Search Results (102)

Chlorinated paraffins (CPs) are a class of persistent organic pollutants that pose potential human health risks through dietary exposure. In this study, we analyzed CPs in 55 chicken egg samples collected from five regions across China. Short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) were detected using a two-dimensional gas chromatograph coupled with an electron-capture negative-ionization mass spectrometer. Dietary exposure risks were assessed using the margin of exposure (MOE) approach based on the food consumption data of Chinese residents from 2018 to 2020. The average concentrations of SCCPs and MCCPs in all samples were 28.4 ng/g wet weight (ww) and 176.5 ng/g ww, respectively. The congener profiles of SCCPs and MCCPs were similar across different regions, with C_10–11 Cl_6–7 as the dominant homologs. For MCCPs, the average contributions of C₁₄-CP, C₁₅-CP, C₁₆-CP, and C₁₇-CP were 25%, 21%, 27%, and 27%, respectively. The estimated daily intake (EDI) for the entire population was 18.3 ng/kg body weight (bw)/d for SCCPs and 118.3 ng/kg bw/d for MCCPs. In the consumer-only group, the average exposure levels of SCCPs and MCCPs were 27.8 ng/kg bw/d and 174.1 ng/kg bw/d, respectively. This preliminary risk assessment indicates that there is no health risk to the Chinese population from exposure to CP through consumption of chicken eggs. Full article

Achieving sustainable air quality improvements in rapidly industrializing regions requires a clear understanding of the emission sources that drive the formation of PM_2.5 pollution. This study identified the sources of PM_2.5 and its organic carbon (OC) in Zibo, a typical industrial city in Northern China Plain, using the Positive Matrix Factorization (PMF) model during five pollution episodes (P1–P5) from 26 November 2022 to 9 February 2023. A high-temporal-resolution online observation of 61 organic molecular tracers was conducted using an Aerodyne TAG stand-alone system combined with a gas chromatograph–mass spectrometer (TAG-GC/MS) system. The results indicate that during pollution episodes, PM_2.5 was contributed by 32.4% from coal combustion and 27.1% from inorganic secondary sources. Moreover, fireworks contributed 13.1% of PM_2.5, primarily due to the extensive fireworks during the Gregorian and Lunar New Year celebrations. Similarly, coal combustion was the largest contributor to OC, followed by mobile sources and secondary organic aerosol (SOA) sources, accounting for 16.2% and 15.3%, respectively. Although fireworks contributed significantly to PM_2.5 concentrations (31.6% in P4 of 20–24 January 2023), their impact on OC was negligible. Overall, a combination of local and regional industrial combustion emissions, mobile sources, extensive residential heating during cold weather, and unfavorable meteorological conditions led to elevated secondary aerosol concentrations and the occurrence of this haze episode. The high-temporal-resolution measurements obtained using the TAG-GC/MS system, which provided more information on source-indicating organic molecules (tracers), significantly enhanced the source apportionment capability of PM_2.5 and OC. The findings provide science-based evidence for designing more sustainable emission control strategies, highlighting that the coordinated management of coal combustion, mobile emissions, and wintertime heating is essential for long-term air quality and public health benefits. Full article

Phthalic acid esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) are known to potentially impact both marine organisms and human health through the consumption of fish and seafood. In this study, the concentrations of 12 priority PAHs and 6 PAEs were analyzed in the tissues of 76 samples of five farmed fish species, including Litopenaeus vannamei (crustacean), Babylonia areolata, Marcia hiantina (mollusk), Trachinotus blochii, and Epinephelus lanceolatus (fish), collected from four coastal sites in Khanh Hoa province. Freeze-dried tissue was extracted using water bath ultrasonication with an acetone/n-hexane mixture. A triple quadrupole gas chromatograph–mass spectrometer (GC-MS/MS) was used for the analyses. The results showed that the total PAHs had low contamination levels. Among the PAEs, bis(2-ethylhexyl) phthalate (DEHP) exhibited the highest concentrations. The calculated hazard index (HI) for PAEs suggested no significant health risk. Six PAHs were detected, ranging from 9.14 µg kg⁻¹ in Pacific white shrimp to 47.34 µg kg⁻¹ in cockle. The incremental lifetime cancer risk (ILCR) values for PAHs in some samples exceeded the acceptable safety threshold. In the future, natural fish, environmental samples (seawater and marine sediment), and other information on natural conditions will be collected for analyses. This is the first report on the levels and health risks of PAEs and PAHs in farmed fishes along the Khanh Hoa coast. Full article

