational robustness, matrix-matched standards incorporating temperature variation (25–40 °C), turbidity (0–57 mg/L), dissolved Ca2+ (0–58 mg/L), and dissolved Fe3+ (0–7 mg/L) were prepared to simulate chemically perturbed industrial environments. Principal Component Analysis (PCA) demonstrated that the carbonyl vibrational region retained organized concentration-dependent spectral behavior despite operational perturbations. Partial Least Squares (PLS) regression models developed under these matrix-informed conditions preserved strong predictive capability (R2 ≈ 0.997), while preliminary prediction of process-related samples yielded excellent agreement between predicted and reference concentrations (R2 = 0.990). Although operational perturbations produced substantial attenuation of Raman intensity, particularly at lower concentration levels, the carbonyl Raman band remained spectrally detectable and analytically interpretable throughout all evaluated conditions. Electronic-structure analysis using Natural Bond Orbital (NBO) and Atoms-in-Molecules (AIM) methodologies demonstrated that the strong analytical behavior of the ν(C=O) vibrational mode is associated with enhanced electron-density localization, covalent stabilization, and favorable polarizability characteristics of the carbonyl bond. The combined experimental, chemometric, and computational results demonstrate the feasibility of matrix-informed micro-Raman spectroscopy as a rapid, reagent-free, and operationally robust methodology for oxalic acid monitoring in chemically perturbed aqueous industrial systems.

Analytica doi: 10.3390/analytica7020039

Authors: Pedro A. Granados Livia L. Sa-Barreto Tais Gratieri Guilherme M. Gelfuso Idejan P. Gross Marcilio Cunha-Filho

Hot-melt extrusion (HME) is widely used in pharmaceutical manufacturing; however, reliable analytical tools are required to simultaneously monitor drug content and excipient stability under thermal processing. In this study, a selective and robust HPLC–UV method was developed and validated for the concurrent determination of triamcinolone acetonide (TA) and triethyl citrate (TEC) in HME polymeric films and porcine buccal mucosa. Chromatographic separation was achieved on a C18 column using an acetonitrile–water mobile phase (30:70, v/v) at a flow rate of 0.6 mL min−1, with detection at 240 nm for TA and 210 nm for TEC. The method was validated for selectivity, linearity, precision, and accuracy, including selectivity assessment in the presence of mucosal extract and polymeric matrix components, and recovery of TA in porcine buccal mucosa. Excellent linearity was obtained over 0.20–12.5 µg mL−1 for TA and 4.5–30.0 µg mL−1 for TEC (r ≥ 0.998), with precision below 6.3% and TA recovery exceeding 94%. Application to extruded films confirmed uniform analyte distribution and enabled simultaneous monitoring of TA degradation and TEC loss under thermal stress. These results demonstrate that the proposed method is suitable for formulation development, process monitoring, and stability assessment of HME-based pharmaceutical systems.

Analytica doi: 10.3390/analytica7020040

Authors: Ljuboš Ušjak Krystyna Skalicka-Woźniak Łukasz Kulinowski Łukasz Świątek Kinga Salwa Izabela Korona-Glowniak Katarzyna Suśniak Marjan Niketić Silvana Petrović

The chemical composition and bioactivities of dry methanol extracts from roots, leaves and fruits of Prangos trifida (Apiaceae), collected in Serbia, were investigated. LC-DAD-QTOF-MS/MS analysis revealed 30 compounds, primarily polyphenols and coumarins. The root and leaf extracts were rich in chlorogenic and/or 3,5-di-O-caffeoylquinic acid (18.20–26.14 mg/g extract), and the fruit extract in oxypeucedanin hydrate and prantschimgin (46.50 and 71.64 mg/g). The leaf extract exhibited the highest total phenolic content (62.86 mg quercetin equivalents/g), total antioxidant activity (FRAP = 0.71 mmol Fe2+/g) and DPPH radical scavenging ability (44.08 mg quercetin equivalents/g). Antimicrobial activity testing (11 bacteria and three yeasts, microdilution method) showed that the most active were the root and leaf extracts against Micrococcus luteus, Staphylococcus aureus, S. epidermidis and Candida albicans (MIC = 0.625–5 mg/mL). The fruit extract showed the strongest cytotoxicity against tested stomach, colon and hypopharynx cancer cell lines (MTT test), with the highest selectivity toward hypopharynx cancer FaDu cells (selectivity index 4.71; determined in relation to non-cancerous VERO cells). No antiviral activity against herpesvirus type 1 was found. The results indicate that P. trifida represents a promising source of polyphenols and coumarins, notably expanding current knowledge on its chemical composition and supporting its potential relevance for pharmaceutical and food industry applications.

Analytica doi: 10.3390/analytica7020038

Authors: Maria Chiara Frondaroli Chiara Fanali Nina Felli Salvatore Fanali

The separation of chiral compounds is a challenging issue in various fields, e.g., biochemistry, the pharmaceutical industry, food chemistry, forensics, agriculture, etc. Very often, one of the two enantiomers can exhibit different activity. Therefore, the separation and analysis of enantiomers requires analytical methods for, e.g., quality control, pharmacokinetic studies, etc. Their separation is usually performed by high-performance liquid chromatography (HPLC), gas chromatography, supercritical fluid chromatography and microfluidic techniques such as capillary electrophoresis (CE), nano-liquid chromatography, and capillary electrochromatography (CEC). CEC is a modern analytical technique that combines the features of HPLC and CE (high selectivity and high chromatographic efficiency, respectively). The enantiomers are moved to the detector by an electroosmotic flow generated by the application of high voltage. In this review, the main features of CEC, and the basic principles of enantiomer separation are briefly summarized. Selected applications (appearing 2023–2026 February) employing packed capillaries, and monolithic and open tubular columns, are presented and discussed.

Analytica doi: 10.3390/analytica7020037

Authors: Tatiana S. Kolesnikova Marina O. Gorbunova Igor E. Uflyand Vladimir A. Zhinzhilo Anastasiya O. Zarubina Vadim A. Volochaev

The paper describes the preparation of silver-containing nanocomposites by thermolysis of silver cinnamate and their application for the manufacture of reactive indicator paper (RIP) sensitive to iodine. The composition, structure, and properties of the obtained materials were studied using IR spectroscopy, X-ray diffraction, the gravimetric analysis method, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Optimal conditions for modifying a cellulose carrier with nanocomposites in laboratory conditions were selected, ensuring high sensitivity of RIP to iodine and uniform and reproducible distribution of the reagent. A new gas extraction colorimetric technique for determining iodide ions in the range of 0.03–1.6 mg L−1 (limit of detection 0.01 mg L−1) was developed, allowing iodides to be determined in multicomponent objects such as food products, pharmaceuticals, and various water bodies with minimized sample preparation. The use of iron(III) as an oxidizing agent and the use of dynamic gas extraction ensure high selectivity and good analytical performance.

Analytica doi: 10.3390/analytica7020036

Authors: Rosita Cappai Clemente Bretti Sofia Gama Concetta De Stefano Demetrio Milea

Despite its widespread use in pharmaceuticals, cosmetics, and animal nutrition, the environmental implications of nicotinamide remain largely underexplored. Given its high solubility and prevalent presence in wastewaters, nicotinamide has been proposed as a potential environmental marker and emerging contaminant. This study focuses on the evaluation and modeling of medium and ionic strength effects on the acid-base behavior of nicotinamide in aqueous solution. To this aim, the protonation constants of nicotinamide were determined in aqueous media containing various supporting electrolytes (sodium chloride, tetramethylammonium chloride, tetraethylammonium iodide) at T = 298.15 K and different ionic strengths. The medium and ionic strength dependencies were described through well-established thermodynamic models, including the Extended Debye–Hückel equation, the Specific ion Interaction Theory, and the Pitzer approach. Additionally, the Setschenow constant of nicotinamide was determined through distribution measurements between 1-octanol and NaCl(aq) solutions. Furthermore, a critical data analysis was performed to assess the reliability of the proposed models and provided interaction parameters. Overall, this work thoroughly describes the acid-base behavior of nicotinamide in different aqueous media and its distribution between aqueous and organic phases, offering fundamental insights for the assessment of its chemical speciation in real systems, which is crucial for future applications in environmental monitoring and remediation strategies.

Analytica doi: 10.3390/analytica7020035

Authors: Ye Rin Jin Heung Joo Yuk Dong-Seon Kim

Comparative interpretation of antioxidant activity across complex natural-product extracts and multi-component formulations is often limited by heterogeneous endpoints, assay-specific reporting, and incompatible units. In this study, we establish a dimensionless Effect Factor (EF) framework as a standardized comparative indexing system for matched-condition comparison of antioxidant-related readouts. EF maps four widely used antioxidant-related readouts—ABTS, DPPH, total phenolic content (TPC), and total flavonoid content (TFC)—into a common dimensionless index space while preserving endpoint meaning through two complementary tracks: potency-type EF and content-type EF. Using a standardized extraction and assay pipeline, we generated EF indices for 586 extracts prepared under water and 30% ethanol conditions and organized them into EF-indexed databases. EF is not intended as a predictive or biologically validated efficacy metric, but as a standardized comparative indexing framework that enables reproducible benchmarking, database-level referencing, and structured interpretation of heterogeneous antioxidant-related data under harmonized experimental conditions. These results establish the EF-indexed resource as a scalable and expandable comparative infrastructure for natural-product research.

Analytica doi: 10.3390/analytica7020034

Authors: Aurélie Urbain Yohan Paille Maria Meidani Yaouba Souaibou Lucile Berthomier César Cotte Valérie Bardot

Arachidonate 5-lipoxygenase (ALOX5) is a key enzyme implicated in several inflammatory disorders, including asthma and allergic rhinitis. Despite its therapeutic importance, only one compound is currently approved as an ALOX5 inhibitor in the United States, highlighting the urgent need for new drug candidates. Progress in this area is often hindered by conventional bioassays, which can be labor-intensive, costly, and unsuitable for complex mixtures. To overcome these challenges, we developed a simple thin-layer chromatography (TLC) bioautographic assay for the rapid detection of ALOX5 inhibitors in natural extracts, a rich source of pharmacologically active compounds. The method exploits the oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone (MBTH) with 3-(dimethylamino)benzoic acid (DMAB) during the ALOX5-catalyzed conversion of arachidonic acid, producing a colored indamine dye. Experimental parameters influencing chromogenic reaction were investigated and optimized to minimize reagent consumption while ensuring accuracy and sensitivity of the method. The assay was then applied to a panel of natural products and to crude mushroom extracts, enabling the rapid identification of several active compounds within complex extracts, including the dual COX2/ALOX5 inhibitor 3α-acetylpolyporenic acid A. Easy to implement, cost-efficient, and well suited for screening and bioguided fractionation, this TLC bioassay provides a powerful tool to accelerate the discovery of novel anti-inflammatory compounds.

Analytica doi: 10.3390/analytica7020033

Authors: Iran Ocaña-Rios Vanessa-Estafania Miranda-Gómez Vicente Esquivel-Peña Jerónimo Cabrera-Peralta Abigail Medina-Miranda Luis-Angel Ojeda-Gomez José de Jesús Olmos-Espejel

This paper describes a simple and sensitive method for determining the content of five bisphenols at the µg L−1 level in tea infusion samples. The procedure uses a polypropylene hollow fiber filled with a deep eutectic solvent as the acceptor phase and 1-octanol as the supported liquid membrane, and the optimal conditions for the three-phase stir bar microextraction method were established as follows: a menthol–octanoic acid mixture (1:1 molar ratio) as the hollow-fiber filling, an extraction time of 1 h, and 80 µL of methanol for analyte desorption. The method demonstrated good linearity over the ranges of 1.5–30.0 µg L−1 (BPF, BPA, BPAF, and BADGE) and 6.0–120.0 µg L−1 (BPZ), with limits of detection between 0.28 and 1.01 µg L−1, and the relative recovery values were satisfactory (99–120%) with acceptable precision (RSD < 17%). Thus, the method was successfully applied to quantitatively analyze twenty commercial tea infusions, in which BPF was detected at concentrations above the LOQ, and the greenness and overall applicability of the approach were confirmed using the AGREEprep and BAGI assessment tools.

Analytica doi: 10.3390/analytica7020032

Authors: Vladimir V. Poborchii Dmitrij Rappoport

We studied experimentally and computationally the structures and optical properties of sulfur (S), selenium (Se) and tellurium (Te) ring clusters. We encapsulated S, Se and Te into AFI, MOR, CHA and LTA zeolites via vapor adsorption or high-pressure injection from melt and studied Raman and optical absorption spectra (RS and OAS, respectively) of zeolite single crystals with incorporated S, Se and Te ring clusters. Importantly, strict orientation of the rings in zeolite crystals allowed us to study the polarization/orientation dependency of ring RS and OAS. The obtained experimental spectra are found to be in agreement with density functional theory results (DFT using the PBE0 functional and def2-TZVP basis sets) for S8, Se6, Se8, Se12, Te6 and Te8 ring molecules. The agreement is especially good for Te rings, while for S and Se rings harmonic frequency scaling factors are required. The S and Se rings display light-induced effects, which we attribute to the presence of conical intersections between their ground and excited electronic states, resulting in isomerization and subsequent fragmentation. We consider this effect using the Se6 ring example. This phenomenon is important for understanding photostructural changes not only in chalcogen clusters but also in bulk materials such as amorphous selenium.

Analytica doi: 10.3390/analytica7020031

Authors: Virginia G. Correia Victor F. Jesus Rodolfo S. Barboza Alviclér Magalhães Leonardo N. Seito Mário Gomes Marcelo R. R. Tappin Ligia M. M. Valente

The species Psychotria densicostata Müll.Arg. is a shrub belonging to the Rubiaceae family, endemic to Brazil. So far, there are reports neither of phytochemical work on nor of biological evaluation of it. This study investigated its alkaloid profile and evaluated the inhibitory effects of extracts, alkaloid-enriched fractions and one of its major constituents on human neutrophil elastase (HNE). The monoterpene indole alkaloids (MIAs) strictosidine (1), (3α,5α)-5-carboxystrictosidine (2), strictosidine lactam (3), lyaloside (4), lyalosidic acid (5), 5-carboxystrictosamide (6), 3,4-dehydrostrictosidinic acid (7), and N-glucopyranosyl vincosamide (8) were characterized in mixture, in its leaves, and/or stems by using an integrated approach combining nuclear magnetic resonance (NMR) techniques, high performance liquid chromatography coupled to a tandem mass spectrometer with an electrospray ionization source (HPLC-ESI-MS/MS), and molecular networks. The crude leaf extract and an alkaloid-enriched fraction derived from it showed inhibitory activity against HNE. These results contribute to the chemical knowledge of the species and suggest its potential biological property.

