Search Results (178)

The time interval between the collection of biological material and the performance of toxicological analyses is particularly important when the appropriate storage temperature cannot be maintained. This issue is especially relevant in the determination of ethanol concentration in specimens obtained from drivers suspected of intoxication or being under the influence of ethanol, as well as in samples collected during post-mortem examinations. The present study evaluated the effect of room-temperature storage on ethanol concentrations in post-mortem blood, urine, costal cartilage, and intervertebral disc cartilage collected from 57 cadavers. According to Polish law, blood ethanol concentrations > 0.2 mg/mL and >0.5 mg/mL were classified as “after alcohol use” and “intoxication”, respectively. Two subgroups were therefore distinguished from the study group: 27 ethanol-positive > 0.5 mg/mL (intoxicated) and 30 ethanol-negative cases—less than or equal to 0.5 mg/mL (sober). Ethanol concentrations were determined using gas chromatography with flame ionization detection (GC-FID). Statistically significant differences in blood ethanol concentration were observed in ethanol-positive individuals depending on storage time after sample collection (p < 0.001). Under the storage conditions used in this study, no increase in ethanol concentration was observed in samples collected from ethanol-negative individuals. In ethanol-positive individuals, ethanol concentrations decreased progressively in all analyzed matrices during room-temperature storage. Urine showed the greatest stability throughout the observation period. In both cartilage matrices, ethanol was detectable up to day 3, whereas all measurements were negative from day 4 onward. Blood ethanol concentrations also decreased during storage. By day 4, the mean concentration was below the legal intoxication threshold. Full article

Background/Objectives: In this study, nanoemulsions containing Thymus vulgaris (TV) and Rosmarinus officinalis (RO) essential oils (EOs) were prepared and characterized, and their antibacterial, antifungal, and antibiofilm activities were evaluated against some oral pathogens. Methods: Three nanoemulsions containing 5% TV-EO (F1), 5% RO-EO (F2), and a combination of 2.5% TV-EO and 2.5% RO-EO (F3) were prepared by emulsification followed by high-speed homogenization. Results: Gas chromatography–mass spectrometry coupled with flame ionization detection (GC-MS-FID) analysis revealed linalool (79.51%) as the major constituent of TV-EO and eucalyptol (58.13%), together with camphor (10.80%), as the predominant compounds of RO-EO. All nanoemulsions exhibited nanosized droplets, low polydispersity index (PDI) values (<0.3), and moderate to high colloidal stability. Transmission electron microscopy (TEM) analysis revealed predominantly spherical droplets in all formulations (F1–F3). All formulations exhibited antimicrobial activity against Streptococcus mutans, Lactobacillus acidophilus, Enterococcus faecalis, and Candida albicans. Among the tested formulations, F2 showed the strongest antibacterial activity, whereas F3 exhibited the highest antibiofilm activity against mature S. mutans biofilms, achieving approximately 80% inhibition, comparable to chlorhexidine (CHX). Although F3 possessed the smallest droplet size, its antimicrobial activity was lower than that of F2, suggesting that biological activity was influenced not only by droplet size but also by EO composition. Conclusions: These findings demonstrate the potential of TV-EO and RO-EO nanoemulsions as promising natural alternatives for mouthwash formulations and highlight the importance of EO composition in determining antimicrobial and antibiofilm efficacy. Full article

