Search Results (2,242)

Extraction of metal ions from polluted waters and immobilization of metals in contaminated soils can be conducted using zeolites—porous aluminosilicate ion exchangers. The uptake of copper and zinc ions by the Georgian natural heulandite was studied under conditions of interaction of the zeolite with solutions (“liquid-phase” ion exchange) and powders (“solid-state” ion exchange) of the corresponding salts. The aim of the study was to compare the effect of the two procedures on the chemical composition and structure of the zeolite. It was found that the “liquid-phase” procedure provides a higher degree of uptake, particularly of zinc ions. Ion-exchange causes slight dealumination without decationization. Uptake of divalent ions occurs mainly through the leaching of sodium ions. According to X-ray data of ion-exchanged samples, the uptake of copper and zinc does not change the crystal structure of the zeolite framework, but nitrogen adsorption measurements show that ion exchange affects the mesoporous structure: solution treatment reduces the specific total pore volume and leads to the appearance of pores with a diameter of 4 nm. The “solid-state” procedure leads to an increase in specific total pore volume mainly due to an increase in the number of relatively small nanosized pores. Full article

The increasing use of reclaimed wastewater in agriculture raises growing concerns about the accumulation of priority organic micropollutants in edible crops. In this study, we developed and validated a novel QuEChERS–SPME–GC/MS method for the simultaneous determination of 15 polycyclic aromatic hydrocarbons (PAHs), 3 nitro-PAHs, and 14 polychlorinated biphenyls congeners in Eruca vesicaria (rocket) leaves. The method was optimized to address the matrix complexity of leafy vegetables and included a two-step dispersive solid-phase extraction (d-SPE) cleanup and aqueous dilution prior to SPME. Validation showed excellent performance, with MDLs between 0.1 and 6.7 µg/kg, recoveries generally between 70 and 120%, and precision (RSD%) below 20%. The greenness of the protocol was assessed using the AGREE metric, yielding a score of 0.60. Application to rocket samples irrigated with treated wastewater revealed no significant accumulation of target pollutants compared to commercial samples. All PCB and N-PAH congeners were below detection limits, and PAH concentrations were low and mostly limited to lighter compounds. Human health risk assessment based on toxic equivalent concentrations confirmed that estimated cancer risk (CR) values 10⁻⁹–10⁻⁸ were well below accepted safety thresholds. These findings support the safe use of reclaimed water for leafy crop irrigation under proper treatment conditions and highlight the suitability of the method for trace-level food safety monitoring. Full article

A comprehensive UPLC-MS/MS method was developed and validated for the simultaneous separation and quantification of atenolol, propranolol, quinidine, and verapamil, using established intestinal permeability standards in the Caco-2 cell monolayer model. This in vitro model is widely accepted for predicting intestinal drug permeability and is formally recognized by global regulatory agencies, including the FDA, EMA, and WHO, as a surrogate for assessing drug permeability in biowaiver applications under the Biopharmaceutics Classification System (BCS) framework. Despite its regulatory importance, standardized methods for the simultaneous quantification of key permeability markers remain scarce. The selected compounds represent distinct transport pathways: paracellular (atenolol), passive transcellular (propranolol, verapamil), and P-glycoprotein-mediated efflux (quinidine). Method validation followed FDA guidelines and demonstrated high selectivity, linearity (r² > 0.998), precision, and accuracy. Solid-phase extraction enhanced recovery and reduced matrix effects. Application to Caco-2 permeability assays confirmed expected transport profiles, including P-gp inhibition effects with verapamil. By integrating multiple analytes in a single workflow, the method improves analytical throughput, supports mechanistic interpretation, and ensures consistency across assays. This advanced separation strategy, combined with sensitive mass spectrometric detection, supports regulatory and BCS-based classification studies, contributing to the standardization of permeability assessments in drug development. Full article

An innovative ultrasound-assisted deep eutectic solvent-based three-phase partitioning (UA-DES-TPP) system was developed for the sustainable extraction of Ficus carica polysaccharide (FCP). Using a hydrophobic DES composed of dodecanoic acid and octanoic acid (1:1 molar ratio), a phase behavior-driven separation mechanism was established. The system was systematically optimized through single-factor experiments and response surface methodology (RSM), achieving a maximum FCP yield of 9.22 ± 0.20% under optimal conditions (liquid–solid ratio 1:24.2 g/mL, top/bottom phase volume ratio 1:1.05 v/v, ammonium sulfate concentration 25.8%). Structural characterization revealed that FCP was a heteropolysaccharide primarily composed of glucose and mannose with α/β-glycosidic linkages and a loose fibrous network. Remarkably, the DESs demonstrated excellent recyclability over five cycles. Furthermore, FCP exhibited significant concentration-dependent antioxidant activities: 82.3 ± 3.8% DPPH radical scavenging at 8 mg/mL, 76.8 ± 0.8% ABTS⁺ scavenging, and ferric ion reducing power of 45.53 ± 1.07 μmol TE/g. This study provides a new path for the efficient and sustainable extraction of bioactive macromolecules. Full article