Currently, the potential environmental concerns around the world for polycyclic aromatic hydrocarbon carcinogenic (PAHCs) contamination as carcinogenic compounds in industrial soils (automobile industry) are rising day by day. At present, the technology of treating contaminated soils using photocatalysts is commonly used; however, this study tested photolysis and photocatalysis through ultraviolet light (306 nm) due to its high treatment efficiency. FeCl₃ (0.3, 0.4 M) was used as an iron catalyst for each treatment in the presence of H₂O₂ (10%, 20%) as an oxidizing agent. The impact of light treatment on soils that contained various concentrations of PAHCs like naphthalene (NAP), chrysene (CRY), benzo(a) pyrene (BaP), indeno (1,2,3-cd) pyrene (IND) was investigated. The QuEChERS method was used to extract PAHCs, and a gas chromatograph mass spectrometer (GCMSMS) was used to determine concentration. The concentrations of PAHCs were measured for soils at intervals of every 2 h after exposure to ultraviolet rays. The results showed a decrease in PAHCs concentrations with increased exposure to UV irradiation, as the initial values were 26.8 ng/g (NAP), 97 ng/g (CRY), 9.1 ng/g (BaP) and 9.7 ng/g (IND), which decreased to 2.17 ng/g (NAP), 3.14 ng/g (CRY), 0.33 ng/g (BaP) and 0.46 ng/g (IND) at 20, 40, 30 and 40 h of UV exposure; moreover, with an increase in concentration of the catalyst (0.4 M FeCl₃ with 20% H₂O₂), NAP, CRY, BaP and IND became undetectable at 8, 26, 14 and 20 h, respectively. It was concluded that a significant effect of ultraviolet rays on the photolysis of PAHCs, along with Photovoltaic at 306 nm wavelength, was observed while using FeCl₃ (0.4 M) combined with H₂O₂ (20%) produced better results in a shorter time compared to FeCl₃ (0.3 M) with H₂O₂ (10%). Full article

Investigating atmospheric volatile organic compounds (VOCs) is critical for understanding their sources, chemical reactivity, and impacts on air quality, climate, and human health, especially in remote regions like the Tibetan Plateau where baseline data remains scarce. In this study, ambient VOCs species were simultaneously measured at four remote background sites on the Tibetan Plateau (Nyingchi, Namtso, Ngari, and Mount Everest) from 2012 to 2014 to investigate their concentration, composition, sources, and chemical reactivity. Weekly integrated samples were collected and analyzed using a Gas Chromatograph-Mass Spectrometer/Flame Ionization Detector (GC-MS/FID) system. The total VOC mixing ratios exhibited site-dependent variability, with the highest levels observed in Nyingchi, followed by Mount Everest, Ngari and Namtso. The VOC composition in those remote sites was dominated by alkanes (25.7–48.5%) and aromatics (11.4–34.7%), followed by halocarbons (19.1–28.1%) and alkenes (11.5–18.5%). A distinct seasonal trend was observed, with higher VOC concentrations in summer and lower levels in spring and autumn. Source analysis based on correlations between specific VOC species suggests that combustion emissions (e.g., biomass burning or residential heating) were a major contributor during winter and spring, while traffic-related emissions influenced summer VOC levels. In addition, long-range transport of pollutants from South Asia also significantly impacted VOC concentrations across the plateau. Furthermore, reactivity assessments indicated that alkenes were the dominant contributors to OH radical loss rates, whereas aromatics were the largest drivers of ozone formation potential (OFP). These findings highlight the complex interplay of local emissions and regional transport in shaping VOC chemistry in this high-altitude background environment, with implications for atmospheric oxidation capacity and secondary pollutant formation. Full article