Closed-cell phenolic foam (PF) insulation is widely assumed to exhibit monotonically increasing thermal conductivity after cutting, driven by progressive blowing agent release. This study reports a previously uncharacterized behavior: a consistent decrease–minimum–rebound pattern in the days to weeks after cutting, defined here as the transient thermal conductivity minimum (TTCM). Using n-pentane-blown PF foam, thermal conductivity and mass were tracked under standard (23 °C) and accelerated aging conditions (70 °C, 110 °C; slicing per KS M ISO 11561), complemented by gas chromatography–flame ionization detection (GC-FID), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FT-IR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), and scanning electron microscopy (SEM). TTCM reductions of 3.8–16.7% were observed across all closed-cell specimens; a reference PF foam with cell-wall micro-perforations showed no TTCM, establishing intact closed-cell structure as a prerequisite. The mechanism is attributed to redistribution of dissolved n-pentane from the polymer matrix into the cell gas phase, thermodynamically favored by the proximity of n-pentane’s boiling point (36.07 °C) to the heat flow meter (HFM) hot plate temperature (33 °C). In the post-TTCM phase, thermal conductivity rises progressively as n-pentane is displaced by air; the rate of this rise is strongly dependent on diffusion path length. These results establish two mechanistically distinct aging stages and identify their respective governing factors. Full article

This study developed an analytical method based on comprehensive two-dimensional gas chromatography–mass spectrometry/flame ionization detection (GC×GC-MS/FID) for the simultaneous qualitative and quantitative analysis of phenolic compounds in coal-derived liquids. After sample injection, the analytes were first separated on a non-polar column in the first dimension and then transferred via a modulator to a medium-polar column for further orthogonal separation. The target phenolic compounds were simultaneously identified by MS and quantified by FID. By comparing the quantitative performance of the area normalization, external standard, and internal standard methods, the internal standard method was found to be more accurate and reliable. The limits of detection (LODs) for individual phenolic compounds ranged from 0.011 to 0.263 mg/L. Acceptable recoveries were obtained in spiked recovery tests using real coal tar samples, and the relative standard deviations (RSDs, n = 6) for repeatability tests met the acceptance criteria for quantitative analysis. These results demonstrate that the proposed GC×GC-MS/FID strategy enables efficient separation and reliable quantification of phenolic compounds, providing a valuable reference for the compositional analysis of complex mixtures in coal tar. Full article

Background: Premium table grapes are often underutilized for winemaking due to suboptimal sugar–acid balance and limited aroma complexity. This study evaluated the chemical and sensory characteristics of wine produced through mixed fermentation of yeasts and lactic acid bacteria (LAB) to valorize Kyoho grapes. Methods: Kyoho grapes were fermented using a sequential yeast inoculation (Hanseniaspora opuntiae followed by Saccharomyces cerevisiae, HO+SC), combined with either simultaneous (SIM-MLF) or sequential (SEQ-MLF) malolactic fermentation using Lactoplantibacillus plantarum. Volatile compounds were quantified via Gas Chromatography with Flame Ionization Detection (GC-FID), and consumer sensory evaluation was conducted. Results: The HO +SC fermentation increased total ester content 4.21-fold compared to the S. cerevisiae control (p < 0.05). SIM-MLF yielded significantly higher levels of ethyl lactate, diethyl succinate, and diacetyl than SEQ-MLF (p < 0.05), with total esters reaching 267.38 ± 17.71 mg/L. Both MLF treatments reduced titratable acidity and increased pH. Conclusions: Sensory evaluation confirmed that SIM-MLF achieved the highest overall acceptance (7.63/9), strongly associated with “floral,” “blackberry,” and “creamy” descriptors. Thus, SIM-MLF effectively enhances the sensory attributes of Kyoho wine, providing a practical valorization strategy for non-traditional grape varieties. Full article

The photocatalytic conversion of carbon dioxide (CO₂) into methanol represents a promising strategy for both greenhouse gas mitigation and renewable fuel production. In this study, a niobium-based metal–organic gel (Nb-MOG) was employed as a photocatalyst for the reduction of CO₂ to methanol under UV irradiation in a batch photoreactor. A two-factor experimental design was conducted to evaluate the effects of sodium carbonate concentration and catalyst loading on methanol production. The Nb-MOG catalyst was dispersed in the reaction medium and irradiated with UV light for four hours. During the photocatalytic experiments, samples were periodically collected and analyzed by headspace gas chromatography coupled with flame ionization detection (HS-GC-FID) to quantify methanol production. The results showed that both the Na₂CO₃ concentration and catalyst loading exerted significant positive effects on methanol formation. The highest methanol yield was achieved at a Na₂CO₃ concentration of 0.10 mol·L⁻¹ and a catalyst loading of 0.50 g·L⁻¹. The experimental design results demonstrated a good fit of the statistical model to the experimental data, highlighting its predictive capability and confirming the reliability of the obtained results. Furthermore, Nb-MOG exhibited enhanced light-harvesting and charge-transfer properties, leading to measurable methanol production under the investigated conditions. These findings contribute to a better understanding of Nb-MOG’s photocatalytic behavior and demonstrate its potential for application in a sustainable CO₂ reduction system. Full article