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. Full article

Aryl diazonium salt chemistry offers a robust and versatile approach for the modification of material surfaces via the covalent immobilization of reactive functional groups under mild conditions. In this study, this strategy was successfully applied to graft the chelating agent 4-(2-pyridylazo)resorcinol (PAR) onto Amberlite XAD-4 resin. Initially, 4-nitrobenzenediazonium tetrafluoroborate (NBDT) was covalently anchored onto the resin surface using hypophosphorous acid as a reducing catalyst to introduce aryl nitro groups. These nitro groups were subsequently reduced to aniline functionalities, enabling diazo coupling with PAR. The successful modification of the resin was confirmed by ATR-FTIR spectroscopy, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The synthesized chelating resin exhibited sorption capacities of 0.152, 0.167, and 0.172 mM g⁻¹ for Co(II), Ni(II), and Cu(II), respectively. The functionalized resin was packed into standard SPE cartridges and employed as a selective sorbent for the extraction and preconcentration of trace metals from groundwater samples collected from Dhalamah Valley, Al-Madinah Al-Munawwarah, prior to quantification by inductively coupled plasma mass spectrometry (ICP-MS). These results demonstrate the effectiveness of rapid diazonium-based surface functionalization for the preparation of selective polymeric metal chelators suitable for the extraction of trace metals from complex groundwater matrices. Full article

Due to the nearly identical chemical properties of Lu and Yb, the production of no-carrier-added (NCA) ¹⁷⁷Lu faces significant challenges in their separation. Achieving efficient and streamlined separation of Lu and Yb is crucial for the production of NCA ¹⁷⁷Lu. This study systematically investigated the separation performance of the commercial Rext-P350 extraction resin for Lu and Yb. Static adsorption experiments revealed that, at a solid–liquid ratio of 8 g/L, both Lu³⁺ and Yb³⁺ were nearly completely adsorbed, with saturation adsorption capacities of 25.8 mg/g and 21.5 mg/g, respectively. An increase in the nitric acid concentration in the aqueous phase significantly inhibited adsorption, but the separation factor for Lu³⁺/Yb³⁺ remained above 1.88. The adsorption kinetics followed a pseudo-second-order model (R² > 0.99), with equilibrium reached within 15 min, demonstrating fast adsorption kinetics. Characterization by SEM, FT-IR, and XPS confirmed the chemical coordination between the resin and Lu³⁺/Yb³⁺. Dynamic chromatographic separation experiments showed that the Rext-P350 resin exhibited significantly better separation performance for Lu³⁺/Yb³⁺ compared to 2-ethylhexylphosphoric acid mono-2-ethylhexyl ester (P507) extraction resin. Leveraging the excellent performance of Rext-P350 resin, a two-stage continuous extraction chromatography process was designed, achieving efficient separation of 0.045 mg of Lu³⁺ from 200 mg of Yb³⁺ with a Lu³⁺ purity of 90.9% and a yield of 98.4%. This study provides a feasible separation technique for the purification of NCA ¹⁷⁷Lu. Full article

Volatile compounds and aroma sensory profile of wines were researched in order to determine the effect of the coupage technique using monovarietal young white wines from La Mancha region. To conduct this study, the aroma compositions of Airén, Chardonnay, and Vermentino monovarietal wines and the wines obtained by blending monovarietal wines were extensively studied. Free aroma compounds were isolated by solid phase extraction (SPE) using dichloromethane and then analyzed by gas chromatography–mass spectrometry (GC-MS). Sensory aroma profile was determined using Quantitative Descriptive Sensory Analysis (QDA). Seventy-one (71) free aroma compounds were identified and quantified. C₆ and benzenic compounds were the principal groups of varietal aroma compounds in Airén and Chardonnay wines. The varietal aroma of monovarietal Vermentino wines is characterized by higher concentrations of terpene and C₁₃-norisoprenoids compounds. Wines obtained by the blending of monovarietal wines showed a higher concentration of principal aroma compounds of monovarietal wines and exhibited a higher sensory complexity than the monovarietal wines. The coupage technique intensified the principal sensory properties of Airén, Chardonnay, and Vermentino monovarietal wines and these were scored very positively by wine assessors, especially when the different grape variety contents of the blended monovarietal wines were split equally at 33% each, which provided wines with more aroma typicity than monovarietal wines. Full article