Analytica doi: 10.3390/analytica7020030

Authors: Stela Jokić Ema Pavičić Valentina Masala Carlo Ignazio Giovanni Tuberoso Snježana Keleković Drago Šubarić Martin Lalić Krunoslav Aladić

The herbal tea industry has experienced substantial growth, particularly regarding green tea (Camellia sinensis). In the manufacturing of filter tea, fine herbal dust is generated as a residual by-product during grinding and sieving and is typically discarded as waste. This study aims to explore the application of ultrasound-assisted extraction (UAE) for secondary valorisation of green tea herbal dust by investigating the effects of various parameters on extraction efficiency. Antiradical activity of UAE extracts was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and the total phenolic content (TPC) was measured using Folin–Ciocalteu’s assay. Furthermore, selected phenolics were quantified by HPLC and qualitatively characterised by liquid chromatography coupled with electrospray ionisation and quadrupole time-of-flight tandem mass spectrometry (LC-ESI-QToF-MS/MS). The results demonstrate that UAE parameters have a pronounced influence on the antioxidant activity, TPC, and individual polyphenolic profile of green tea herbal dust extracts. Ethanol–water mixtures at a ratio of around 40–60%, as well as moderate impulse regimes (around 60%) and extraction times (around 10 min), were the most suitable for extracting green tea polyphenols. Epigallocatechin gallate was the predominant phenolic component in most extracts, alongside epicatechin, epigallocatechin, catechin, and gallic acid. The findings highlight the UAE technique as a robust, green, and scalable method for valorising green tea by-products, thereby facilitating the development of high-value natural extracts for applications in the food, pharmaceutical, and cosmetic industries.

Analytica doi: 10.3390/analytica7020029

Authors: Sebastian Scharf Lara Preuß Peter Winterhalter Recep Gök

C13-Norisoprenoids are important contributors to the aroma of Riesling wine. Their quantification is analytically challenging due to their low concentrations, the lack of commercial standards and their pronounced sensitivity to analytical conditions, reflecting their chemical lability, as well as the dynamic nature of the wine matrix, leading to high reactivity and, consequently, remarkable structural diversity. Here, we developed an assay for the analysis of C13-norisoprenoids in wine using headspace solid-phase microextraction coupled to gas chromatography–mass spectrometry (HS-SPME–GC-MS/MS). After evaluating different fiber materials, a statistical design of experiments (DoE) approach was employed to systematically optimize key HS-SPME parameters, including incubation, extraction and desorption conditions. Selected reaction monitoring (SRM) transitions were established for all targeted C13-norisoprenoids, allowing the assay to provide relative quantification of more than 40 compounds using representative labeled and unlabeled standards to generate linear calibration curves. Following method validation, this approach was applied to a young German Riesling wine to investigate the effect of various acidic hydrolysis conditions on the norisoprenoid profile as well as on specific compounds. A central composite design (CCD) was used to systematically study the impact of pH, temperature, and hydrolysis time. Quantitative data were obtained for 22 C13-norisoprenoids demonstrating that hydrolysis conditions strongly affected the norisoprenoid composition. pH and temperature showed a greater influence than reaction time. Response surface models (RSM) indicated that TDN, Vitispirane and TPB in particular are predominantly formed under strongly acidic and high-temperature conditions, whereas others such as Riesling acetal and actinidols are formed under milder conditions. The results indicate that hydrolysis conditions should be tailored to the specific norisoprenoid under investigation and the research question, particularly when simulating conditions of accelerated wine ageing for analytical purposes.

Analytica doi: 10.3390/analytica7020028

Authors: Isabella C. S. Nascimento Andressa M. Souza Andrea P. Parente Edna M. M. Oliveira Andrea Valdman Rossana O. M. Folly Andrea M. Salgado

A quartz crystal microbalance-based biosensor for the specific detection of the first transgenic common bean (L.) cultivar (BRS FC401 RMD) with resistance to Bean golden mosaic virus (BGMV) was developed. The immobilization chemistry relies on the strong bond between the thiolated probe and the gold electrode surface. The probe sequence is internal to a region of the BGMV rep gene that was introduced into the common bean genome. The sensor’s analytical performance was determined using synthetic oligonucleotides. Real samples of transgenic and wild-type bean seeds were also tested. Sample pretreatment consisted only of enzymatic fragmentation, followed by a thermal denaturation step combined with blocking oligonucleotides. Different biosensor regeneration approaches were studied. Immobilization showed good reproducibility (CV% of 5.8%). The biosensor proved specific for both synthetic oligonucleotides and non-amplified genomic DNA. A linear detection range of 0–1.4 ng/µL was observed, with a detection limit of 0.18 ng/µL. Three sequential detections were performed without loss of surface activity. The results demonstrate the biosensor’s potential for direct, real-time, label-free detection of DNA samples for field screening of transgenic common bean cultivars.

Analytica doi: 10.3390/analytica7020027

Authors: Diego García-Gómez Ana Ballester-Caudet María Esther Fernández Laespada

Secondary electrospray ionization mass spectrometry (SESI-MS) has emerged as a powerful technique for the real-time, non-invasive analysis of volatile organic compounds (VOCs) in complex matrices, such as exhaled breath and microbial volatilomes. However, its transition to routine application is hindered by significant challenges in absolute quantification, unambiguous identification, and standardization. This review provides a comprehensive overview of these limitations and the emerging solutions proposed to overcome them. Matrix effects, including gas-phase ion suppression and C-trap competition, are examined alongside mitigation strategies such as spectral stitching and standard addition. To enhance quantification stability, advanced standard delivery systems and dynamic quality control protocols are evaluated. The identification bottleneck—stemming from the absence of chromatographic separation—is addressed through the use of curated databases and advanced fragmentation techniques, such as incremental quadrupole acquisition to resolve overlapping spectra (IQAROS), to resolve isobaric interferences. Furthermore, the role of chemometrics in extracting biological fingerprints is discussed. Finally, the need for harmonized reporting standards and multicenter validation is emphasized to ensure cross-study reproducibility. Resolving these methodological gaps is essential for the clinical and industrial translation of SESI-MS.

Analytica doi: 10.3390/analytica7020026

Authors: Andrey Shishov Ekaterina Davydova Yaroslava Chepasova Nikita Tsvetov Alexey Savko Ilya B. Zavodnik

Natural deep eutectic solvents (NADES) offer sustainable alternatives to conventional solvents for plant extraction, yet their influence on extract composition and bioactivity preservation requires further study. Here, choline chloride-based NADES with lactic acid or propylene glycol were evaluated for ultrasound-assisted extraction (60 °C, 30 min, 1:20 w/v) of polyphenol-rich fractions from Sanguisorba officinalis and Symphytum officinale. Spectrophotometric analysis yielded total phenolic contents of 6.49–9.67 mg GAE g−1 and total flavonoids of 0.08–0.52 mg g−1, with values dependent on the plant matrix and the NADES formulation. Targeted HPLC-MS/MS enabled identification of representative phenolic acids (chlorogenic, caffeic, ferulic, rosmarinic) and flavonoid markers (rutin, quercetin derivatives), showing qualitative differences in the detected marker profiles between solvents and matrices. Functional assays demonstrated pronounced antioxidant-related effects, including DPPH radical scavenging at 0.5–25 µg mL−1 (polyphenols), inhibition of lipid peroxidation in rat erythrocytes at 0.25–1.20 µg mL−1, and modulation of mitochondrial respiration and permeability transition in isolated rat liver mitochondria. Overall, the results indicate that choline chloride-based NADES can be used to obtain polyphenol-rich plant extracts compatible with the applied analytical workflow while preserving redox-active fractions, supporting their utility in green analytical sample preparation.

Analytica doi: 10.3390/analytica7010025

Authors: Yiling Liu Jinjuan Xue Fan Xia Jia Chen Jianfeng Wu Shuxuan Cao Wei You Jinqiao Jiang Xiaolei Zhang Jianwei Xie

Phosphonyl tyrosine is one of the main biomarkers to confirm exposure to highly lethal organophosphorus nerve agents (OPNAs) in vivo. However, a critical challenge remains unresolved: ionization suppression occurs during the analysis of phosphonyl tyrosine by high-resolution mass spectrometry (HRMS) or tandem mass spectrometry (MS/MS), which is induced by the high concentrations of free amino acids present in the digestion solution. In this study, based on the broad-spectrum immunomagnetic beads with high affinity antibodies, a non-targeted early warning and verification strategy was developed. Compared with the recommended operating procedures for analysis in the verification of chemical disarmament, the total analysis time was reduced from several hours to about 30 min. Moreover, the detection sensitivity was increased by nearly one order of magnitude, and the detection limit (LOD) was 0.01 ng/mL. Furthermore, the screening strategy can cover all OPNAs listed as 1A.01, 1A.02 and 1A.03 in Schedule 1 of the CWC. Therefore, we have developed a rapid, sensitive, and broad-spectrum approach to accurately screen for OPNAs exposure, while also offering a novel strategy and technical support for chemical defense and occupational health assessment.

Analytica doi: 10.3390/analytica7010024

Authors: Milena Rmandić Marija Rašević Kostas Gkountanas Ana Protić Anđelija Malenović Yannis Dotsikas

Impurity profiling is of significant analytical and regulatory importance, particularly in the context of lifecycle quality management. A robust chaotropic chromatography method was developed for the determination of olanzapine and its two oxidative degradation products in tablets, in accordance with the ICH Q14 guideline and the principles of Analytical Quality by Design (AQbD). Risk assessment was performed using a combination of the Ishikawa diagram, CNX (Control, Noise and eXperimental) classification, and Failure Mode and Effect Analysis (FMEA). This multistep evaluation identified the critical analytical procedure parameters (APPs) as the acetonitrile content in the mobile phase, the concentration of perchloric acid in the aqueous phase, and the pH of the aqueous phase. These APPs were studied using an experimental design approach to model their effects on key analytical procedure attributes and to compute a multidimensional design space. Robust optimization supported by Monte Carlo simulations ensured compliance with predefined acceptance criteria with a probability of at least 95%. Method validation demonstrated adequate selectivity, limits of quantification of 0.75 µg/mL and 0.5 µg/mL for impurities B and D, linearity with correlation coefficients ≥0.990, accuracy of 98–102% for olanzapine and 70–130% for impurities, and repeatability with RSD ≤2% for the assay and ≤10% for impurities. The method was successfully applied to commercial tablet analysis.

Analytica doi: 10.3390/analytica7010023

Authors: Renata Karpicz Viktorija Rapalyte Danielis Rutkauskas

Light-sensitive protecting chemical groups play an important role in the control of chemical reactions with high spatial and temporal resolution. Various forms of o-nitrobenzyl as a protecting compound are used for light-directed DNA synthesis. The suitability of a particular derivative for the application is defined by its photolytic efficiency, a characteristic, that is commonly extracted from a repetitive HPLC procedure. Here, using an example of a phosphoramidite compound with improved properties of deprotection, we delineate a simplified and economic approach based on a measurement of absorbance spectra to evaluate the photolytic efficiency. The obtained values are in close agreement with those determined previously.

Analytica doi: 10.3390/analytica7010022

Authors: Mina Kim Sang Yun Han

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a powerful technique for polymer identification because it can ionize intact macromolecules with large molecular weights (>100 kDa) and detect them over a theoretically unlimited mass range. However, limited mass resolution, accuracy, and sensitivity in the high-mass region restrict detailed structural characterization of polymers. Depolymerization into smaller fragments using established chemistry, such as transesterification, provides a versatile alternative approach. The resulting characteristic fragments (<3 kDa) are polymer-specific and enable both polymer identification and detailed structural analysis, benefiting from the higher mass accuracy and sensitivity in the low-mass range and allowing MS/MS-based identification. To establish general sample-preparation conditions, this study systematically investigated the effects of transesterification of biodegradable polyesters using MeO−/MeOH, EtO−/EtOH, and t-BuO−/t-BuOH on subsequent MALDI-TOF MS analysis. Among the reagents examined, EtO−/EtOH combined with THAP/THF matrix treatment was found to be the most efficient, enabling rapid polyester analysis by MALDI-TOF MS within 10 min when the reaction time and reagent concentration were carefully controlled within an optimal window.

Analytica doi: 10.3390/analytica7010021

Authors: Atikah Mohd Nasir Nur Hanis Najihah Mohd Kamal Noor Hazfalinda Hamzah

The forensic reliability of biological fluids in sexual assault investigations depends on substrate type, environmental exposure, time since deposition, and analytical methodology. This systematic review evaluates the forensic reliability of major biological fluids, semen, blood, saliva, and vaginal secretions by comparing detectability and persistence on porous and non-porous substrates, assessing environmental and temporal effects on DNA integrity, and examining the performance of identification methods. A systematic search of PubMed, Scopus, and Web of Science (2001–2025) was conducted following PRISMA 2020 guidelines. Eligible studies investigated fluid persistence, degradation, or identification reliability under controlled or casework-relevant conditions. A weighted scoring framework categorised relative reliability. Twenty-seven studies met inclusion criteria. Semen and blood demonstrated higher reliability across substrates, particularly when collected within recommended timeframes. Porous substrates reduced surface detectability but occasionally preserved DNA from rapid degradation. Elevated temperature, humidity, and prolonged intervals consistently reduced DNA quality and detection success. Molecular approaches, including mRNA profiling, showed enhanced specificity in degraded or mixed samples, though methodological variability limited direct comparability across studies. The forensic reliability of biological fluids is context-dependent, shaped by complex interactions between substrate characteristics, environmental exposure, and analytical technique. Semen and blood remain robust DNA sources, while emerging technologies offer improved specificity in challenging scenarios. Standardised evaluation frameworks and timely evidence collection remain essential to enhance evidential value and minimise misinterpretation in sexual assault investigations.

Analytica doi: 10.3390/analytica7010020

Authors: Samuel King Brock Wright Cenk Suphioglu

Objectives: Using high-performance liquid chromatography (HPLC), we developed and validated an in vitro assay for the quantitative determination of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) activity, supplementing limited current methodologies to assess the efficacy of BACE1 inhibitor compounds. A hexa-histidine tagged peptide substrate of BACE1 was used as the analyte for the determination of in vitro BACE1 activity; it was validated according to ICH guidelines. Methods: The HPLC analysis was performed on the Agilent 1290 Series Infinity II UHPLC System equipped with a Phenomenex Kinetex EVO C18 (100 × 3 mm) 5 µm column. The method was developed using a gradient programme comprising 10% aqueous acetonitrile (0.02 M TFA) to 30% aqueous acetonitrile (0.02 M TFA) for 5 min at a flow rate of 0.6 mL/min. Results: The method showed linearity over the range of 14.92 to 72 µM with r2=0.9997. The accuracy of the method in terms of mean recovery ranged between 96.62 and 98.38%. The %RSD for intra- and inter-day precision was less than 5%. Two commercial inhibitors, AZD3839 and OM99-2, were used to evaluate the performance of the method at their respective IC50, resulting in inhibition of 53.46 and 50.74%, respectively. The described method addresses the void for a practical and cheap alternative to quantitatively determine the activity of BACE1 compared to current commercially available detection assays. Conclusions: We have successfully developed an HPLC method to measure the inhibitory function of two commercial inhibitors of BACE1, indicating the suitability of the method for the identification and characterisation of novel BACE1 inhibitors.