Amino acids (AAs), a type of nitrogen-based organic compounds in the atmosphere, are directly and indirectly related to climate change, and as their link to allergic diseases becomes more known, the need for quantitative analysis of ultrafine dust (PM_2.5) will become increasingly necessary. When sensing water-soluble AAs using a gas chromatograph combined with a tandem mass spectrometer (GC-MS/MS), derivatization should be considered to increase the volatility and sensitivity of target analytes. In this study, two methods were used to compare and evaluate 13 AA derivatives in PM_2.5 samples: N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide with 1% tert-butyldimethylchlorosilane (MTBSTFA w/1% t-BDMCS), which is preferred for silylation, and ethyl chloroformate (ECF) with methanol (MeOH) for chloroformate derivatization. The most appropriate reaction conditions for these two derivative methods, such as temperature and time, and the analytical conditions of GC-MS/MS for the qualitative and quantitative analysis of AAs were optimized. Furthermore, the calibration curve, detection limit, and recovery of both methods for validating the quantification were determined. The two derivative methods were applied to 23 actual PM_2.5 samples to detect and quantify target AAs. The statistical significances between pairwise measurements of individual AAs detected by both methods were evaluated. This study will help in selecting and utilizing appropriate derivative methods for the quantification of individual AAs in PM_2.5 samples. Full article

Volatile organic compounds (VOCs) in urine headspace are potential biomarkers for different medical conditions, as canines can detect human diseases simply by smelling VOCs. Because dogs can detect disease-specific VOCs, gas chromatography–mass spectrometry (GC–MS) systems may be able to differentiate medical conditions with enhanced accuracy and precision, given they have unprecedented efficiency in separating, quantifying, and identifying VOCs in urine. Advancements in instrumentation have permitted the development of portable GC–MS systems that analyze VOCs at the point of care, but these are designed for environmental monitoring, emergency response, and manufacturing/processing. The purpose of this study is to repurpose the HAPSITE^® ER portable GC–MS for identifying urinary VOC biomarkers. Method development focused on optimizing sample preparation, off-column conditions, and instrumental parameters that may affect performance. Once standardized, the method was used to analyze a urine standard (n = 10) to characterize intra-day reproducibility. To characterize inter-day performance, n = 3 samples each from three volunteers (and the standard) were analyzed each day for a total of four days (n = 48 samples). Results showed the method could detect VOC signals with adequate reproducibility and distinguish VOC profiles from different volunteers with 100% accuracy. Full article

Artisanal kefir is produced by fermenting milk with kefir grains, resulting in a lightly carbonated drink with health-promoting bioactive compounds. However, sensory variability and fermentation conditions challenge its standardization, limiting commercialization in Brazil due to regulatory requirements. This study evaluated the physicochemical properties, volatile compounds, and microbiological stability of artisanal kefir produced in southern Brazil during 30 days of storage. Metabarcoding analysis, carried out by sequencing the V3/V4 regions of the 16S rRNA gene (bacteria) and the ITS region (fungi), revealed an increase in bacterial diversity, with a predominance of Enterococcus and Acetobacter, while fungal diversity decreased, with a predominance of Kazachstania. The physicochemical parameters remained stable. The concentration of volatile compounds, analyzed using a gas chromatograph coupled to a mass spectrometer, decreased, except for an increase in 2-heptanol. The aromatic profile was enriched with alcohols and ketones, possibly influenced by Enterococcus and Acetobacter. These findings show that kefir maintained microbiological stability and adequate sensory characteristics throughout the period analyzed. The study provides subsidies for the standardization of artisanal kefir and compliance with Brazilian quality standards, as well as guiding future research into durability, quality, and consumer perception. Full article