Background/Objectives: Lavandula cariensis species is cultivated uncommonly in the western region of Turkey. The colloquial appellations avayianos, karabasi, and myra are used to refer to the L. cariensis plant. The essential oil of L. cariensis was studied for its potential antiglaucoma, antioxidant, antidiabetic, and acetylcholinesterase inhibitory effects. Methods: The inhibitory effect of the essential oil of L. cariensis on the acetylcholinesterase (AChE), carbonic anhydrase II (CA II), and α-amylase enzymes was determined. Therefore, chemical profiles of L. cariensis’ essential oil were identified using Gas Chromatography Mass Spectrometry (GC-MS) and as Chromatography with Flame Ionization Detection (GC-FID) analyses. Results: Camphor (39.73%), fenchone (19.49%), exobornyl acetate (6.81%), camphene (5.49%), and eucalyptol (5.49%) were the most abundant compounds in L. cariensis essential oil. Radical scavenging effect of the essential oil of L. cariensis was examined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC₅₀: 231.0 ± 0.094 μg/mL) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) (IC₅₀: 7.45 ± 0.013 μg/mL) radicals. Also, the ferric ions (Fe³⁺), cupric ions (Cu²⁺), and Fe³⁺-2,4,6-tri(2-pyridyl)-S-triazine (TPTZ) complex reducing capabilities were studied. Additionally, essential oil of L. cariensis indicated a comparable level of inhibition towards hCA II (IC₅₀: 276.42 μg/mL), AChE (IC₅₀: 14.22 μg/mL), and α-amylase (IC₅₀: 475.63 μg/mL) enzymes. Conclusions: The evaluation of the antioxidant capabilities and enzyme inhibition profiling of the essential oil of L. cariensis will be made possible by this comprehensive study, which serves as a springboard for further research. The essential oil of L. cariensis demonstrated enzyme-inhibitory activities against target enzymes associated with Alzheimer’s disease, diabetes, and glaucoma. Also, this study’s in vitro inhibition suggests promising prospects. Full article

Diallyl disulfide (DADS) and diallyl trisulfide (DATS) are major allicin-derived organosulfur compounds associated with biological activity and sensitivity to processing conditions. This study aimed to quantify DADS and DATS in commercial garlic products using gas chromatography–flame ionization detection (GC-FID) and to evaluate the effects of product formulation and processing on their concentrations. Fresh garlic, marinated garlic, garlic oil, tinctures, powders, dragees, and oil- and granulate-based capsules were analyzed. The GC-FID method showed excellent linearity for both analytes (R² = 0.9999). Marked differences were observed among the investigated product types, and selected pairwise comparisons indicated statistically significant differences (p < 0.05). Garlic oil contained the highest concentrations of both compounds, with mean DADS and DATS levels of 179.98 and 102.26 mg/g, respectively. In contrast, the mean concentrations in all other product groups were substantially lower, reaching 0.01068 mg/g for DADS and 0.03649 mg/g for DATS. Oil-based formulations showed markedly higher DADS concentrations than powder- and granulate-based products, whereas DATS was relatively more dominant in powder-based formulations. Marination and thermal processing were associated with reduced diallyl sulfide levels. These findings demonstrate that the investigated commercial garlic products differed substantially in their DADS and DATS content, mainly depending on formulation and processing. The pronounced variability observed among the investigated commercial products highlights the need for improved analytical standardization and quality control of garlic-based products. Full article