Analytica doi: 10.3390/analytica7010019

Authors: Fotouh R. Mansour Marcello Locatelli Reem H. Obaydo Amir Shaaban Farag Alaa Bedair

White Analytical Chemistry (WAC) provides a holistic framework for evaluating analytical methods by balancing analytical performance, environmental sustainability, and practical efficiency. Existing WAC assessment tools offer structured evaluation but often lack flexibility or comprehensiveness. To bridge this gap, we introduce the Whiteness Evaluation for Chemical Analysis (WECA) tool as a dynamic, web-based application that enables customizable, context-aware assessment of analytical methods. WECA allows users to select 2–4 criteria per RGB domain (Red: analytical performance; Green: environmental impact; Blue: practical efficiency), assign user-defined weights, and visualize results through an intuitive color-coded interface. The tool calculates a composite WECA score (%) that reflects overall method “whiteness”. Three case studies, covering HPLC-DAD, micellar electrokinetic chromatography, and electrochemical sensing, demonstrate WECA’s applicability and its ability to highlight method strengths and weaknesses across diverse analytical scenarios. WECA represents a step toward more adaptable, transparent, and visually intuitive method evaluation in alignment with the evolving principles of WAC.

Analytica doi: 10.3390/analytica7010018

Authors: Camila Bardy Luis Manuel Menéndez-Quintanal Gemma Montalvo Carmen García-Ruiz Begoña Bravo Serrano Jose Manuel Matey

High-resolution mass spectrometry (HRMS) enables non-targeted detection of drugs and metabolites in complex matrices. Phase II metabolites—especially glucuronides—are often the only detectable biomarkers in late or postmortem samples but are underrepresented in commercial libraries. This work pursued the prediction of phase II-glucuronide conjugates in diluted urine samples by non-targeted/targeted LC-HRMS workflows. A simply “dilute-and-shoot” qualitative UHPLC-HRMS/MS method (Q Exactive HF, ddMS2) was integrated with Compound Discoverer® software for data processing. The workflow incorporated predictive strategies such as exact mass suspect lists, Structured Query Language (SQL)-based filters, compound-class and diagnostic neutral-loss rules (including the characteristic loss of 176.0321 Da for glucuronides) and MS/MS confirmation using both in-house and public spectral libraries. An additional part of the application’s performance assessment involved its validation for diluted urine sample. A qualitative validated method for more than two hundred drugs in urine samples was performed, including the method’s selectivity/specificity, limit of identification, matrix effects, and potential carryover. Most analytes fulfilled the qualitative acceptance criteria, with more than 60% successfully identified at a concentration of at least 2.5 ng/mL. Matrix effects were within acceptable limits for most compounds, and no severe ion suppression was observed. A non-targeted workflow was applied to real forensic samples (n = 16), allowing a reduction of approximately 66,800 detected features to 225 glucuronide candidates, while a targeted workflow based on exact mass lists yielded 31 high-confidence identifications. Characteristic neutral losses and diagnostic fragment ions led to the tentative identification of some glucuronide phase II metabolites such as mirtazapine–glucuronide, morphine-6–glucuronide, and glucuronide conjugates of benzodiazepines and synthetic opioids. In conclusion, the integration of biotransformation knowledge with HRMS-based predictive filtering allows for the efficient and hydrolysis-free detection of glucuronide metabolites, thereby extending detection windows and enhancing toxicological interpretation in complex forensic scenarios. This adaptable and library-independent workflow also facilitates retrospective data mining, making it suitable for the identification of emerging substances and newly characterized metabolites.

Analytica doi: 10.3390/analytica7010017

Authors: Nurcan Dedeoğlu Seçil Karahüseyin

Taraxacum mirabile Wagenitz, one of the endemic riches of Anatolia, is a species that has remained largely unexplored regarding its enzyme inhibition profile despite its pharmacological potential. The effects of T. mirabile aerial and root extracts, obtained at different polarities, were scrutinized in this study against two important enzymes: lactoperoxidase (LPO), which plays a vital role in the innate immune system, and xanthine oxidase (XO), which is prominently associated with hyperuricemia and oxidative stress. The aerial and root portions of the plant were extracted into fractions of varying polarities using petroleum ether, dichloromethane, ethyl acetate, and butanol. LPO was isolated from buffalo milk (881.6-fold purification, 22.5% yield, and 1249.9 EU/mg specific activity) via affinity chromatography and used in in vitro inhibition assays alongside commercial bovine XO enzyme. The results showed that the ethyl acetate fraction of the aerial part of the plant exhibited the strongest LPO inhibition (IC50: 15.60 ± 0.77 µg/mL) among the fractions. The petroleum ether fraction of both the aerial part (IC50: 11.17 ± 0.94 µg/mL) and the root part (IC50: 11.61 ± 0.59 µg/mL) had the highest inhibitory effect for the XO enzyme. These distinct inhibition profiles allow for significant insights into how plant extracts with varying polarities modulate XO and LPO enzymes. In conclusion, the significant inhibitory activity of T. mirabile extracts toward LPO and XO enzymes highlights their potential as a natural source for developing effective enzyme inhibitors, which could be useful for therapeutic applications.

Analytica doi: 10.3390/analytica7010016

Authors: Paolo Inaudi Gabriele Ruggieri Elena Orrù Ornella Abollino Agnese Giacomino Letizia Mazzoni Mery Malandrino Francesca Durbiano

A simple mechanical polishing treatment of commercial solid-gold electrodes (SGEs) can renew the active gold surface, reduce manufacturing-related grooves, and markedly improve the repeatability of geometric-area estimation and the analytical performance in stripping voltammetry. The work focuses on the accurate determination of the geometric area of a SGE by two voltammetric techniques. Cyclic voltammetry (CV) at different scan rates, referred to as the Randles–Ševčik equation, and voltage scans at different electrode rotation rates, based on the Levich equation, were performed. The geometric area of the SGE was also evaluated by scanning electron microscopy (SEM). Commercial SGEs show grooves on their surface, derived from the fabrication processes. The effects of these grooves on the voltammetric response were investigated. The measurements were carried out on the SGE both as received from the manufacturer and after a reduction in the grooves height by a drastic mechanical treatment. After the treatment, the estimated area values were lower and more precise (3.05 ± 0.02 mm2). Moreover, the reduction in the grooves’ height affected the area estimations in contrast with the meaning of the geometric area, as intended by the Randles–Ševčik and Levich equations. Furthermore, the gold exposed surface was measured by CV in sulphuric acid. Finally, the SGE was tested for the detection of Hg in a NaCl solution by anodic stripping voltammetry: the repeatability of the response improved after the mechanical treatment, confirming the usefulness of this step before electrode usage.

Analytica doi: 10.3390/analytica7010015

Authors: Alissa Jonas Ian Gering Elena Schartmann Sarah Schemmert Dieter Willbold Beatrix Santiago-Schübel Janine Kutzsche

The all-d-enantiomeric-peptide RD2 was developed for the treatment of Alzheimer’s disease. This study aimed to develop a specific and highly sensitive liquid chromatography-mass-spectrometric (UHPLC-ESI-QTOF) method for quantifying RD2 in the mouse brain and to validate it according to the ICH M10 guideline to investigate the pharmacokinetic profile of RD2 in its target organ. Sample preparation, chromatographic separation and quantification were very challenging due to RD2’s highly hydrophilic properties, the complex matrix and the required lower limit of quantification (LLOQ). Chromatographic separation was performed on an Acquity UPLC BEH C18 column (2.1 × 100 mm, 1.7 μm particle size) within 5 min at 50 °C with a flow rate of 0.5 mL·min−1. Mobile phases consisted of water and acetonitrile with 0.2% formic acid and 0.015% heptafluorobutyric acid. Ions were generated by electrospray ionization in the positive mode, and RD2 was quantified by QTOF-MS. The developed extraction method revealed complete recovery. The linearity of the calibration curve was in the range of 2 ng·mL−1 to 500 ng·mL−1 (R2 > 0.99) with a LLOQ of 5 ng·mL−1. The intraday and interday accuracy and precision ranged from 0.4% to 12.2% and from 1.0% to 12.0%. RD2 remained stable in the freshly homogenized brain even after several freeze–thaw cycles, but stability decreased over time during long-term storage at −80 °C. Using this validated method, RD2-spiked brain homogenate samples and samples of a pharmacokinetic study with RD2 in mice were analyzed.

Analytica doi: 10.3390/analytica7010014

Authors: Zine Eddine Hamoum Hervé Carrier Brice Bouyssiere Marie Larregieu Pierre Chiquet Isabelle Le Hécho

In the context of the energy transition and the increasing deployment of low-carbon gases (hydrogen, biomethane), reliable analytical monitoring is required to support integrity assessment and traceability of gas infrastructures under diverse on-site conditions while limiting analytical costs through standardized sampling and a single analytical system. We developed and validated integrated workflows combining sampling and laboratory analysis for chemical and compound-specific isotope analysis (CSIA) of natural gas and associated gaseous effluents in underground storage. An original quantification approach was implemented, linking sampling pressure to the amount of each compound collected in vials, and coupled with δ13C and δ2H measurements of alkanes (C1–C3), CO2 and H2. Two complementary sampling modes were optimized and compared: conventional high-pressure cylinders and direct collection into vacuum-sealed vials suitable for a broad range of pressures and field conditions. Using reference gas mixtures and operational samples, both approaches showed good reproducibility and isotopic accuracy during laboratory validation and over two years of monitoring. In particular, δ2H determinations for alkanes and H2 remained robust under low-pressure sampling typical of annular spaces (~1–2 bar), despite gas-composition fluctuations. These validated methodologies provide a flexible basis for routine, standardized monitoring of stored and circulating gases, including emerging low-carbon components.

Analytica doi: 10.3390/analytica7010013

Authors: Emiliane Daher José Emeri Helvecio Vinicius Antunes Rocha Livia Deris Prado José Carlos Pinto

The primary objective of the current study is to establish and validate for the first time a method to determine and quantify praziquantel (PZQ) and its main degradation products loaded in poly(methyl methacrylate–co-2-(diethylamino)ethyl methacrylate) P(MMA-co-DEAEMA) microparticles. A high-performance liquid chromatography (HPLC) approach was developed and validated in accordance with the United States Pharmacopeia (USP) guidelines, addressing parameters such as accuracy, linearity, solution stability, precision, specificity, robustness, sensitivity, and system suitability. The method employed a gradient mobile phase consisting of ultrapure water and acetonitrile, flowing at a rate of 1 mL/minute over a Phenomenex Kinetex® C18 column (5 µm, 100 Å, 250 × 4.6 mm) maintained at 35 °C. Detection was performed at the wavelength of 210 nm using a DAD/UV detector. Samples of the active pharmaceutical ingredient (API) praziquantel, microencapsulated praziquantel, placebo, and a mixture of related substances (A, B, and C) were prepared with 0.5% formic acid in water/ethanol, 45:55 v/v as the diluent, and injected at 20 °C. The method demonstrated a limit of quantification (LOQ) of 0.20 µg/mL for praziquantel and related substances. The method exhibited an excellent linear response, with all correlation coefficients (R2) values exceeding 0.998, which is well above the recommended specified limit of R2 > 0.995. Percent recoveries fell within the acceptable range of (95.0–105.0%), and all results indicated a percentage of relative standard deviation (%RSD) ≤ 2.0, indicating a robust methodology. Thus, the proposed HPLC technique proved to be selective, accurate, sensitive, and consistent in analyzing both the material content and its main degradation products.

Analytica doi: 10.3390/analytica7010012

Authors: Marianna Ntorkou Christina Patakidou Styliani Nisyriou Constantinos K. Zacharis

The rapid growth and diversification of the cosmetic industry have led to increasingly complex formulations containing numerous bioactive ingredients, excipients, and synthetic additives, often delivered through advanced nanostructured systems. Ensuring product safety, efficacy, and regulatory compliance requires analytical approaches capable of accurately detecting both declared components and hazardous contaminants such as heavy metals, phthalates, nitrosamines, and banned preservatives or dyes. Traditional sample preparation methods are often solvent-intensive, time-consuming, and environmentally burdensome, prompting a shift toward green microextraction strategies aligned with the principles of green analytical chemistry. Techniques including solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE), and dispersive liquid–liquid microextraction (DLLME) offer miniaturized, solvent-efficient workflows with improved selectivity and sensitivity for complex cosmetic matrices. This review summarizes advances from the past five years in green microextraction methods for the determination of organic and inorganic species in cosmetic products. Emphasis is placed on their integration with separation techniques and applicability across product categories. Emerging trends, analytical challenges, and future directions toward more sustainable cosmetic safety assessment are also highlighted.

Analytica doi: 10.3390/analytica7010011

Authors: Laura Favilli Valentina Isaja Paolo Inaudi Agnese Giacomino Mery Malandrino Stefano Bertinetti Egle Trincas Hatice Cansu Sezer Ornella Abollino

Molting is an important biological and physiological stage in penguins, influenced by environmental and nutritional factors. Feather composition analysis before and after molting can consequently place boundaries on element bioaccumulation and excretion. We quantified and compared elemental concentrations in African penguin (Spheniscus demersus) feathers collected pre- and post-molt across three zoos to evaluate how molt stage and zoo-specific conditions influence feather elemental composition. Feathers were retrieved from individual penguins at Zoom Torino (Italy), Overloon ZooParc (Netherlands), and Zoo Magdeburg (Germany). Quantification of elemental concentrations were performed by analytical methods, with both ICP-OES and HR-ICP-MS techniques. A statistical approach involving MANOVA and factorial analysis helped identify important trends. Pre-molt features had more variability than post-molt, with both showing significant differences in elemental concentrations. Factorial analysis showed geogenic trends in Mg, Sr, and Ni trends as well as anthropogenic trends in Pb. While Na and K differed among all treatment groups, this likely points to physiological adaptations in response to increased demand during feather regrowth. Additionally, inter-zoo comparisons highlighted distinct elemental profiles linked to local environmental and dietary conditions, particularly in Zoo Magdeburg, where Na levels were markedly elevated. This study highlights the influence of environmental and dietary conditions on feather composition during molt, offering insights for improving captive penguin welfare and broader ecological implications related to climate change and pollution.

Analytica doi: 10.3390/analytica7010010

Authors: Lucie Jurkaninová Ivan Švec Soňa Gavurníková Marcela Sluková Peter Hozlár Michaela Havrlentová

Oats (Avena sativa L.) are a rich source of β-d-glucans, dietary fibre, proteins, and lipids. However, the behaviour of these components in wheat–oat composite systems during baking, particularly with regard to matrix-dependent analytical responses, remains unclear. This study evaluated the compositional changes, technological performance, and sensory quality of wheat bread enriched with various forms of oat. Composite flours containing 5–15% wholegrain oat flour, commercial oat bran, milled commercial oat flakes, or milled sprouted oat grain (sprouted under laboratory conditions for three days at 25 °C) were prepared using the Slovakian oat cultivar ‘Peter’. The raw materials, flour blends, and baked breads were analysed for β-d-glucans (BG), total dietary fibre (TDF), starch, proteins, and lipids using standardised enzymatic, gravimetric, and polarimetric methods. Bread quality was assessed through loaf volume measurements and a sensory evaluation using a 5-point hedonic scale by seven trained panellists. Multivariate statistical analysis was applied to integrate compositional, technological, and sensory data. Compared to wheat flour (0.24% BG and 3.45% TDF), the incorporation of oats significantly increased the contents of BG, TDF, proteins, and lipids, with oat bran showing the strongest enrichment effect (owing to 15.69% TDF in the raw material). Baking induced oat-form-dependent changes in the measured BG and TDF content. The level of BG diminished in wholegrain oat blends but increased or remained stable in bran-rich systems. This reflects differences in matrix structure and analytical extractability, rather than true compositional gains. Meanwhile, starch content consistently declined across all composite breads. Fibre-rich formulations exhibited reduced loaf volume and altered both bread geometry and morphology, particularly at 15% substitution. Breads containing 5% oat flour or moderate levels of oat bran (5 or 10%) were considered the most acceptable in terms of nutritional enhancement and quality attributes. Germinated oat breads showed the greatest technological impairment and the lowest sensory scores. Overall, moderate oat enrichment strikes a balance between nutritional improvement and technological performance without significantly compromising sensory quality. These findings emphasise the significance of matrix effects when interpreting standard total dietary fibre and β-d-glucans analyses and offer an integrated analytical and technological framework for the rational design of fibre-enriched cereal products.