Brominated flame retardants (BFRs), including tetrabromobisphenol A (TBBPA) and dibromoneopentyl glycol (DBNPG), are present in both saturated and unsaturated polyester resins (UPRs). Given their toxicity, it is imperative to assess the content of this group of chemicals to ensure product safety and environmental sustainability, considering the paucity in the literature of analytical methods to evaluate them, particularly in solid matrices as UPRs. This study aimed to develop a fully automated gas chromatographic analysis of these BFRs, utilizing a flame ionization detector (FID), with prior derivatization of TBBPA and DBNPG with acetic anhydride. A chemometric evaluation was conducted for the derivatization step to enhance the yield of the procedure. The optimized method met the desired requirements for specificity, accuracy, and sensitivity, showing limits of detection (LOD) and quantitation (LOQ), respectively, of 1.1 µg/mL and 3.3 µg/mL for DBNPG and 3.6 µg/mL and 10.8 µg/mL for TBBPA. Other conventional detectors, i.e., an Electron Capture Detector (ECD) and a Mass Spectrometer (MS), were tested. The ECD showed a higher sensitivity than the FID and MS; however, its linearity proved to be more limited, making it unsuitable for higher concentration scenarios. The MS detector yielded results comparable with those of the FID, yet the latter is a cheaper and more sensitive alternative. Full article

Citrus x limonia is an aromatic species belonging to the Rutaceae family. In the present study, the chemical composition, enantiomeric distribution, and biological activity of the essential oil isolated from leaves of Citrus x limonia were determined. The essential oil was extracted through hydrodistillation. The chemical composition of the essential oil was determined by gas chromatography (GC) coupled to a flame ionization detector (GC-FID), and a mass spectrometer detector (GC-MS) using a nonpolar column. The enantiomeric distribution was performed using two enantioselective chromatographic columns. Antimicrobial activity was determined using the broth microdilution method. The antimicrobial activity was tested against eight bacteria and two fungi. The antioxidant activity was determined through ABTS and DPPH methods. The spectrophotometric method was used to determine anticholinesterase activity. In the essential oil, forty-three compounds were identified. These compounds represent 99.13% of the total composition. Monoterpene hydrocarbons were the most representative group in number of compounds (fourteen) and in terms of relative abundance (65.67%). The main constituent is found to be limonene (25.37 ± 0.80%), β-pinene (23.29 ± 0.15%) and sabinene (8.35 ± 0.10%). Six pairs of enantiomers were identified in the essential oil from fruits of Citrus x limonia. The essential oil showed moderate antibacterial activity against Gram-positive cocci Enterococcus faecalis, and Gram-positive bacillus Lysteria monocytogenes with a MIC of 1000 μg/mL. The oil exhibited strong antifungal activity against fungi Aspergillus niger, and yeasts Candida albicans with a MIC of 250 and 500 μg/mL, respectively. The antioxidant activity of essential oil was weak in ABTS method with a SC₅₀ of 9.12 mg/mL. Additionally, the essential oil presented moderate anticholinesterase activity with an IC₅₀ of 71.02 ± 1.02 µg/mL. Full article