Background: Sambucus ebulus L. berries contain numerous bioactive compounds, but their volatile molecular composition has not yet been fully characterized. In this study, we analyzed the volatile components of the essential oil and aqueous infusion prepared from dried S. ebulus fruits, followed by multitarget in silico analysis of the major compounds against the following enzymes implicated in neuroinflammation and oxidative stress, namely cyclooxygenase-2 (COX2), monoamine oxidases (MAO-A and MAO-B), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), for which inhibitory activity of plant-derived compounds has previously been reported. Methods: Steam distillation, gas chromatography-mass spectrometry (GC-MS), and gas chromatography-flame ionization detection (GC-FID) were employed for compound isolation and analysis. Molecular docking studies were performed using Schrödinger software (version 2025-1). Results: Fatty acid esters and hexahydrofarnesyl acetone predominated in the essential oil, whereas linalool was identified as the major constituent of the infusion. MAO-A was predicted to be the most favorable interaction target for hexahydrofarnesyl acetone and other major constituents. Conclusions: Our findings expand the currently limited available data on the volatile composition of S. ebulus fruits and characterize the volatile profile of its fruit infusion for the first time. The in silico analyses suggest that S. ebulus volatile constituents may interact with several target enzymes implicated in neurodegeneration and inflammation. Full article

The suckling phase is the critical window for rumen functional maturation, yet amino-acid-based interventions tailored to this stage remain scarce. L-citrulline (L-cit) bypasses hepatic first-pass metabolism, is converted to L-arginine peripherally, and resists ruminal microbial degradation, making it a candidate functional additive for early-life ruminants. This study evaluated whether dietary L-cit at 2 g·lamb⁻¹·d⁻¹ would improve rumen development and metabolic function in suckling Hu lambs. Twenty male Hu lambs were randomly assigned to a control (CON) or L-cit group (n = 10/group) and reared for 45 d (3 d adaptation + 42 d treatment). Growth and starter intake were assessed in all lambs; six lambs per group (n = 6) were subsequently slaughtered for rumen morphometry, gas chromatography–flame ionization detection (GC-FID) volatile fatty acid (VFA) quantification, 16S rRNA gene sequencing, and liquid chromatography–mass spectrometry (LC-MS) untargeted metabolomics. L-cit increased average daily starter intake by 25.96% (p = 0.036) and produced a 20.00% numerical but non-significant increase in average daily gain (ADG) (p = 0.203; Cohen’s d = 0.58). Rumen weight, volume, and papillary length, width, density, and epithelial thickness were all elevated (p < 0.05), whereas muscular thickness was unaffected (p = 0.162). Total VFA, acetate, propionate (+37.64%, p < 0.001), and butyrate were higher in the L-cit group; the molar proportion of propionate rose from 21.41% to 24.75%, and the acetate-to-propionate ratio declined from 2.90 to 2.44 (p = 0.005). Microbial richness (Chao1, Observed species) increased without altered evenness, and linear discriminant analysis effect size (LEfSe) identified L-cit-driven enrichment of propionate-generating and fiber-degrading genera, including Prevotellaceae_UCG-004, Ruminobacter, and the NK4A214_group. Of 539 differential metabolites (147 of which were annotated to the Kyoto Encyclopedia of Genes and Genomes (KEGG) database), KEGG enrichment highlighted linoleic acid metabolism and purine metabolism as the biologically interpretable targets. Microbiota–metabolite correlations linked L-cit-enriched genera to up-regulated metabolites such as adenine. Dietary L-cit at 2 g·lamb⁻¹·d⁻¹ enhances starter intake, promotes rumen epithelial development, promotes a shift toward enhanced propiogenic fermentation within an acetate-dominant profile, and remodels the microbiota–metabolome axis, supporting its application as a functional additive during the suckling phase of ruminants. Because epithelial barrier integrity, oxidative stress, and inflammatory markers were not directly measured, these findings should be interpreted as morphological and association-based evidence, and further functional validation is required. Full article