Analytica doi: 10.3390/analytica7010009

Authors: Francesca Sebastiani Francesca Tombolini Fabio Boccuni Claudio Natale Silvia Canepari Riccardo Ferrante

Titanium dioxide (TiO2) nano- and submicrometric particles’ widespread use in different sectors raised concerns about human and environmental exposure. The validation of analytical methods is essential to ensure reliability in risk assessment studies. In this study, a single-particle inductively coupled plasma mass spectrometry (spICP-MS) method was validated for the detection, quantification, and dimensional characterization of TiO2 particles in biological tissues. Tissue samples collected after exposure to TiO2 particles underwent mild acidic digestion using a HNO3/H2O2 mixture to achieve complete matrix decomposition while preserving particle integrity. The resulting digests were analyzed by ICP-MS operated in single-particle mode to quantify and size TiO2 particles. Method validation was conducted according to ISO/IEC 17025:2017 and included linearity, repeatability, recovery, and detection limit assessments. The limit of detection for TiO2 particles was 0.04 µg/g, and 55.7 nm was the size the detection limit. Repeatability was within 0.5–11.5% for both TiO2 mass concentrations and particle size determination. The validated method was applied to tissues from inhalation-exposed subjects, showing TiO2 levels of 80 ± 20 µg TiO2/g and particle number concentrations of 5.0 × 105 ± 1.2 × 105 part. TiO2/mg. Detected TiO2 particles’ mean diameter ranged from 230 to 330 nm. The developed and validated spICP-MS method provides robust and sensitive quantification of TiO2 particles in biological matrices, supporting its use in human biomonitoring and exposure assessment studies.

Analytica doi: 10.3390/analytica7010008

Authors: Igor E. Uflyand Anastasiya O. Zarubina Aleksandr A. Shcherbatykh Vladimir A. Zhinzhilo

The present paper reports the preparation of a nanocomposite thin film consisting of calcium itaconate and graphene oxide (GO). The composite is a black powder consisting of individual shiny prismatic crystals at varying degrees of maturity. The crystal size distribution is quite narrow: from 3.6 to 6.2 μm in length and from 0.7 to 1.1 μm in width. Thin-film-based acetone sensor made of a nanocomposite was fabricated by spin coating of calcium itaconate–GO nanoparticles on glass plates. The thin-film acetone sensor was characterized using FTIR, XRD, SEM, TEM, and the low-temperature nitrogen sorption–desorption method. The sensor response time is 7.66 ± 0.07 s (sr = 0.92%), and the relaxation time when blowing the surface with clean air or inert gas (nitrogen, argon) is 9.26 ± 0.12 s (sr = 1.28%). The sensing mechanism of the sensor for detecting acetone at room temperature was also is proposed based on phenomenological understanding due to the absence of direct electronic/charge-transport evidence.

Analytica doi: 10.3390/analytica7010007

Authors: Dagmar Remeteiová Silvia Ružičková Ľubomír Pikna Mária Heželová

Interactions between alkaline solutions and the surface of pyrolytically coated graphite tubes (PCGTs) with/without a platform for determination of vanadium using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS) are discussed. Changes on the surface of tubes, lifetime of tubes, and formation of memory effect in the determination of vanadium in alkaline solutions (NaOH, Na2CO3, and real alkaline slag leachates) were investigated. Based on the results obtained, it is possible to state that HR CS GFAAS determination of vanadium content in alkaline solutions reveals that PCGTs with a platform are more susceptible than those without a platform to the formation of deposits and degradation of the platform surface, especially after the application of hydroxide environments. More marked and faster formation of deposits leads to shortening of the analytical lifetime of PCGTs with a platform (approx. 70 atomization/analytical cycles (ACs)) compared to PCGTs without a platform (approx. 290 ACs). The mechanical life of both types of tubes is comparable (approx. 500 ACs). Deposits formed on the internal surface of PCGTs can be removed in the presence of a carbonate environment and higher temperatures. Damage to the PCGT surface leads to the formation of scaled shapes and cavities, which can result in decreased absorbance due to losses of vanadium in the cavities (negative measurement error), or in increased absorbance by washing out of vanadium from the cavities (positive measurement error, and formation of memory effect). It was found that more frequent cleaning of PCGTs by performing ACs in an environment of 4 mol L−1 HNO3 can eliminate these unfavourable phenomena. Our results have shown that in the case of samples analysed with different sample environments (acidic vs. alkaline), the surface material of the tube/platform wears out more quickly, and therefore it is necessary to include a cleaning stage after changing the nature of the environment.

Analytica doi: 10.3390/analytica7010006

Authors: Thieli Schaefer Nunes Lucas Schmidt Kayla Peterson Rosalind Wright Julio Alberto Landero-Figueroa

Iodine is essential for thyroid hormone synthesis and is particularly critical during pregnancy, where excess and mainly its deficiencies can impair fetal neurodevelopment and increase maternal complications. Bromine has also gained attention due to its potential to interfere with iodine metabolism and contribute to adverse health effects when present in excess. Monitoring iodine and bromine in biological samples, especially urine and serum, is therefore important for assessing thyroid function and population health. This work presents a simple and robust ICP-MS method for simultaneous determination of bromine and iodine in urine and serum. The procedure uses a 20-fold dilution with 10 mmol L−1 ammonia containing 0.1% (w/w) EDTA-2Na, ensuring solution stability, minimizing sample-to-sample variability, and eliminating the need for matrix-matched calibration. EDTA-2Na effectively prevents precipitation of metal species at high pH, avoiding blockages in the sample introduction system. Method accuracy was confirmed through certified reference materials and spike-recovery experiments, both showing suitable agreement for the two analytes. Precision was consistently strong (RSD < 6%), and low detection limits were achieved (0.78 μg L−1 for Br and 0.24 μg L−1 for I). The use of a high-efficiency nebulizer enabled analysis with only 50 µL of sample, making the method suitable for limited-volume specimens. Overall, this approach provides a sensitive, accurate, and practical solution for large-scale population studies and clinical applications.

Analytica doi: 10.3390/analytica7010005

Authors: Ilias Barrak Ikrame Ayouch Zineb Kassab Youness Abdellaoui Jaber Raissouni Said Sair Mounir El Achaby Khalid Draoui

The objective of this research is to develop environmentally friendly, risk-free and effective adsorbent composite beads that remove Cu(II) ions from aqueous solutions using cost-effective biopolymers (Carboxymethylcellulose (CMC) and sodium alginate (AL)). The synthesized hydrogel beads (AL@CMC) were dried using two drying modes, namely air-drying and freeze-drying, and characterized using scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and Brunauer–Emmett–Teller (BET) analysis. The study investigated factors such as pH, adsorbent dosage, reaction time, Cu(II) ions concentration, and temperature to elucidate the adsorption mechanisms involved in removing copper ions. The results indicated that the hydrogel exhibited a maximum adsorption capacity of 99.05 mg·g−1, which is highly competitive compared to previous studies; the AL@CMC beads prepared in this work show a significantly higher adsorption capacity, improved stability due to the interpenetrated biopolymer network, and a clear enhancement from freeze-drying, which greatly increases porosity and active surface area. In addition, the pseudo-second-order nonlinear kinetic model best described the experimental data, implying the chemical nature of the adsorption process. Furthermore, the thermodynamic studies revealed that the adsorption process was endothermic, spontaneous, and homogenous. A Monte Carlo simulation model was utilized to ensure compatibility with the adsorption mechanism, in order to delve deeper into the intricacies of the adsorption process and gain a more comprehensive understanding of its underlying mechanisms and behavior. In conclusion, the prepared hydrogel beads proved to be an effective adsorbent for efficiently removing copper ions, making them a promising solution for addressing Cu(II) ion pollution.

Analytica doi: 10.3390/analytica7010004

Authors: Scarlat Ohanna Dávila da Trindade Thaís Cristina de Oliveira Cândido Matheus Martins Guedes Arnaldo César Pereira

Additive manufacturing, particularly fused deposition modeling (FDM), has emerged as a promising approach for producing electrochemical sensors based on conductive thermoplastic composites. In this study, the effects of various printing parameters (extrusion temperature, layer height and width, printing speed, and the number of conductive layers) on the electrochemical performance of PLA/CB electrodes fabricated via FDM were investigated. Electrochemical impedance spectroscopy analyses showed that properly adjusting these parameters promoted the formation of more efficient conductive pathways and reduced charge transfer resistance during monitoring of the redox behavior of the potassium ferrocyanide/ferricyanide probe. Furthermore, the electrochemical performance of the device was demonstrated through the detection of different model analytes, including dopamine, catechol, hydroquinone, paracetamol, and uric acid. The device was also applied to the determination of dopamine, achieving a detection limit of 0.16 µmol L−1. Overall, the results highlighted that optimizing printing conditions is essential for improving the electrochemical performance of 3D-printed devices, reinforcing the potential of 3D printing as a promising route for the fabrication of electrodes for electroanalytical applications.

Analytica doi: 10.3390/analytica7010003

Authors: Ignjat Filipović Snežana Stojanović Jelena Petronijević Milena Milutinović Danijela Nikodijević Nevena Petrović Marijana Kosanić Nenad Joksimović

The urgent need for effective therapies against cancer and antimicrobial-resistant pathogens motivates the development of novel metal-based complexes. Herein, we report the synthesis and characterization of four novel cobalt(II) complexes with biologically relevant β-diketo ester ligands. The complexes were characterized via UV-Vis, FTIR, mass spectrometry, and elemental analysis. Their biological activities were evaluated through antimicrobial and cytotoxic assays. Complex B1 exhibited the strongest antimicrobial activity, with minimum inhibitory concentrations (MICs) of 0.23 mg/mL against Staphylococcus aureus and Proteus mirabilis, and 0.01 mg/mL against Mucor mucedo, exceeding the performance of ketoconazole. Cytotoxicity studies on SW480 colorectal cancer cells and HaCaT normal keratinocytes identified B3 as the most potent anticancer agent (IC50 = 11.49 µM), selectively targeting tumor cells. Morphological analysis indicated apoptosis as the primary mode of cell death. Mechanistic studies were performed to elucidate interactions with biomolecules. UV-Vis and fluorescence spectroscopy, viscosity measurements, and molecular docking revealed that B3 binds strongly to calf thymus DNA via hydrophobic interactions and groove binding, and exhibits selective binding to bovine serum albumin (site II, subdomain IIIA). These results highlight the potential of cobalt(II) complexes as multifunctional agents with significant antimicrobial and antitumor activities and provide detailed insight into their molecular interactions with DNA and serum proteins.

Analytica doi: 10.3390/analytica7010002

Authors: Miriam Demtschuk Priska Heinz

In clinical medicine it is of interest to know vitamin C blood levels. There are numerous variations in published sample preparation methods for quantifying vitamin C using HPLC. For the determination of vitamin C in human probes, the method needs to be simple, fast, and accurate. A systematic search in Pubmed was carried out to identify the methods for the quantification of vitamin C with HPLC in combination with a UV detector in human plasma. A total of 83 reports were screened, from which seven methods were selected and examined in detail. Tabular overviews compare the different sample preparation options, HPLC parameters, and validation criteria. Different reagents for protein precipitation and extraction are discussed. By allowing the user to see the criteria of interest at a glance, it can be used as a tool for the rapid development and establishment of a vitamin C determination method using HPLC.

Analytica doi: 10.3390/analytica7010001

Authors: Pasant T. Elbanna Mohamed A. Hammad Inas A. Abdallah Marcello Locatelli Fotouh R. Mansour

Exploring green organic solvents is a global demand. Most of the currently used solvents pose some concerns regarding environmental sustainability and occupational health risks. In this work, propylene glycol was employed for the first time as a green solvent for mobile phase preparation in the reversed phase chromatographic separation of a mixture of two antioxidants, glutathione and ascorbic acid. The slight viscosity of propylene glycol was manipulated by using water as a co-fluidizing agent to facilitate pumping. Method optimization was performed using factorial design experimental Expert 13® Software (Minneapolis, MN, USA) to achieve the maximum resolution and the minimum run time. The reported method was properly validated according to the International Conference on Harmonization criteria at the linearity range of 1–500 µg/mL, with acceptable accuracy and precision for both drugs. The method was effectively applied for the quantification of both drugs in their commercial pharmaceutical formulation. The proposed method was assessed for environmental and operator safety by means of global tools like AGREE and MoGAPI and has proved high degrees of greenness. Propylene glycol has several benign properties, such as low volatility, less toxicity, compatibility with UV detectors and very low flammability, that will soon assemble it as a promising alternative for the conventionally used solvents.

Analytica doi: 10.3390/analytica6040059

Authors: Olga V. Levitskaya Tatiana V. Pleteneva Elena V. Uspenskaya Daria A. Galkina Daiaana D. Ogotoeva Nadezda A. Khodorovich Anton V. Syroeshkin

Quality control of herbal medicinal products (HMPs) is challenging due to their multicomponent composition. For most HMPs, chemical reference standards (CRSs) required for traditional chromatographic and spectral analyses are unavailable. According to USP and Ph. Eur., an exception is valerian tincture, for which highly specific CRSs have been developed. The aim of this study was to use principal component analysis (PCA) and the novel two-dimensional diffuse laser scattering (2D-DLS) method to identify HMPs and their aqueous-ethanolic extracts according to their botanical genera without relying on specific marker compounds. Spectral data were compiled into an extensive library covering a wide wavelength range—from 0.02 nm to 15,000 nm. PCA of the spectral data (UV spectrophotometry, fluorimetry, FTIR spectroscopy, and X-ray diffraction) enabled clustering of samples by individual botanical genera. The most significant information for sample differentiation was provided by wavenumbers of 1400, 1180, and 931 cm−1 in the IR spectra and wavelengths of 450 nm and 672 nm in the UV and fluorescence spectra, respectively. During model cross-validation, all “blind samples” were correctly classified by botanical genus, achieving a non-error rate (NER) of 100%. Furthermore, the unique 2D-DLS method was used to rapidly identify tinctures without opening the glass bottles.