The course and kinetics of the reactions of sulfur mustard, nitrogen mustard and their selected analogues with sodium ethoxide were studied using a gas chromatograph coupled with a mass spectrometer. 2-chloroethyl ethyl sulfide (CEES), a monofunctional analogue of sulfur mustard (HD), bis(2-chloroethyl) ether (BCEE), an oxygen analogue of sulfur mustard, and bis(2-chloroethyl)amine, an analogue of nitrogen mustard HN-3, in which one hydrogen atom remains unsubstituted with a chloroethyl group, were used as imitators of mustards. For the study, the last mentioned compound was given the acronym HN-0. The research included checking how the form of sodium ethoxide influences the reaction rate. Two solutions were used: sodium ethoxide solution obtained by dissolving a commercially available compound in crystalline form and ethoxide solution obtained by dissolving sodium in ethanol. Additionally, the extent to which diethylenetriamine (DETA) accelerates the reactions of the studied compounds with sodium ethoxide was checked. The decontamination reactions were carried out in an anhydrous environment at a constant temperature of 25.0 °C. The rate of the mustard decontamination reaction increased significantly in systems containing DETA. Therefore, this amine can be used as a catalyst for this reaction. DETA has the most significant effect on the rate of the reaction of sodium ethoxide with CEES. The effect of the EtONa form was tested in the decontamination reaction of HD, revealing that both forms are equally effective, with only minor differences in reaction rates. Freshly synthesised sodium ethoxide reacts with HD 1.24 times faster. The study also assessed whether selected non-CWA compounds can be successfully used in studies as mustard imitators. Nitrogen mustard and bis(2-chloroethyl)amine reactions proceed according to the same mechanism—nucleophilic substitution. Bis(2-chloroethyl)amine reacts slightly faster than HN-3, both in solution with and without the addition of a catalyst. Sulfur mustard (HD) and CEES with sodium ethoxide and DETA undergo an elimination reaction, while BCEE undergoes a substitution reaction, which proceeds much slower. The observed differences disqualify BCEE as a sulfur mustard imitator. HD and CEES react with sodium ethoxide and DETA so quickly that the exact kinetic parameters under the developed experimental conditions could not be determined. Full article

The use of essential oils from certain herbal plants offers a promising alternative to synthetic insecticides for controlling the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Dryophthoridae), a major pest that causes significant damage to stored grains. Essential oils, particularly from aromatic herbs in the Apiaceae family, are widely used in medicinal, cosmetic, and food industries and provided insecticidal properties to mitigate the environmental and health hazards associated with synthetic insecticides. This research aimed to investigate the insecticidal and repellent effects of Apium graveolens L. (celery) seed essential oil against S. zeamais. Chemical analysis of the commercially produced essential oil from A. graveolens seeds was conducted using a gas chromatograph–mass spectrometer (GC-MS), and the biological activity of the essential oil was determined by ingestion, contact, fumigation, and repellent tests. The analysis identified D-limonene (64.21%) and α-humulene (17.46%) as primary components of the oil. Toxicity assays revealed an observable contact toxicity, with higher concentrations and prolonged exposure increasing its effectiveness. The contact toxicity assays reported an LC₅₀ of 19.83 nL/adult after 72 h. Additionally, the essential oil displayed repellent effects, effectively deterring weevils at concentrations above 16 µL/L air, but its feeding deterrence was weak. The essential oil’s strong insecticidal and repellent properties, which were concentration- and time-dependent, highlighted its potential as a sustainable alternative to synthetic pesticides for integrated pest management. Full article

The expansion of atmospheric observation networks for hydrofluorocarbons (HFCs), which are closely related to climate change and contribute to global warming, significantly impacts our society and daily life. Their emissions are estimated to increase in the future, which is a major challenge. Observations of HFCs globally were performed using expensive GHG–specific equipment installed at AGAGE and other sites, but many research institutions find it difficult to install such equipment. Therefore, we successfully developed a measurement method for six components of HFCs (HFC–23, HFC–32, HFC–125, HFC–134a, HFC–143a, and HFC–152a) with high atmospheric concentrations in various parts of the world by optimizing measurement parameters such as the sample transfer volume and rate, module cooling temperatures, the injection time, the GC oven temperature program, and the monitored ions of a commercially available preconcentrator–GC–MS. Because this developed measurement method is cost–effective and simpler to operate than those of GHG–specific equipment, it is expected to provide an opportunity for many research institutes to measure HFCs. Furthermore, in addition to HFCs, we confirmed that simultaneous measurements can be performed for 97 volatile organic compounds (VOCs), including hazardous components. This research can contribute to the observation of HFCs in countries and regions where the actual status of emissions is unclear or where no or few atmospheric observations were conducted. The results of those observations can be used to formulate more detailed global warming countermeasures. Full article