The use of natural products as alternatives to synthetic fungicides has gained increasing importance in crop protection. Among these, clove (Syzygium aromaticum) and its active compound, eugenol, are well known for their antifungal properties. However, it remains unclear whether the antifungal activity of clove is primarily driven by its major constituent, eugenol, or whether the whole essential oil exhibits greater or synergistic efficacy. Addressing this question is crucial for optimizing their application as biofungicidal agents; The chemical composition of clove essential oil was characterized using gas chromatography–flame ionization detection (GC-FID) and gas chromatography–mass spectrometry(GC-MS). The antifungal activity of the essential oil and pure eugenol (300 µg/mL) was evaluated in vitro against Botryotinia fuckeliana, Rhizoctonia solani, and Verticillium dahliae on potato dextrose agar (PDA). Mycelial growth inhibition was quantified, and data were analyzed using two-way analysis of variance (ANOVA) followed by Tukey’s honestly significant difference (HSD) test (α = 0.05); Eugenol exhibited higher antifungal activity than the essential oil across all tested species. V. dahliae was completely inhibited (100%) by eugenol, while the essential oil showed lower efficacy. Despite the high eugenol content (87.3%) in the oil, its reduced activity suggests that minor constituents may modulate overall antifungal performance. These findings demonstrate that eugenol is more effective than clove essential oil as an antifungal agent. This highlights that the biological activity of clove is largely driven by its major active component, providing key insights for the development of more efficient biofungicidal strategies. Full article

Contamination of soils by petroleum hydrocarbons is a long-standing environmental and public-health issue in oil-producing areas. This study compared natural attenuation and biostimulation using date palm waste for the remediation of crude-oil-contaminated soil collected near the North Oil Company facilities in Kirkuk, Iraq (0–10 cm). The experiment was conducted as an outdoor semi-field, pot study under a rain shelter over 160 days, using 2 kg of soil per pot; palm waste (<5 mm) was added at 500 g per pot in the biostimulation treatment. This study provides preliminary semi-field evidence from Iraq using locally available date palm waste under semi-arid outdoor conditions. Gas chromatography with flame ionization detection (GC–FID) was used to measure total petroleum hydrocarbons (TPH; C8–C40), while gas chromatography–mass spectrometry (GC–MS) was used to measure 18 priority polycyclic aromatic hydrocarbons (PAHs), grouped into 2–3- and 4–6-ring categories; the microbial number was measured as colony-forming units (CFU). Biostimulation reduced TPH from 38,751 mg kg⁻¹ at day 0 to 9205 mg kg⁻¹ by day 40 (76.2% reduction), which was later sustained to 4717 mg kg⁻¹ by day 160 (87.8% reduction). Natural attenuation showed relatively slower and smaller reductions over the same period. Full article

Ambrosia arborescens Mill., a native medicinal plant traditionally used in the Andean region, has a poorly characterized essential oil (EO), with no prior reports on its anticholinesterase or antioxidant potential. As a first report and preliminary screening study, this work characterizes the chemical composition of the EO and evaluates its acetylcholinesterase (AChE) inhibitory and antioxidant activities. The EO was isolated by hydrodistillation and analyzed using gas chromatography coupled with mass spectrometry (GC–MS) and flame ionization detection (GC-FID). The biological activities were evaluated using the Ellman method to determine AChE inhibition and using ABTS and DPPH assays to determine antioxidant activity. Analysis of the chemical composition revealed 31 compounds, and the major components were γ-curcumene (28.63%), trans-muurola-4(14),5-diene (27.85%), and eucavone (18.46%). The EO showed moderate AChE inhibitory activity, with an IC₅₀ value of 28.04 ± 1.02 µg/mL, and limited antioxidant activity, with ABTS SC₅₀ = 373.75 ± 1.30 µg/mL and DPPH SC₅₀ = 1101.84 ± 1.63 µg/mL. These findings demonstrate that the EO possesses selective anticholinesterase activity and limited antioxidant capacity. Given the structural diversity of its constituents, the observed bioactivity is likely the result of the combined contributions of multiple components; however, the specific active constituents and potential synergistic interactions require further investigation through bioassay-guided fractionation. These findings represent the first preliminary screening of the biological activities of A. arborescens EO and provide a foundation for future bioactivity-guided investigations. Full article