Analytica doi: 10.3390/analytica6040058

Authors: Maksim N. Zavalishin Gleb A. Nikitin Vladimir S. Osokin George A. Gamov

This paper presents the design and evaluation of a fluorescent probe based on fluorescein hydrazide for the selective detection of hypochlorite (ClO−), bromide (Br−), and iodide (I−) ions in solution. The starting chemosensor, fluorescein hydrazide, is suitable for detecting hypochlorite anions in solution, as observed for the first time. The Br− and I− ions could be discovered after activating the probe with hypochlorite. Upon interaction with ClO− ions, the proposed probe exhibits a significant increase in fluorescence emission, a sharp rise in absorbance, and a distinct color change, which is attributed to the conversion from the spirolactam closed form to the open form of the fluorescein ring. ClO− and Br− ions added together were found to brominate the probe in an acetonitrile–water mixture, resulting in a pronounced bathochromic shift in both absorption and emission spectra. Notably, the combination of ClO− and I− was more effective in cleaving the spirolactam ring than hypochlorite alone. Quantum chemical calculations were used to understand the detection mechanism of Br and I ions in a probe–hypochlorite mixture. The probe demonstrated exceptional selectivity and rapid response towards the target analytes, with detection limits determined to be 2.61 μM for ClO−, 66 nM for Br−, and 13 nM for I−. Furthermore, it successfully monitored fluctuations in ClO−, Br−, and I− concentrations within complex systems, highlighting its potential application in environmental and biological monitoring.

Analytica doi: 10.3390/analytica6040057

Authors: Juan Pablo Hervás-Pérez Laura Martín-Carbajo Marta Sánchez-Paniagua

Alterations in the expression of the Klotho gene have been associated with chronic kidney disease (CKD), and its potential as an early diagnostic biomarker is currently under active investigation. In this work, we report the development of a highly sensitive, label-free electrochemical DNA-based biosensor for the detection of a 100 mer DNA fragment corresponding to a partial region of Klotho mRNA. The proposed bioplatform integrates mixed self-assembled monolayers (SAMs) and gold nanoparticles for efficient DNA immobilization within a sandwich-type configuration, coupled with impedimetric detection. Different SAM architectures were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy, with the binary monolayer composed of 1-hexadecanethiol (HDT) and the capture probe (CP) exhibiting the best analytical performance. The use of gold nanoparticle-modified screen-printed carbon electrodes (AuNPs–SPCEs) resulted in a 1.4-fold increase in the signal-to-noise ratio compared to screen-printed gold electrodes. Additionally, the incorporation of a blocking step using bovine serum albumin (BSA–HDT–CP–AuNPs–SPCE) enhanced the sensitivity by 1.6-fold compared to the unblocked system. The genosensor displayed a linear response in the concentration range of 3 × 10−10 to 7.5 × 10−8 M, achieving a detection limit of 0.09 nM. Relative standard deviations below 7.5% were obtained for different Klotho concentrations, confirming high intra-assay and intermediary precision. Selectivity assays demonstrated negligible signals for non-complementary sequences, while recovery experiments in spiked human serum samples yielded satisfactory values between 96.5% and 103.4%.

Analytica doi: 10.3390/analytica6040056

Authors: Hiba Agnaou Hela Refai Spyros Grigorakis Dimitris P. Makris

Waste orange peels (WOP) are a major orange processing residue, and they may be a rich source of precious bioactive polyphenols. Amongst the various WOP constituents, hesperidin holds a prominent position as the most abundant polyphenolic metabolite, with proven biological properties. The current work was performed to provide detailed information on the effect of various acid catalysts to assist hesperidin recovery, using an ethanol organosolv treatment. The treatment developed was first examined by comparing inorganic (HCl) and natural organic (oxalic, citric) acids for their influence on process performance, extraction kinetics, and severity. Following this, optimization was accomplished through response surface methodology, and the extracts produced were investigated with respect to their polyphenolic composition and antioxidant characteristics. The HCl-catalyzed treatment, carried out with 70% ethanol/2% HCl, was proven the most efficacious, giving a total polyphenol yield of 30.7 mg gallic acid equivalents per g of dry mass, and it was shown that the treatment yield was related to severity, obeying a power model. Liquid chromatography–tandem mass spectrometry analysis of the extract generated under optimized conditions (170 min, 80 °C) revealed that hesperidin was extensively hydrolyzed into hesperetin 7-O-glucoside and aglycone (hesperetin). Such an effect was very limited with the oxalic acid-catalyzed treatment, whereas citric acid did not affect the original polyphenolic composition. Overall, the HCl-catalyzed treatment was of significantly higher performance, providing a total flavanone yield of 21.22 mg per g dry mass. The results of this investigation may be of value in adjusting treatment settings for (i) increased flavonoid recovery from WOP and (ii) producing extracts enriched in hesperidin and/or its hydrolysis derivatives. Such practical recommendations may assist the establishment of WOP valorization processes in an integrated biorefinery prospect.

Analytica doi: 10.3390/analytica6040055

Authors: Vitaliy Fomin Milana Turovets Nabira Kelesbek Assanali Ainabayev Daniyar Sadyrbekov Dauletkhan Kaykenov Askhat Borsynbayev Nurbakyt Azhibay Saule Aldabergenova

A probabilistic–deterministic design of experiments (PDDoE) approach was employed to optimize laser-induced breakdown spectroscopy (LIBS) parameters for the quantitative determination of minor components in lead-based alloys. The PDDoE optimization identified 18 J laser pump lamp energy, 1 µs delay, and 1 µs exposure as optimal conditions, minimizing spectral dispersion (5–8%) and ensuring stable plasma formation. The acquired spectra were subsequently processed in an R-based automated workflow, where Linear, Lasso, and Ridge regression models were used to establish quantitative relationships between normalized line intensities and atomic absorption spectroscopy (AAS) reference data. The resulting models demonstrated high accuracy (R2 = 0.97 for Sn, 0.985 for Sb, 0.982 for Bi, 0.919 for As, and 0.905 for Ag), with prediction errors (RMSE) below 10% and limits of quantification (LOQ) under 0.05 wt.%. Principal component analysis (PCA) applied to 43 historical (19th–20th century) and technogenic samples (19th–20th century) allowed us to isolate clusters of Pb–Sb alloys corresponding to secondary accumulator materials, alongside a diffuse group of nearly pure Pb specimens containing variable minor impurities. The combined PDDoE–LIBS–R analytical framework provides a reproducible, non-destructive, and chemometrically validated methodology for the quantitative characterization and classification of archeological and industrial lead alloys.

Analytica doi: 10.3390/analytica6040054

Authors: Keita Saito Yuki Takeuchi Hiroyuki Kataoka

Volatile organic compounds (VOCs) emitted from human skin are promising biomarkers for non-invasive health assessment and disease diagnosis. However, efficient collection and sensitive analytical methods for skin VOCs remain challenging. We developed a method for measuring ethanol, acetaldehyde, and acetone from palmar skin using glass cup aqueous sampling followed by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Compounds were extracted using a carboxen/polydimethylsiloxane fiber by HS-SPME and separated using a DB-1 capillary column within 5 min. The HS-SPME/GC-MS method showed linearity (5–1000 ng/mL, r ≥ 0.990) with detection limits of 0.56, 1.01, and 0.15 ng/mL for ethanol, acetaldehyde, and acetone, respectively. Intra-day and inter-day precision were ≤9.3% and ≤9.7%, with accuracy ranged of 94–110%. Five-minute palm contact with water caused VOC release to increase linearly, and samples remained stable for 24 h at −20 °C. Following ingestion of a 500 mL alcoholic beverage (5% ethanol), ethanol and acetaldehyde emissions peaked at 95 and 24 ng/cm2/min after 1 h, while acetone gradually increased to 1.3 ng/cm2/min after 6 h. This simple, rapid method enables practical assessment of skin VOCs for health monitoring and environmental exposure evaluation.

Analytica doi: 10.3390/analytica6040053

Authors: Jiawei Xu Tatsuya Fujino

We have developed mold matrices that can be employed to distinguish between enantiomers (D- and L-glucose) and structural isomers (n- and iso-stearic acid) in matrix-assisted laser desorption/ionization mass spectrometry. Utilizing a temperature-responsive polymer, a molecular structure recognition film was created around metal or semiconductor particles, such as silver (Ag) or cadmium telluride (CdTe), forming the core. Molecules that fit the template structure were selectively ionized. To elucidate the properties of the mold matrix, the relationship between molecular recognition rate and peak intensity of analyte ion was investigated by varying polymer film thickness around the core. The relationship between molecular recognition rate and hydrophobicity of the template molecule was also examined. It was found that increasing the amount of polymer forming the molecular recognition film improved the molecular recognition rate. However, the peak intensity of the analyte ion decreased. It was also found that using highly hydrophobic molecules as template molecules resulted in high molecular recognition rates. In addition, a water-splitting photocatalyst was synthesized and utilized to fabricate the mold matrix. It was applicable to both positive and negative ion generation while recognizing the molecular structure of the analyte.

Analytica doi: 10.3390/analytica6040052

Authors: Amalia Ridichie Adriana Ledeţi Cosmina Bengescu Laura Sbârcea Răzvan Adrian Bertici Denisa Laura Ivan Gabriela Vlase Titus Vlase Francisc Peter Ionuţ Ledeţi

Estrogens are cholesterol-derived hormones, with four endogenous estrogens being presented in the scientific literature, namely, estradiol, estrone, estriol, and estetrol. In this study, we aim to obtain a complete thermoanalytical profile for the three most important endogenous estrogens: estradiol, estriol, and estrone. To achieve this, the TG/DTG were registered in non-isothermal conditions at five different heating rates (β = 2, 4, 6, 8, and 10 °C min−1). To describe the mechanisms of the degradation processes, a complex kinetic analysis was performed by applying a preliminary method (ASTM E698), two isoconversional methods (Flynn–Wall–Ozawa and Friedman), and the non-parametric kinetic method. The results indicate that estradiol undergoes a single-step degradation process, while estriol and estrone present a complex degradation process. The determination of the shelf life of pharmaceutical products represents a critical factor in ensuring their safety and efficacy. This parameter can be estimated from the activation energy derived from non-isothermal experiments through the application of the Arrhenius equation and appropriate kinetic models.

Analytica doi: 10.3390/analytica6040051

Authors: Ebenezer O. Olaniyi Christopher Kucha Fanbin Kong

Nuts such as pecans, almonds, peanuts, pistachios, and walnuts are nutrient-dense foods rich in unsaturated fatty acids and antioxidant compounds. Their regular consumption has been linked to significant health benefits, including reduced risks of cardiovascular disease, diabetes, and high cholesterol. With increasing global demand, ensuring the quality of nuts before they reach consumers is critical. Conventional quality assessment methods dominate the industry but are often subjective, destructive, time-intensive, environmentally burdensome, and laborious. Therefore, there is an urgent need for rapid, non-destructive, and objective alternatives capable of meeting modern quality standards. In this systematic review, we summarize traditional approaches for evaluating nut quality parameters and introduce hyperspectral imaging as a novel technique with promising applications. We examine its use in detecting nut adulteration, assessing chemical composition, identifying defects, and evaluating other quality traits. Limitations of hyperspectral imaging in industrial settings are also discussed, along with potential solutions and future directions. Given the relatively limited research area, approximately 44 relevant studies were critically reviewed. This work provides valuable insights for researchers and industry stakeholders developing innovative technologies for nut quality assessment.

Analytica doi: 10.3390/analytica6040050

Authors: Peera Tabboon Ekapol Limpongsa Rapee Jarungsirawat Supawan Wechprakhon Jidapa Niyommoh Amika Wantong Napaphak Jaipakdee

A high-performance liquid chromatography method coupled with diode array detection (HPLC-DAD) was developed for simultaneous quantification of andrographolide (AG) and 14-deoxy-11,12-didehydroandrographolide (DDAG) in rat plasma. A salt-assisted liquid–liquid extraction (SALLE) procedure was optimized, with MgSO4 yielding the highest extraction efficiency (>90% for both AG and DDAG), outperforming conventional solvent extraction, and being comparable to solid-phase extraction. The method exhibited acceptable linearity (125–2000 ng/mL, R2 > 0.99), with low limits of detection and quantification of 60 and 70 ng/mL for AG and 201 and 234 ng/mL for DDAG, respectively, while adhering to the ICH M10 criteria for accuracy, precision, and stability under various storage conditions. Stability testing of the prepared samples demonstrated that >99% AG and 95% DDAG were retained when stored at low temperatures, specifically below 4 °C. The developed method was successfully applied in a pharmacokinetic study following oral administration of Andrographis paniculata extract (containing AG 7.5 mg/kg) to healthy Wistar rats. The SALLE-HPLC-DAD method developed herein enables selective AG quantification without significant matrix interference. In conclusion, this study introduces an alternative sample preparation and analytical method that is fast, cost-effective, and reliable, making it suitable for pharmacokinetic studies of the principal biomarker of Andrographis paniculata.

Analytica doi: 10.3390/analytica6040049

Authors: Luoana Florentina Pascu Valentina Andreea Petre Vasile Ion Iancu Ioana Antonia Cimpean Florentina Laura Chiriac

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that tend to accumulate in solid matrices such as sewage sludge, raising concerns regarding their fate and potential ecological risks. This study aimed to develop and validate a robust analytical method for the accurate determination of PFAS in dehydrated sludge. A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was optimized for 28 PFAS, including perfluoroalkyl carboxylic acids (PFCAs) and sulfonic acids (PFSAs). Solid–liquid extraction with basic methanol was followed by cleanup using a cartridge packed with ferrite and sodium sulfate to remove moisture and particulate interferences. Chromatographic separation was performed with an Avantor® ACE® PFAS Delay column coupled to an Agilent triple quadrupole MS operating in negative electrospray ionization mode. The method achieved excellent sensitivity (MDL < 0.02 µg/g dry weight for most compounds), satisfactory precision (RSD < 15%), and recoveries between 80–118%. Optimization of mobile phase additives, gradient conditions, and MS parameters enhanced chromatographic resolution and signal-to-noise ratio. The validated method demonstrates high reliability for PFAS determination in complex solid matrices and can be applied as a valuable tool for environmental monitoring and risk assessment of sludge management practices.

Analytica doi: 10.3390/analytica6040048

Authors: Abraham Kabutey Su Su Soe Mahmud Musayev Sonia Habtamu Kibret

The study evaluated the effect of moderate heating temperatures on physical, mechanical, and spectral properties of bulk flaxseeds and pressed oils. The samples of bulk flaxseeds were measured at 60 mm pressing height and subjected to pretreatment temperatures between 40 °C and 60 °C at 5 °C intervals at a constant heating time of 30 min. The uniaxial compression process, comprising a pressing chamber of a diameter of 60 mm with a plunger, was used for extracting the oil under a load of 300 kN and a speed of 5 mm/min. Prior to the oil extraction, the moisture content of the flaxseeds samples was determined to be 8.15 ± 0.07% d.b., and that of oil content was 40.32 ± 0.02%. Based on the results obtained, porosity, density, oil yield, and oil expression efficiency significantly correlated positively (p-value < 0.05) with the increase in heating temperatures. However, kinematic and dynamic viscosities, compressive stress, deformation energy, and hardness did not significantly correlate (p-value > 0.05) with heating temperature. The study revealed that heating temperatures increased oil yield from 11.54% to 24.18% and oil expression efficiency from 28.62% to 59.96% with the corresponding deformation energy of 0.698 ± 0.011 kJ at 60 °C. The findings suggest that mild thermal pretreatment of flaxseeds improves oil recovery with minimal energy requirement under the linear compression process.