To address the challenge of developing the first squaramide-based ion pair receptor acting as an iniferter in the polymerization process, a well-known BDPA molecule with specific radical functions was incorporated into its structure. The developed ditopic receptor demonstrated the ability to cooperatively bind ion pairs. Moreover, it proved to be an effective iniferter in the polymerization reaction using methyl methacrylate. The polymerization process preserved the ion-binding properties of the receptor, enabling the formation of functional polymeric materials. It was shown that the resulting polymer with the embedded receptor can be used for salt extraction from both solid and liquid phases, whereas the reference receptor lacking the BDPA unit did not exhibit this capability. This opens new avenues for the design of intelligent and selective polymeric materials for applications in supramolecular chemistry and separation technologies. Full article

The consumption of pharmaceuticals during the COVID-19 pandemic increased significantly. As such, over-the-counter drugs such as acetaminophen (ACT), ibuprofen (IBU), metoprolol (MET), and propranolol (PRO) were among the pharmaceuticals that were widely used to contain COVID-19 symptoms. Therefore, this study investigated the occurrence of ACT, IBU, MET, and PRO in wastewater and river water systems, focusing on two provinces in South Africa (Gauteng (GP) and KwaZulu-Natal (KZN)). Generally, WWTP influents had the highest concentrations in both provinces. ACT, MET, and PRO were frequently detected compared to ibuprofen, particularly in KZN, during the second wave of the COVID-19 pandemic. However, a low detection occurred during the fourth wave of the COVID-19 pandemic. The concentrations of ACT, IBU, MET, and PRO in influent wastewater samples ranged from ND-480 µg/L, ND-54.1 µg/L, ND-52.8 µg/L, to ND-13.1 µg/L, respectively. In comparison with influent samples, ACT, IBU, MET, and PRO concentrations of effluent wastewater samples were generally at lower concentration levels: ACT (ND-289 µg/L), IBU (ND-36.1 µg/L), MET (ND-13.9 µg/L), and PRO (ND-5.53 µg/L). The removal efficiencies of the selected pharmaceuticals in KZN WWTPs ranged from 6.1 to 100% and −362.6 to 100% in the GP province. The ecological risk assessment results showed a low to high ecological risk against fish, Daphnia magna, and algae due to the presence of these pharmaceuticals. Full article

Phospholipids (PLs) are a group of biomolecules found in the milk fat globule membranes (MFGMs). Recently, MFGM phospholipids have attracted increasing amounts of attention due to their unique composition, stability, and potential health benefits, including protective effects against Alzheimer’s disease, hypercholesterolemia, and certain types of cancer. Although buffalo milk is the second most commonly produced milk and has high nutritional value, few studies have focused on the properties of buffalo MFGM. This study investigates the PLs composition of buffalo milk and related dairy by-products (whey and buttermilk). Milk and whey were collected from two dairy farms (A—small and B—big) to produce mozzarella buffalo cheese (high-pasteurization milk for GDO production and low for local); while buttermilk was obtained from a butter-making farm. Phospholipids were purified by a solid-phase extraction method and then identified by high-performance liquid chromatography with an evaporative light-scattering detector (HPLC/ELSD). Five classes of phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylserine (PS), and sphingomyelin (SM)] were identified. The thermal process of milk did not significantly affect the PLs milk. However, local whey showed a higher concentration of total PLs than GDO, which was mainly represented by PE followed by PC content. Farm A exhibited higher PL content than B, particularly with a greater concentration of SM. Buttermilk showed the lowest PLs content. These findings offer valuable insights for the dairy industry and related applications, contributing to the valorization of buffalo dairy products. Full article

Thermal stimulation represents an effective method for enhancing reservoir permeability, thereby improving geothermal energy recovery in Enhanced Geothermal Systems (EGS). The phase-field method (PFM) has been widely adopted for its proven capability in modeling the fracture behavior of brittle solids. Consequently, a coupled thermo-mechanical phase-field model (TM-PFM) was developed in COMSOL 6.2 Multiphysics to probe thermal fracturing mechanisms in reservoir rocks. The TM-PFM was validated against the analytical solutions for the temperature and stress fields under steady-state heat conduction in a thin-walled cylinder, three-point bending tests, and thermal shock tests. Subsequently, two distinct thermal fracturing modes in reservoir rock under high-temperature conditions were investigated: (i) fracture initiation driven by sharp temperature gradients during instantaneous thermal shocks, and (ii) crack propagation resulting from heterogeneous thermal expansion of constituent minerals. The proposed TM-PFM has been validated through systematic comparison between the simulation results and the corresponding experimental data, thereby demonstrating its capability to accurately simulate thermal fracturing. These findings provide mechanistic insights for optimizing geothermal energy extraction in EGS. Full article