Mass spectrometry (MS) is the only instrumental analytical technology that utilizes unique properties of matter, that is, its mass (m) and electrical charge (z). In the magnetic and/or electric fields of mass spectrometers, electrically charged native or chemically modified (millions) endogenous and (thousands) exogenous substances, the analytes, are separated according to their characteristic mass-to-charge ratio (m/z) values. Mass spectrometers coupled to gas chromatographs (GC) or liquid chromatographs (LC), the so-called hyphenated techniques, i.e., GC-MS and LC-MS, respectively, enable reliable determination of the concentration of analytes in complex biological samples such as plasma, serum, and urine. A particular technology is represented by inductively coupled plasma-mass spectrometry (ICP-MS), which is mainly used for the analysis of metal ions. The highest analytical accuracy is reached by using mass spectrometers with high mass resolution (HR) or by tandem mass spectrometers, as it can be realized with quadrupole-type instruments, such as GC-MS/MS and LC-MS/MS, in combination with stable-isotope labeled analytes that serve as internal standards, like a standard weight in scales. GC-MS belongs to the oldest and most advanced instrumental analytical technology. From the very beginning, GC-MS found broad application in basic and applied research sciences. GC-MS has played important roles in discovering biochemical pathways, exploring underlying mechanisms of disease, and establishing new evidence-based pharmacological therapy. In this article, we make an inventory of the use of instrumental mass spectrometry in the life sciences and attempt to provide a perspective study on the future of analytical mass spectrometry in clinical science, mainly focusing on GC-MS and LC-MS. We used information freely available in the scientific database PubMed (retrieved in August–November 2024). Specific search terms such as GC-MS (103,000 articles), LC-MS (113,000 articles), and ICP-MS (14,000 articles) were used in the Title/Abstract in the “PubMed Advanced Search Builder” including filters such as search period (1970–2024). In total, around 103,000 articles on GC-MS, 113,000 articles on LC-MS (113,000), and 14,000 articles on ICP-MS were found. In the period 1995–2023, the yearly publication rate accounted for 3042 for GC-MS articles and 3908 for LC-MS articles (LC-MS/GC-MS ratio, 1.3:1). Our study reveals that GC-MS/MS, LC-MS/MS, and their high-resolution variants are indispensable instrumentations in clinical science including clinical pharmacology, internal and forensic medicine, and doping control. Long-tradition manufacturers of analytical instruments continue to provide increasingly customer-friendly GC-MS and LC-MS apparatus, enabling fulfillment of current requirements and needs in the life sciences. Quantitative GC-MS and GC-MS/MS methods are expected to be used worldwide hand in hand with LC-MS/MS, with ICP-MS closing the gap left for metal ions. The significance of analytical chemistry in clinical science in academia and industry is essential. Full article

This study deals with the separation and detection methods for 12 synthetic musk compounds (SMCs), which are some of the emerging contaminants in fish samples, are widely present in environmental media, and can be considered serious risks due to their harmful effects. For the separation of co-extracted substances and the target SMCs in fish samples after ultrasonic extraction, four solid-phase extraction (SPE) sorbents were investigated. The recoveries of SMCs from 10 mL of eluent, as optimized by the elution profile, were within the acceptable range of 80–120% in all SPE types, and it was found that nitro musk and polycyclic musk compounds were separated more clearly in Florisil SPE than others (Aminopropyl, Alumina-N, PSA). Furthermore, the results of measuring the matrix effects by each SPE through the spiking experiments showed that Florisil SPE was superior. The comparison of a gas chromatograph-single quadrupole mass spectrometer (GC-SQ/MS) with selected ion monitoring (SIM) mode and GC-triple quadrupole mass spectrometer (GC-QqQ-MS/MS) with multiple reaction monitoring (MRM) modes regarding the detection method of SMCs showed that the method detection limits (MDLs) of SMCs were on average ten times lower when GC-QqQ-MS/MS with MRM mode was used. The differences between the two methods can provide essential information for selecting an analytical method in related research fields that require appropriate detection levels, such as risk assessment or pollution control. Full article