Analytica doi: 10.3390/analytica6040047

Authors: Julio C. Avalos Eugenia Aldeco-Pérez Julieta Torres-González Raul Garcia-Garcia German Orozco

Major vibrational spectroscopy studies have focused on the preparation of chromium coatings via chemical processes (conversion coatings), and few studies have focused on electrochemical processes (electrodeposition). Initially, the chemical precursors were hexavalent chromium salts, but these compounds are now replaced by less toxic trivalent ions. There is a profound understanding of the process when vibrational spectroscopy is used in combination with other techniques. This is the case for chromium(VI) conversion coatings, and the results of several techniques, such as synchrotron infrared microspectroscopy, have made it possible to understand the structure of the two-layer coating and the chemical composition of each layer. Vibrational spectroscopy confirmed the mechanism for coating formation, in which ferricyanide was a redox mediator. In addition, vibrational spectroscopy was effective in determining the mechanism of corrosion resistance of the coatings. Conversely, there are very few studies on the electrodeposition of trivalent chromium ions, and the mechanics of electrodeposition are unknown. To simplify the use of spectroscopy, spectra of potassium dichromate and chromium(III) sulfate are presented as references for coating studies, and a compilation of Cr(III)−O and Cr(VI)−O vibrational modes is provided to facilitate band assignment. Our review highlights that spectroscopic techniques have been insufficiently applied in this field; however, the results of vibrational spectroscopy accelerate the transition to safer Cr(III) technology.

Analytica doi: 10.3390/analytica6040046

Authors: Olivia-Stella Salm Jaan Kers Maria Kulp

In modern circular-economy value chains, wood is frequently processed into fines, chips, or powders—forms in which anatomical features are no longer visible, rendering traditional visual identification methods ineffective. This study introduces a rapid, non-destructive attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectroscopy approach, combined with chemometric modeling, to address this challenge by enabling both the classification and compositional profiling of processed wood fractions. Using full-spectrum ATR-FTIR data, partial least squares discriminant analysis (PLS-DA) models achieved high-accuracy classification of wood by type, species, and provenance, with sensitivity and specificity reaching up to 1.00. In addition, PLS and backward interval BiPLS models predicted total lignin, acid-soluble lignin, and extractives with strong performance (R2 > 0.90, RPD > 2). Interval selection further enhanced prediction accuracy by reducing RMSEP by up to 30%, improving model stability for real-world application. By replacing slow, reagent-intensive wet chemistry with a rapid, green, and scalable technique, the presented methodology provides a valuable tool for authentication, quality control, and resource optimization when dealing with mechanically processed or recycled wood.

Analytica doi: 10.3390/analytica6040045

Authors: Huijun Wang Yuangui Yang Yueyi He Hongbo Xu Shizhong Chen

In this study, an integrated analytical method coupling ultra-high-performance liquid chromatography–photodiode array detection–quadrupole time-of-flight mass spectrometry with total antioxidant capacity determination (UHPLC-PDA-Q-TOF/MS-TACD) was developed for the rapid screening and identification of antioxidants in complex natural extracts. The system enables simultaneous chromatographic separation, mass spectrometric characterization, and on-line activity assessment by combining 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and ferric ion reducing antioxidant power (FRAP) assays. When applied to Rosa rugosa samples from five different origins, the approach efficiently separated the extract and successfully localized antioxidants directly from the chromatographic profile. A total of 86 compounds were identified, including flavonoids, tannins, and phenolic acids. Among them, 60 exhibited free radical scavenging capacity and 59 showed reducing activity. Activity verification experiments showed that all seven compounds exhibited good antioxidant activity. The IC50 values of gallic acid, ellagic acid, quercetin 3-O-rhamnoside, and rutin were 0.019, 0.025, 0.043, and 0.046 mM, respectively, which were significantly better than the positive control (vitamin C). This method provides methodological and technical support for the rapid discovery of antioxidant components in complex natural products.

Analytica doi: 10.3390/analytica6040044

Authors: Sara Madji Julien Antih Malak Tabib Charlotte Silvestre Anissa Ghennai Audrey Warnery Fabrice Vaillant Florence Bichon Aude Echalier Patrick Poucheret

In recent years, research and development in the field of green extraction of bioactive compounds from plants has intensified. This increased focus is driven by market trends, environmental concerns, and consumers’ growing interest in natural and healthy ingredients, as well as bioactive compounds. This development aligns with a global trend toward more sustainable use of natural resources. In this context, macroalgae have been recognized as valuable sources of bioactive compounds with various health benefits. These molecules include proteins, fatty acids, vitamins, and pigments. Phycobiliproteins (PBPs) are pigments and metabolites of particular interest that can be extracted from microalgae. This group of colored proteins, mainly present in cyanobacteria and red algae, is known to have a wide range of potential applications. However, conventional methods for extracting PBPs, such as homogenization, maceration, and freezing, are time-consuming and energy-intensive, often producing unsatisfactory yields. As a result, new extraction technologies have been developed, including ultrasound-assisted extraction, ionic liquid extraction methods, and the use of natural deep eutectic solvents. This review summarizes existing green processes for extracting and purifying PBPs, with the aim of enabling feasible and sustainable valorization of algae. Specifically, it covers various extraction and purification techniques of PBPs, as well as the effects of environmental growth conditions on the production of these metabolites. It also highlights the biological and pharmacological activities of PBPs and explores their potential applications in the food, cosmetic, and biomedical sectors.

Analytica doi: 10.3390/analytica6040043

Authors: Ardiana Topi Agim Kasaj Daniel Hudhra Hasim Kelebek Gamze Guclu Serkan Selli Dritan Topi

Wine phenolics serve as robust chemical signatures correlated to grape variety, processing, and regional identity. This study explores the potential of machine learning algorithms, combined with the phenolic profiles of Albanian wines, to classify them according to grape variety. Geographic origin analysis was conducted as a preliminary exploration. The dataset of phenolic compounds included white and red wines, spanning the 2017 to 2021 vintages. Using five supervised algorithms—Support Vector Machine (SVM), Random Forest, XGBoost, Logistic Regression, and K-Nearest Neighbors—a high classification accuracy was achieved, with SVM reaching 100% under Leave-One-Out Cross-Validation (LOOCV). To address class imbalance, the Synthetic Minority Over-sampling Technique (SMOTE) and stratified cross-validation were applied. Random Forest feature importance consistently highlighted trans-Fertaric acid and Procyanidin B3 as dominant discriminants. Parallel coordinates plots demonstrated clear varietal patterns driven by phenolic differences, while PCA and hierarchical clustering confirmed unsupervised grouping consistent with wine type and maceration level. Permutation testing (1000 iterations) confirmed the non-randomness of model performance. These findings show that a small set of phenolic markers can offer high classification accuracy, supporting chemically based wine authentication. Although the dataset is relatively small, thorough cross-validation, non-redundant modeling, and chemical interpretability provide a solid foundation for scalable methods. Future work will expand the dataset and explore sensor-based phenolic measurement to enable rapid authentication in wine.

Analytica doi: 10.3390/analytica6040042

Authors: Ayşe Pınar Yağcılar Emre Şefik Çağlar Neslihan Üstündağ Okur

This study was designed for the analytical method development and validation for Calcium butyrate (CAB) using High-Performance Liquid Chromatography (HPLC). 1H and 13C Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FTIR) spectroscopy analysis were carried out to examine the molecular structure. For HPLC analysis, a blend of acetonitrile and phosphoric acid solution (0.1%) (20:80) (v/v) was used as a mobile phase. A C18 column (5 µm, 250 × 4.6 mm) was used as a stationary phase. The eluent of CAB was monitored with a UV detector at a wavelength of 206 nm and a flow rate of 1 mL/min. According to the results, FTIR and NMR spectra were consistent with the structural characteristics of CAB, and the expected proton and carbon signals were observed. During the HPLC analysis, due to the ionization of CAB, three distinct retention times were observed in the chromatograms at 3.4, 4.5, and 7.4 min. The validation was performed according to ICH guidelines. The obtained results demonstrated that the analytical method was successfully validated, with LOD values of 1.211, 0.606, and 1.816 µg/mL, and LOQ values of 3.670, 1.835, and 3.676 µg/mL. The assay displayed a linear range of 5–1000 µg/L concentration and was found suitable for further formulation content analysis.

Analytica doi: 10.3390/analytica6040041

Authors: Maxime Chivaley Samia Bassim Vicmary Vargas Didier Lartigue Brice Bouyssiere Florence Pannier

As one of the world’s most widely used packaging materials, paper obtains its properties from its major component: wood. Variations in the species of wood result in variations in the paper’s mechanical properties. The pulp and paper production industry is known to be a polluting industry and a consumer of a large amount of energy but remains an essential heavy industry globally. Paper production, based largely on the kraft process, is mainly intended for the food packaging sector and, thus, is associated with contamination risks. The lack of standardized regulations and the different analytical techniques used make information on the subject complex, particularly for inorganic elements where little information is available in the literature. Most research in this field is based on sample preparation using mineralization via acid digestion to obtain a liquid and homogeneous matrix, mainly with a HNO3/H2O2 mixture. The most commonly used techniques are Atomic Absorption Spectrometry (AAS), Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), each with its advantages and disadvantages, which complicates the use of these tech-niques for routine analyses on an industrial site. In the same field of inorganic compound analysis, Microwave Plasma Atomic Emission Spectrometry (MP-AES) has become a real alternative to techniques such as AAS or ICP-AES. This technique has been used in several studies in the food and environmental fields. This publication aims to examine, for the first time, the state of the art regarding the analysis of inorganic elements in food packaging and different matrices using MP-AES. The entire manufacturing process is studied to identify possible sources of inorganic contaminants. Various analytical techniques used in the field are also presented, as well as research conducted with MP-AES to highlight the potential benefits of this technique in the field.

Analytica doi: 10.3390/analytica6040040

Authors: Suhail Alghanem Ewelina Dziurkowska

(1) Background: Caffeine is one of the most widely consumed psychoactive substances. Its safety profile and short half-life make it an ideal drug model for studying the pharmacokinetics of caffeine. This study aimed to develop a method for determination of caffeine in a small volume of saliva (200 µL). (2) Methods: Solid-phase extraction was employed to isolate caffeine from saliva, followed by quantitative analysis using liquid chromatography coupled with diode-array detection. Chromatographic separation was achieved on a C18 column, using a gradient mobile phase of acetonitrile and 0.1% formic acid. (3) Results: The method was validated for selectivity, linearity, precision, and accuracy. Linearity was established over the range of 10–10,000 ng/mL (R2 = 0.995). The coefficients of variation for intra- and inter-day precision for the three tested caffeine concentrations did not exceed 12.11%. Recovery from spiked saliva samples exceeded 90.53%. The developed method was applied to preliminary studies to follow the pharmacokinetics of caffeine in saliva. The concentration of the substance was studied in the saliva obtained from a volunteer after espresso consumption. (4) Conclusions: The developed method will offer a reliable approach for non-invasive caffeine monitoring in clinical and research applications.

Analytica doi: 10.3390/analytica6040039

Authors: David Kleiner David Muscatiello Zugeily Gutierrez Vanessa Asare Yong Guo

Nucleosides are of significant interest to biomedical and pharmaceutical research and have been successfully separated in hydrophilic interaction liquid chromatography (HILIC). However, there have been few studies focusing on the retention mechanisms, and detailed retention mechanisms are not clearly understood. The quantitative assessment methodology based on the linear relationship between the observed retention factors and the phase ratio has been shown to be a new tool to investigate the retention mechanisms of polar compounds in HILIC. This study evaluated the retention mechanisms of 16 nucleosides on a bare silica column. The retention contributions by partitioning, adsorption, and electrostatic attractions are quantitatively determined, and the main retention mechanism can be unambiguously identified for each nucleoside. The study results indicate that the main retention mechanism can shift with the salt concentration in the mobile phase, but partitioning seems to dominate at higher salt concentrations. In addition, the partitioning coefficients are measured using the quantitative assessment methodology and have a relatively strong correlation with the log P values of the nucleosides. Considering large errors in the log P values for these very polar compounds, the partitioning coefficients measured experimentally in the HILIC system may provide a more accurate measure for polarity assessment.

Analytica doi: 10.3390/analytica6040038

Authors: Slađana V. Dončić Dragan Z. Troter Miroslav M. Sovrlić Nebojša D. Zdravković Aleksandar G. Kočović Miloš N. Milosavljević Milos Stepovic Emina M. Mrkalić Jelena B. Zvezdanović Dušica P. Ilić Sandra S. Konstantinović

Significant depletion of natural resources, coupled with increased environmental pollution resulting from the constant evolution of global industrialization, poses a considerable problem. Therefore, it is unsurprising that sustainable “green” chemistry and technology are gathering the worldwide scientific community, whose common goal is to find applicable solutions for the abovementioned problems. This paper combined the ultrasonic extraction method (a form of “green” technology) with natural deep eutectic solvents (NADESs, a type of “green” solvent) for the production of extracts from an industrial by-product (discarded waste wild apple dust). Waste wild apple dust was pretreated with different NADESs in order to explore the pretreatment benefits regarding ultrasonic extraction of bioactive compounds. Among all solvents used, aqueous propylene glycol was chosen as the best system, which, combined with Reline NADES pretreatment, provided the highest TPC and TFC values, together with the best antioxidant activities. UHPLC-DAD-MS analyses of extracts revealed the presence of natural organic acids, quercetin and kaempferol derivatives, tannins, and flavones. Following this procedure, valorization of agro-industrial apple herbal waste resulted in obtaining extracts with high potential for utilization in different industrial branches (food and pharmaceutical industries), contributing to both cleaner production and reduced environmental impact.

Analytica doi: 10.3390/analytica6030037

Authors: Piyanat Issarangkura Na Ayutthaya Chanchana Thanachayanont Khan-Un Thongdeevimornwong Tanagorn Sirisakulchaiyaporn Patinya Khummanee Nattawadee Wisitruangsakul Monnapat Vongboot

The synthesis of new molecularly imprinted polyurethane foam (MIPUF) using an herbicide of atrazine (Atz) as a template for selective solid-phase extraction for Atz was proposed for the first time. The MIPUF was simply synthesized under mild conditions, without requiring an oxygen-free environment. Some household apparatuses were adapted for the preparation, such as a plastic cup and bamboo chopstick. The ready-to-use MIPUF minicolumns could be obtained within 4 h with more than 10 minicolumns. The proposed material was characterized using FT-IR and SEM. The MIPUF minicolumn was used in a solid-phase extraction. The eluate of free Atz was determined using the fluorescence technique without further derivatization at 343 nm. The MIPUF offered a good sensitivity and selectivity over non-molecularly imprinted polyurethane foam (NIPUF), enhancing fluorescence intensity by 15.6 times. The linear equation and linear range for Atz detection at y = 87.25x + 311.58, R2 = 0.9887 and 0.2–1.0 µM were obtained. The LOD and LOQ were 35 and 110 nM, respectively. The MIPUF revealed a more selective Atz than some potential pesticides. The ready-to-use minicolumn has been used for sample preparation and Atz assays in surface water in orchards and river water samples with recoveries (%) at 90–110%.