Aim: The aim of this study was to develop and validate a reliable HS-GC-FID/FID method for the determination of ethanol and other low-molecular-weight volatile compounds in biological fluids for forensic applications. Method: The method is based on headspace gas chromatography with dual-column and dual flame ionization detection (HS-GC-FID/FID), using Zebron ZB-BAC1 and ZB-BAC2 columns. The procedure was validated in terms of linearity, limits of detection and quantification, precision, and accuracy, as well as carryover. Results: The method demonstrated linearity over the concentration range of 0.05–5.0‰, with R² values of 0.997–0.999. The limit of quantification (LOQ) was 0.05‰, and the limit of detection (LOD) was 0.025‰. Precision and accuracy were both below 5%. Retention times (min) on the two columns were as follows: methanol (1.70/1.81), ethanol (2.06/2.29), acetone (2.60/2.59), isopropanol (2.45/2.73), n-propanol (3.24/3.98), and n-butanol (6.35/8.45). The developed method was successfully evaluated through international proficiency testing and is routinely applied in our laboratory for forensic casework. Conclusions: The developed HS-GC-FID/FID method provides accurate and reliable determination of ethanol and other relevant volatile compounds in biological fluids (i.a., blood) and meets the requirements for forensic toxicology. Additionally, the literature review conducted in this study highlights that globally unified principles for forensic alcohol analysis are still lacking, and that certain inappropriate methodological approaches remain in use. The present paper also provides recommendations defining essential methodological requirements to ensure the evidential reliability of ethanol analysis in forensic toxicology. Full article

Caraway essential oil (CEO) and chitosan-based nanoparticles incorporating CEO (CNPs CEO) were evaluated as natural preservatives for fresh pork sausages stored at +4 °C for five days. The chemical composition of CEO was characterized by gas chromatography–mass spectrometry (GC/MS) and gas chromatography with flame ionization detection (GC/FID); carvone (92.5%) and limonene (5.8%) were identified as dominant components. Eight experimental treatments were applied: control, CEO at 0.2, 0.4, and 0.6 mg/g, chitosan nanoparticles (CNPs), and CNPs CEO at 0.2, 0.4, and 0.6 mg/g. Encapsulation efficiency of CEO in chitosan nanoparticles was 67.7 ± 1.91%. Microbiological quality (total bacterial count (TBC), lactic acid bacteria, yeasts and moulds), lipid oxidation (TBARS), pH, and sensory attributes of raw and thermally processed sausages were monitored throughout storage. CEO reduced microbial growth and lipid oxidation in a concentration-dependent manner, while CNPs CEO formulations showed markedly superior performance. The CNPs CEO 0.6 mg/g treatment achieved the greatest inhibitory effect on all microbiological parameters, reducing TBC for 1.6 log CFU/g and limiting lipid oxidation, yielding final malondialdehyde values of 1.15 mg MDA/kg, approximately 50% lower than the control (2.18 mg MDA/kg). Sensory evaluation indicated that CNPs CEO-treated sausages maintained acceptable colour, odour, juiciness, texture, and overall acceptability throughout the storage period. The sample treated with CNPs CEO 0.6 mg/g remained above the acceptability level for all analyzed parameters for 5 days of storage, while the control became unacceptable for lipid oxidation on the fifth day and sensory unacceptable after the third day. These findings demonstrate that the application of CNPs CEO in sausage production enhances their stability, shelf life, and sensory characteristics, indicating a promising no-additive strategy in the industrial production of fresh pork sausages. Full article