This study aimed to develop a reliable method for profiling reducing sugars in honey using capillary zone electrophoresis with laser-induced fluorescence detection (CZE-LIF). Reducing sugars were derivatized with 8-aminopyrene-1,3,6-trisulfonic acid (APTS) in the presence of 2-picoline borane, a safer alternative to sodium cyanoborohydride. Key parameters influencing the derivatization efficiency—temperature, pH, incubation time, and reagent concentrations—were systematically optimized. The highest labeling efficiency for glucose, mannose, and maltose was achieved at 50 °C in 0.5 M citric acid with 0.1 M APTS, while fructose showed low reactivity due to its ketose structure. To reduce the background signal from excess reagents, three cleanup strategies were evaluated. Liquid–liquid extraction with ethyl acetate effectively removed unreacted APTS without significant analyte loss, whereas solid-phase extraction and microextraction caused substantial losses of hydrophilic sugars. The method showed good linearity (0.5–10 mM, R² > 0.994), precision (RSD 0.81–13.73%), and accuracy (recoveries 93.47–119.75%). Stability studies indicated that sugar standards should be stored at –20 °C. The method was successfully applied to the analysis of four nectar honeys—rapeseed, acacia, phacelia, and dandelion—revealing differences in glucose and fructose content related to botanical origin. The results confirm the suitability of CZE-LIF for sensitive and selective carbohydrate analyses in complex food matrices. Full article

Fumonisins, primarily produced by Fusarium spp. and Aspergillus section nigri, are common contaminants in maize, cereal grains, and other processed and derived products, representing a significant risk to food safety and public health. This study presents the development and optimisation of a high-performance liquid chromatography method with fluorescence detection (HPLC-FLD) for the quantification of fumonisin B1 (FB1) and B2 (FB2) in various food matrices. In contrast with conventional protocols employing potassium phosphate buffers as the mobile phase, the proposed method utilises formic acid, offering enhanced compatibility with liquid chromatography systems. An automated online precolumn derivatisation with o-phthaldialdehyde (OPA) was optimised through experimental design and response surface methodology, enabling baseline separation of FB1 and FB2 derivatives in less than 20 min. The method demonstrated high sensitivity, with limits of detection of 0.006 µg mL⁻¹ for FB1 and 0.012 µg mL⁻¹ for FB2, and excellent repeatability (intraday RSD values of 0.85% and 0.83%, respectively). Several solid-phase extraction (SPE) strategies were evaluated to enhance sample clean-up using a variety of food samples, including dried figs, raisins, dates, corn, cornmeal, wheat flour, and rice. FumoniStar Inmunoaffinity columns were the only clean-up method that provided optimal recoveries (70–120%) across all tested food matrices. However, the MultiSep™ 211 column yielded good recoveries for both fumonisins in dried figs and raisins. Additionally, the C18 cartridge achieved acceptable recoveries for both fumonisins in dried figs and wheat flour. Full article

Compared with vanadium extraction by sodium roasting followed by water leaching, the calcification roasting–sulfuric acid leaching method is considered a promising approach for the comprehensive utilization of vanadium titanomagnetite, as it avoids the introduction of alkali metals. However, during vanadium extraction by sulfuric acid heap leaching, the diffusion of leaching reagents and leaching products was hindered by the deposition of leaching solid products. To address this issue, this study systematically investigated the leaching kinetics and the mechanisms underlying the deposition of leaching solid products. The results indicated that vanadium leaching was governed by a combination of liquid film diffusion and internal diffusion through solid-phase products during days 0–2, and by internal diffusion alone from day 2 to day 9. The primary solid products formed during leaching were calcium sulfate and silica gel. Calcium sulfate precipitated and grew within the pore via two-dimensional nucleation, while silicates formed silica gel through dehydration. By optimizing the sulfuric acid leaching conditions—specifically, maintaining an H⁺ concentration of 2 mol/L, a leaching temperature of 40 °C, and a liquid-to-solid ratio of 5:1—the formation of calcium sulfate and silica gel was effectively suppressed. Under these conditions, the vanadium leaching efficiency reached 75.82%. Full article