Analytica doi: 10.3390/analytica6030036

Authors: Emrah Kirtil

Pesticide residue violations continue to challenge the compliance of Turkish horticultural exports with European Union food safety regulations. This study examined 1138 RASFF alerts (1660 detections) issued between 2020 and 2025 using statistical enrichment, time-series modeling, and unsupervised machine learning. Pepper was the most frequently rejected commodity, with strong enrichments of formetanate (71-fold), pyridaben (35-fold), and acetamiprid (5-fold). Notably, chlorpyrifos and chlorpyrifos-methyl remained among the most commonly detected residues despite EU bans, suggesting continued use of stockpiled or illicit products and prolonged environmental persistence. Rejections peaked during winter and spring, particularly for citrus and greenhouse-grown crops. Clustering and association rule mining revealed modular commodity–pesticide structures and recurrent co-detection patterns. Anomaly detection further identified discrete periods of irregular contamination. Overall, the results indicate that violations are seasonally patterned and structurally embedded. Targeted monitoring aligned with crop calendars and stricter enforcement of legacy pesticide phase-outs could significantly improve compliance and reduce export rejections.

Analytica doi: 10.3390/analytica6030035

Authors: Heru Agung Saputra Demas Aji Badrut Tamam Ibnu Ali Asranudin

Fundamental research, exploration, extraction, and metallurgical studies of rare earth elements (REEs) require the use of analytical techniques. Recently, emerging developments of analytical instrumentation for REEs have taken place, with some of them having shrunk in size, becoming handheld devices. The Flame and Graphite Furnace AAS, ICP-OES, and MP-AES are standard laboratory techniques used for the analysis of REEs. ICP-MS, ICP-MS/MS, ICP-TOF-MS, HR-ICP-MS, MH-ICP-MS, and MC-ICP-MS are popular techniques for REE analysis thanks to their ultrahigh sensitivity, minimal interference effects, and broad applicability. The INAA, XRF, LIBS, and LA-based ICP-MS techniques are widely employed for the direct analysis of solid samples. The TIMS, SIMS, and SHRIMP are common techniques used for dating isotopic REE deposits. The portable XRF, LIBS, and Raman spectrometer devices can perform on-the-spot in situ analysis, which may help make speedy decisions in the exploration study of REEs. Currently, hyperspectral remote sensing platforms, such as handheld, drone, and satellite-based devices, are preferred for the exploration of REEs due to their cost-effectiveness, which enables the coverage of large areas in a limited amount of time. The use of microanalytical sensors installed on remotely operated vehicles has been successfully applied in analyzing rich REE-bearing deposits in the deep sea. In general, this review provides in-depth information on all essential aspects, from analytical instruments to cutting-edge developments in the analysis of REE-bearing resources.

Analytica doi: 10.3390/analytica6030034

Authors: Maria Tarapoulouzi Małgorzata Ruggiero-Mikołajczyk Ioannis Pashalidis Charis R. Theocharis

Halloumi cheese, a traditional Cypriot dairy product with Protected Designation of Origin (PDO) status, is renowned for its unique texture and high melting point. PDO certification is crucial for Halloumi cheese as it ensures the product’s authenticity, protects its traditional production methods and geographical origin, and safeguards consumers and producers against fraud and mislabeling. However, concerns over adulteration, particularly through the addition of skim milk powder, pose challenges to its authenticity and quality control. This study is the first to analyze Halloumi cheese using Brunauer–Emmett–Teller (BET) analysis and Fourier Transform Infrared (FTIR) spectroscopy, providing a novel approach to assessing its composition and authenticity. Furthermore, it marks the first time Halloumi samples have been examined in the context of PDO certification. Alongside PDO-certified Halloumi, two additional sample sets were produced following PDO specifications for moisture, fat, and salt content, with the controlled incorporation of skim milk powder as an adulterant at concentrations of 1% and 5%. Principal component analysis (PCA) was employed to visualize and interpret the spectral data, revealing promising results. Chemometric analysis showed that the specific surface area from BET measurements and the FTIR spectral subregion between 1650 and 1100 cm−1 were key factors, and they were retained for model construction. These findings could play a crucial role in establishing official food fraud detection methodologies, particularly for the Cyprus and EU markets. While this study serves as an initial investigation, additional samples will be tested in future studies to validate these preliminary results and to assess the potential of applying these techniques in real-world food fraud detection scenarios.

Analytica doi: 10.3390/analytica6030033

Authors: Saulo Alves de Souza Cristiane dos Reis Feliciano Grazielle Cabral de Lima Ítalo Agnis da Silva Gomes Nathália Carvalho Costa Bruno Alves Rocha Mariane Gonçalves Santos

The contamination of food and beverages with heavy metals, such as Cd, presents significant health risks, underscoring the need for reliable and sensitive analytical methods. This study introduces the development of a rapid, cost-effective, and environmentally friendly method for Cd determination in cachaça, a traditional Brazilian sugarcane spirit. Magnetic nanoparticles (Fe3O4) functionalized with tetraethyl orthosilicate are synthesized and employed as adsorbents in a dispersive magnetic solid-phase extraction procedure. The extracted Cd is quantified using flame atomic absorption spectrometry. A full factorial experimental design is used to optimize key parameters, including the sorbent mass, adsorption time, desorption time, and acid concentration. The method demonstrates excellent analytical performance, with a linear calibration range (R2 = 0.99), detection limit of 0.0046 mg L−1, and quantification limit of 0.0200 mg L−1. Moreover, validation results show high precision (coefficient of variation < 9.10%) and accuracy (recovery rates between 92.00% and 120.00%). When analyzing commercial cachaça samples, cadmium was detected in all five specimens. Notably, in one sample the cadmium concentration exceeded Brazil’s maximum permissible limit of 0.0200 mg kg−1, underscoring the importance of this work for ensuring food safety. The proposed method offers a sensitive, reproducible, and sustainable approach for analysis of potentially toxic trace metals in alcoholic beverages, reinforcing its potential for routine monitoring and regulatory compliance.

Analytica doi: 10.3390/analytica6030032

Authors: Dritan Topi Hasim Kelebek Gazmend Shehi Gamze Guclu Serkan Selli

Merlot red wines rank among the most distinguished varietals globally. This study aimed to characterize the phenolic compound profiles of Merlot wines and assess the influence of geographical origin and vintage on samples from two Albanian wine regions. Using liquid chromatography coupled with tandem mass spectrometry, a total of 31 phenolic compounds were identified and quantified. These were classified into hydroxybenzoic acids and flavan-3-ols (13 compounds), phenolic acids (9), flavonols (5), and stilbenoids (4). The total phenolic content ranged from 294 mg L−1 in wines from the Mati–Mirdita region to 480 mg L−1 in those from the Durrës–Kavaja region, demonstrating significant regional variation. Notably, the hydroxybenzoic acids and flavan-3-ols exhibited the most pronounced differences, with gallic acid concentrations varying from 123 mg L−1 (Mati–Mirdita) to 170 mg L−1 (Durrës–Kavaja). Both regions’ wines were rich in catechin, epicatechin, procyanidin derivatives, trans-caftaric acid, and ethyl gallate. However, procyanidins were found in higher concentrations in the Mati–Mirdita wines, while other phenolics were more abundant in Durrës–Kavaja samples. These findings underscore the influence of geographical and climatic factors on phenolic composition, offering a robust chemical fingerprinting approach for assessing wine authenticity and quality.

Analytica doi: 10.3390/analytica6030031

Authors: Angel Nikolov Nely Grozeva Miroslav Vasilev Daniela Orozova Zlatin Zlatev

The growing demand for functional bakery products necessitates research on the enrichment of wheat bread with pigweed (Amaranthus spp.) and purslane (Portulaca oleracea) flour. Although these plant-based raw materials offer nutritional and environmental benefits, their inclusion in wheat bread formulations poses challenges in the creation of formulations that may compromise the sensory and structural qualities of the final product. The main objective of this work is to systematically determine the optimal amounts of these alternative flour using multimodal bread characterization techniques that include physicochemical, organoleptic, geometric, and optical evaluations, supported by advanced data reduction techniques and regression models. A total of 70 features were analyzed and reduced to 22 for pigweed flour and 15 for purslane flour informative features. Predictive models (R2 = 0.85 for pigweed flour, R2 = 0.84 for purslane flour) were developed to optimize the inclusion of alternative flour, resulting in appropriate concentrations of 3.69% for pigweed flour and 7.13% for purslane flour. These formulations balance improved nutritional profiles with acceptable sensory and structural properties. The results obtained not only complement the potential of pigweed and purslane as sustainable functional raw materials but also demonstrate the efficacy of an automated, image-based approach to formulating recipes in food manufacturing.

Analytica doi: 10.3390/analytica6030030

Authors: Najlae El Bouanani Bouchaib Bencharki Hafsa Houmairi

This study analyzes the nutritional quality and mycotoxin contamination of three key feed ingredients—corn, soybean meal (SBM), and sunflower meal (SFM)—imported into Morocco during the years 2019, 2020, and 2021. Samples were collected upon reception at the plant and analyzed in triplicate under standardized laboratory conditions. Chemical composition was evaluated using classical and NIR-based methods, while mycotoxin levels were assessed through ELISA and confirmed by HPLC. Corn samples from Argentina, Brazil, and Ukraine were assessed for their proximate composition and mycotoxin burden. While most nutritional parameters showed no significant differences between origins (p > 0.05), water activity (Aw) and digestible threonine content were significantly affected by origin (p < 0.01). Brazilian corn had the highest Aw (0.716), followed by Argentina (0.680), and Ukraine (0.662), a factor linked to its higher susceptibility to mold and mycotoxin development. Soybean meal from the U.S. and Argentina showed a general positive trend in favor of U.S. imports, with higher average crude protein (the CP content of American soybean meal was 46.912%, compared to 46.610% in Argentine soybean meal), fat, digestible lysine, and metabolizable energy. However, statistical differences were limited to water activity and moisture content (p < 0.05). American soybean meals are generally recognized for their consistent processing quality and superior amino acid digestibility. Sunflower meal, sourced exclusively from Ukraine, showed a steady improvement in crude protein (from 35.97% in 2019 to 36.99% in 2021) and metabolizable energy, alongside reduced crude fiber content, enhancing its nutritional value in poultry diets. The consistent use of Ukrainian SFM in Morocco reflects both supply stability and quality. Regarding mycotoxins, origin had a significant effect on several compounds. Argentine and Brazilian corn showed higher mean levels of fumonisins (1165.26 and 1019.52 ppb), ochratoxin A (2.26 and 3.02 ppb), and zearalenone (36.99 and 21.92 ppb) compared to Ukrainian corn, which consistently had the lowest levels across all major mycotoxins (e.g., fumonisins = 200 ppb; zearalenone = 4.90 ppb). Aflatoxin B1 levels remained constant at 0.2 ppb across all origins. These findings confirm the influence of geographic origin—particularly water activity—on mycotoxin risk in imported maize.

Analytica doi: 10.3390/analytica6030029

Authors: Jinan Sabsabi Andressa Adame Francis Vanier Nii Patterson Allan Feurtado Aïssa Harhira Mohamad Sabsabi François Vidal

Rapid and accurate assessment of nutritional quality, particularly crude protein content and essential nutrient concentrations, remains a major challenge in the food and feed industries. In this study, laser-induced breakdown spectroscopy (LIBS) was combined with advanced chemometric modeling to predict the levels of crude protein and key macro- and micronutrients (Ca, Mg, K, Na, Fe, Mn, P, Zn) in 61 barley forage samples composed of whole aerial plant parts ground prior to analysis. LIBS offers a compelling alternative to traditional analytical methods by enabling real-time analysis with minimal sample preparation. To minimize interference from atmospheric nitrogen, nitrogen spectral lines were excluded from the protein calibration model in favor of spectral lines from elements biochemically associated with proteins. We compared the performance of Partial Least Squares (PLSR) regression and Extreme Learning Machine (ELM) using fivefold cross-validation. ELM outperformed PLS in terms of prediction, achieving a coefficient of determination (R2) close to 1 and a ratio of performance to deviation (RPD) exceeding 2.5 for proteins and several nutrients. These results underscore the potential of LIBS-ELM integration as a robust, non-destructive, and in situ tool for rapid forage quality assessment, particularly in complex and heterogeneous plant matrices.

Analytica doi: 10.3390/analytica6030028

Authors: Julia D. Bryantseva Marina O. Gorbunova Vladimir A. Zhinzhilo Igor E. Uflyand

The reaction of zirconium tetrachloride with 2-amino-1,4-benzenedicarboxylic acid in N,N-dimethylformamide with the addition of HCl leads to the formation of zirconium 2-amino-1,4-benzenedicarboxylate. Zirconium 2-amino-1,4-benzenedicarboxylate was characterized by elemental analysis, infrared spectrometry, X-ray diffraction, scanning electron microscopy, and volumetric nitrogen adsorption/desorption. The sample has a constant porosity with an average pore diameter of 7.97 nm and both microporous and mesoporous structure with a large surface area (820 m2/g) corresponding to the type IV adsorption. Zirconium 2-amino-1,4-benzenedicarboxylate was used for solid-phase extraction (SPE) of chlortetracycline hydrochloride from the aqueous solution. The obtained results confirmed the possibility of using the proposed analytical technique as a new, convenient approach to the extraction of chlortetracycline hydrochloride from industrial or other wastewaters, where such substance is contained in insignificant concentrations and its determination requires expensive and complex equipment. In the future, this method can be used not only for the effective removal of pollutants from industrial wastewater with subsequent regeneration of the sorbent, but also as a sample-preparation method for concentrating chlortetracycline hydrochloride from dilute solutions with its subsequent elution and analysis by available methods, for example, spectrophotometry, since the limit of detection is 0.06 mg/L. Experimental data are described by the isotherm of SPE (R2 = 0.998–0.999) and show the ability of zirconium 2-amino-1,4-benzenedicarboxylate to extract up to 578 mg/g of sorbent at 5 °C under optimal conditions.

Analytica doi: 10.3390/analytica6030027

Authors: Merle Käberich Lisann Nemetz Frank Sacher

Melamine (MEL) has broad applications and can be released to the aquatic environment from various sources, including industry, agriculture, traffic, and household articles. In addition, MEL derivatives ammeline (AMN), ammelide (AMD), and cyanuric acid (CYA) as well as potential precursors cyromazine (CYRO) and hexa(methoxymethyl)melamine (HMMM) are relevant related substances. However, occurrence and transformation in water resources has not yet been thoroughly investigated. Here, we developed a sensitive analytical method for quantification of these analytes by hydrophilic interaction liquid chromatography (HILIC) coupled to tandem mass spectrometry (MS/MS). Direct injection achieved limits of quantification (LOQs) of 0.1 µg/L (AMN 0.2 µg/L; CYA 1 µg/L), while LOQs could be improved to 0.01 µg/L (CYA 0.05 µg/L) by applying evaporation for analyte pre-concentration. The method was extensively validated, showing good recovery, repeatability, and linearity. The evaluation of the matrix effects revealed method applicability for various water matrices, including surface water and wastewater. During proof-of-concept measurements, HMMM in combination with MEL and its derivatives was found in multiple samples, emphasizing the importance of including precursors. In the future, the developed method with its novelty of covering both MEL derivatives and precursors can be applied for comprehensive monitoring programs elucidating MEL sources and transformation in water resources.

Analytica doi: 10.3390/analytica6030026

Authors: Yolisa A. Lucwaba Khakhathi L. Mandiwana

Cement manufacturing is the second largest anthropogenic source of Hg emissions in the environment. Therefore, the establishment of analytical methodologies that can be utilized in the determination of Hg concentration from cement raw materials and cement is of great importance. The total Hg and Hg thermospecies in cement raw materials and cements were determined by thermal desorption techniques with a Zeeman Hg analyzer. No chemical pre-treatment of samples is required for this technique prior to analysis. An optimum single-stage temperature program was applied to determine total Hg at an optimum heating rate of approximately 5 °C s−1 while Hg thermospecies were determined over four stages at an optimum heating rate of approximately 0.2 °C s−1 per stage from ambient temperature to 720 °C. Total mercury concentrations in cement raw materials ranged between 2.19 ng g−1 and 395 ng g−1, while in cement, concentrations ranged between 1.32 ng g−1 and 31.0 ng g−1. The highest Hg contents were found in dust return (580 ng g−1 and 679 ng g−1). Hg thermospecies determination showed that cement raw materials and cements contain one Hg thermospecies that is released at 20–180 °C while dust return contained one to four Hg thermospecies that could be released at 20–180 °C, 180–360 °C, 360–540 °C, and/or 540–720 °C, thus indicating that new Hg compounds are formed during cement production.

Analytica doi: 10.3390/analytica6030025

Authors: Fotouh R. Mansour Marcello Locatelli Alaa Bedair

The Stability Toolkit for the Appraisal of Bio/Pharmaceuticals’ Level of Endurance (STABLE) is introduced and proposed as a comprehensive tool and software to evaluate the stability of active pharmaceutical ingredients (APIs) under various stress conditions. In the pharmaceutical industry, stability testing is a critical step in the drug development process, ensuring the quality, safety, and efficacy of APIs. Traditional stability tests—such as real-time, accelerated, and forced degradation testing—often face challenges, including inconsistent interpretation and implementation across different regions and organizations. STABLE addresses these challenges by providing a standardized and holistic approach to assessing drug stability across five key stress conditions: oxidative, thermal, acid-catalyzed hydrolysis, base-catalyzed hydrolysis, and photostability. Beyond its role as an evaluation tool, STABLE also serves as a practical guide for chemists, encouraging a more complete and thoughtful approach to stability studies. While many investigations focus solely on acid- and base-catalyzed hydrolysis, other critical conditions—such as photostability—are often underexplored or entirely omitted. By highlighting the importance of evaluating all relevant degradation pathways, STABLE promotes more robust and informed stability testing protocols. The index utilizes a color-coded scoring system to quantify and compare stability, facilitating consistent assessments across different APIs. This paper discusses the methodology of STABLE, including the scoring system and specific criteria applied under each condition. This tool is introduced to reflect intrinsic degradation susceptibility under forced conditions. The software is freely available as an open-source tool at bit.ly/STABLE2025, enabling broader accessibility and implementation across the pharmaceutical research community.

Analytica doi: 10.3390/analytica6030024

Authors: Cielo Urquijo Mauricio Maldonado

The dichromate ion (Cr2O72−), a highly toxic chromium VI species, is widely used in industrial processes, generating serious environmental problems when released into water bodies. This investigation proposes the use of a functionalized polymer as an adsorbent material for its removal in the aqueous phase. Poly(butyl methacrylate) (PBMA) was synthesized and modified by impregnation with resorcinarenes derived from long-chain aliphatic aldehydes. To improve the affinity for the dichromate, the resorcinarenes were functionalized with sulfomethyl groups by treatment with Na2SO3. The resulting matrices were characterized using IR-ATR, 1H-NMR, and 13C-NMR, and their adsorbent performance was evaluated via UV-Vis spectroscopy in batch extraction assays. The results showed that the functionalized polymer exhibited a higher adsorption capacity than the base polymer, reaching up to 81.1% removal at pH 5.0 in one hour. These results highlight the potential of PBMA as an effective support and raise a promising research perspective for functionalized resorcinarenes in the development of new materials for the treatment of contaminated water.

Analytica doi: 10.3390/analytica6030023

Authors: Margarita A. Tokareva Evgeny S. Melnikov Elizaveta N. Fisher Tatiana A. Rodina Igor E. Shohin Maria V. Belova

The application of high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) in the analysis of peptide therapeutics demonstrates its capacity to achieve high sensitivity and selectivity, which are essential qualities for the expanding peptide therapeutic industry. Given the challenges posed by hydrophilic peptides in reversed-phase chromatography, we investigated the necessity of a derivatization procedure to improve chromatographic separation and quasimolecular ion fragmentation during MS/MS detection. We investigated how eight different derivatizing agents react with a hydrophilic lysine- and arginine-containing human ezrin peptide-1 (HEP-1) to identify the most suitable one. The results showed that the reaction of HEP-1 with propionic anhydride proceeds most rapidly and completely, providing a high and reproducible yield of the product, which has sufficient retention on the RP column. The 4-propionylated derivative of HEP-1, compared to the other derivatives considered, demonstrates the most pronounced MS/MS fragmentation. The retention time of 2.42 min allows the separation of the substance from the interfering components of the blood plasma matrix and provides a limit of quantification of 5.00 ng/mL, which allows the use of this derivatizing agent for subsequent applications in pharmacokinetic studies, and this approach can improve the analytical parameters of similar peptides in other HPLC-MS/MS studies.

Analytica doi: 10.3390/analytica6030022

Authors: Valvanuz Cahuantzi Rosalba Patiño Herrera Norma Verónica Zavala Alonso Daniela Salado Leza María Selene Berber Mendoza Elías Pérez

This study focuses on the stabilization of a natural hair dye derived from Lawsonia inermis L. (henna) and Indigofera suffruticosa (indigo). Although various formulations already exist, they are designed for immediate use and cannot be stored. Lawsonia, a primary component of the dye, tends to degrade after release. To ensure its stability, freeze-drying was implemented as a protective measure. Colorimetric analysis confirmed the dye’s ability to maintain an intense, uniform coloration even after multiple washing cycles. Stability tests demonstrate that freeze-drying effectively enhances the dye’s stability and capacity to retain its physical properties and color under various environmental conditions, demonstrating its potential for long-term use. The dye’s pH (5.05) aligns with the natural pH of hair, promoting cuticle sealing and improving hair health. Cytotoxicity tests confirmed the dye’s safety, showing no harmful effects. Gray hair exhibited a total color difference (ΔE) of 64.06 after the initial application, using natural gray hair as a reference. By the third application, ΔE increased to 69.86 and gradually decreased to 68.20 after 15 washing cycles, highlighting its long-term durability. Gray hair exposed to 720 h of UV radiation showed a ΔE of 17.34, whereas dyed gray hair exhibited a ΔE of 2.96 compared to non-UV-exposed samples. This indicates superior resistance to color degradation in dyed hair. Also, SEM imaging revealed the dye’s restorative effects, progressively improving hair cuticle structure with each application.

Analytica doi: 10.3390/analytica6020021

Authors: Eliabe Sousa da Silva Jorge Machado Freitas João Pedro Cezário Brandão Ivana Ferreira Simões Alexandre Rafael Lenz Mariana de Paula Drewinski Ágata Carvalho Morais Nelson Menolli Aníbal de Freitas Santos

Edible mushrooms are macroscopic fungi that have been recognized as the “new superfoods” due to their high nutritional and medicinal values. The aim of this study was to develop and optimize a method for the wet digestion of edible mushrooms using a closed digestion block for the determination of macro- and micronutrients (Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, and Zn) using microwave-induced plasma emission spectrometry (MIP OES). For the digestion of the samples, a 23 factorial design was used to evaluate the amount of HNO3 65% (m m−1), H2O2 30% (m m−1) and the digestion time, in 500 mg of the sample (dry and crushed) at 200° C. The method was applied to eleven species of edible or medicinal mushrooms (edible cultivated from wild strains, wild edible, and commercials medicinal). The average concentrations (in mg kg−1) showed higher levels of K (1442.85–17,534.97), Mg (1295.40–13,550.72), Fe (11.33–27.38), Zn (28.86–36.09), and Mn (10.22–10.97). This study contributed to the determination of the multi-element composition and nutritional potential of edible mushrooms from Brazil.

Analytica doi: 10.3390/analytica6020020

Authors: Daniel Hernández-Ramírez Carlos Ríos-Martínez José Luis Pinedo-Vega Fernando Mireles-García Fernando De la Torre Aguilar Edmundo Escareño-Juárez

This study investigated the spatial distribution and radiological risks of naturally occurring radionuclides (226Ra, 232Th, 40K) in 37 soil samples from Zacatecas, located in north-central Mexico, using high-resolution gamma spectrometry. Results revealed 40K concentrations (mean: 736.81 Bq kg−1), nearly double the global average, while 226Ra (29.96 Bq kg−1) and 232Th (29.72 Bq kg−1) aligned with worldwide norms. Geoaccumulation indices identified moderate 40K accumulation at 22 sites, with El Capulín classified as moderately contaminated (Igeo = 1.07). Radiological risk indices showed absorbed dose rates (62.52 nGy h−1) and excess lifetime cancer risk (0.330 × 10−3) exceeding global thresholds by 4% and 14%, respectively. Multivariate analyses demonstrated strong Spearman correlations (ρ = 0.75–1.00) among risk indices, while spatial interpolation identified southern/western regions as high-risk zones. These findings emphasize the necessity of integrating spatial analysis with multivariate statistical techniques in environmental radioprotection frameworks. While most of the study area complies with international safety standards, the identified zones exceeding dose thresholds warrant prioritized management to mitigate potential cumulative health risks.

Analytica doi: 10.3390/analytica6020019

Authors: Antonella Maria Aresta Giovanna Mancini Nicoletta De Vietro Carlo Zambonin

A solid phase microextraction (SPME) method coupled with liquid chromatography (LC) and fluorescence/ultraviolet-diode array detection was developed for the simultaneous determination of quercetin and trans-resveratrol. The chromatographic, detection, and SPME extraction/desorption conditions were systematically optimized. The performance of four commercial SPME fibers—polyacrylate (PA), polyethylene glycol (PEG), polydimethylsiloxane (PDMS), and polydimethylsiloxane-divinylbenzene (PDMS-DVB)—was evaluated and compared with a homemade polydopamine (PDA)-coated fiber. While all of the fibers successfully extracted the target analytes, their efficiencies varied significantly. The PA, PEG, and PDA fibers demonstrated superior performance, exhibiting wide linearity ranges (0.03–1 µg/mL (PA and PEG) and 0.06–1 µg/mL (PDA) for quercetin, 0.01–1 µg/mL for trans-resveratrol); high sensitivity (LODs of 0.01 µg/mL (PA and PEG) and 0.02 µg/mL (PDA) for quercetin, 0.003 µg/mL for trans-resveratrol); and excellent precision. Among these, the polyacrylate coating delivered the best analytical performance and was selected for further application. The optimized method was applied to analyze winemaking by-products (seeds, skins, and stalks) using SPME on ethanol-macerated extracts subjected to brief ultrasonication. Quercetin and trans-resveratrol were quantified in pomace extracts at concentrations of 104.3 ± 8.2 µg/g and 38.5 ± 4.1 µg/g, respectively. Recovery experiments confirmed the method’s accuracy, with recoveries of 99.1 ± 7.4% for quercetin and 98.5 ± 9.8% for trans-resveratrol. This study establishes a reliable, sensitive, and efficient approach for the determination of these bioactive compounds in complex matrices, with potential applications in the food and pharmaceutical industries.

Analytica doi: 10.3390/analytica6020018

Authors: Sophia R. Ginet Frank Gonzalez Maxine L. Marano Megha D. Salecha Joseph E. Reiner Gregory A. Caputo

Early detection of cancer can dramatically improve long-term prognosis and survivability in a variety of different cancer types. However, for many cancer types, the ability to effectively detect early-developing tumors is challenging, especially in physiological locations with limited visibility or access. Previously, we reported a sensing platform and methodology to detect biomarker peptides found in urine from ovarian cancer patients. This sensing platform relies on peptide interactions with gold nanoclusters through thiol-mediated linkages; thus, the sensitivity of the biomarker assay is directly related to appropriate redox states of the biomarkers in question. Here, we report on an expansion of the traditional thiol-reactivity assay originally developed by Ellman to include and evaluate a variety of solution modifications that may be used in conjunction with the biomarker-sensing platform. Because biomarker peptides may be isolated from a variety of biological tissues or fluids, depending on the target condition or disease, we screened numerous solution conditions that may be directly used in sample preparation and peptide extraction. The data demonstrate that the assay maintains linearity under these various conditions. The assay was then applied to a variety of models and biomarker peptides and exhibits the expected linear response. These results demonstrate the applicability of the thiol-reactivity assay to biologically derived samples, and the flexibility to ensure sample preparation and treatment will retain the appropriate sample redox conditions to ensure optimal interactions with the biosensor platform. It also facilitates the ability to perform quality control on clinically derived biological samples to ensure appropriate preparations, and concentrations are available for application to the nanopore biosensor platform.

Analytica doi: 10.3390/analytica6020017

Authors: Enrico Greco

Over the past decade, more than a thousand new psychoactive substances (NPSs) have emerged worldwide. This rapid proliferation of “designer drugs” poses significant challenges for drug control, forensic analysis, and public health. Artificial intelligence (AI) has increasingly been applied to address these challenges in NPS design and analysis. This review provides a comprehensive overview of AI methodologies—including deep learning, generative models, and quantitative structure–activity relationship (QSAR) modeling—and their applications in the synthesis, prediction, and identification of NPSs. We discuss how AI-driven generative models have been used to design novel psychoactive compounds and predict their pharmacological activity, how QSAR models can forecast potency and toxicological profiles, and how machine learning is enhancing analytical chemistry workflows for NPS identification. Special emphasis is placed on mass spectrometry (MS)-based techniques, where AI algorithms (e.g., for spectral prediction and pattern recognition) are revolutionizing the detection and characterization of unknown NPSs. A dedicated section examines the legal and regulatory implications of AI-generated psychoactive substances in the European Union (EU) and United States (USA), highlighting current policies, potential gaps, and the need for proactive regulatory responses. The review concludes with a discussion of the benefits and limitations of AI in this domain and outlines future directions for research at the intersection of AI, analytical chemistry, and drug policy.

Analytica doi: 10.3390/analytica6020016

Authors: Nassima Boutaoui Meryem Acila Nesrine Lariche Redouane Lemoui Asma Khellafi Cristina Campestre Francesco Melfi Marcello Locatelli

The objective of this work is to study the anti-inflammatory effect in vitro and in vivo of microwave (MW) extracts of Thymus algeriensis. The in vitro study was performed by the human red blood cell protection test, while the in vivo study used the carrageenan-induced rat paw edema model. The experimental results were confirmed by a molecular docking calculation. The results indicated that all the microwave extracts have a moderate anti-inflammatory effect, depending on their richness in phenolic compounds. Among the extracts studied, the one obtained at 100 °C for 15 min exhibited the most pronounced anti-inflammatory effect, with an inhibition of 78.52%, which is attributed to its high flavonoid content. In particular, the flavonoids naringin and catechin showed the best affinity for the target protein, with values of −10.3 kcal/mol and −9.2 kcal/mol, respectively, as well as low inhibition constants of 0.028 μM and 0.18 μM. These results indicate that these flavonoids generate interactions that enhance the stability of the target ligand–protein complex, thus contributing to the observed anti-inflammatory effect.