Gas Chromatography-tandem Mass Spectrometry Research Articles

Development of a highly sensitive method based on QuEChERS and GC–MS/MS for the determination of polycyclic aromatic hydrocarbons in infant foods

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants that can be found in various food products, including those intended for infants. Due to their potential health risks, it is crucial to develop sensitive analytical methods for the accurate determination of PAHs in infant foods. This study describes the development and validation of a highly sensitive method for the quantification of European PAH markers, namely benzo[a]pyrene, benzo[a]anthracene, chrysene, and benzo[b]fluoranthene, using gas chromatography–tandem mass spectrometry (GC–MS/MS), in baby food samples. The first step was the optimization of the sample preparation procedure, performed using different methods based on the QuEChERS approach, also testing different extraction solvents. Several factors such as extraction efficiency, selectivity, and recovery were evaluated to choose the most effective procedure for sample preparation. Furthermore, the GC–MS/MS method was optimized, evaluating parameters such as linearity, sensitivity, accuracy, and robustness using spiked infant food samples. The method demonstrated excellent linearities with a correlation coefficient higher than 0.999 over a wide concentration range, and limits of detection and limits of quantification in the range 0.019–0.036 μg/kg and 0.06–0.11 μg/kg, respectively. Extraction recoveries were between 73.1 and 110.7%, with relative standard deviations always lower than 8%. These findings are compliant with the indications of the European Commission (Reg. 836/2011). To assess the applicability of the method to official control activities, a survey was conducted on commercially available infant food products. Four markers were determined in commercial samples belonging to different food categories for infants and young children. The outcome of this monitoring showed that PAH contamination, in all samples, was below the quantification limits. In conclusion, the developed GC–MS/MS method provides a highly sensitive and reliable approach for the determination of PAHs in baby foods. The optimized sample preparation, instrumental parameters, and validation results ensure accurate quantification of 4 PAHs even at trace levels. This method could contribute to the assessment of PAH exposure in infants and it could support regulatory efforts to ensure the safety and quality of infant food products with regular monitoring.

Gas chromatography-stable isotope ratio mass spectrometry prior solid phase microextraction and gas chromatography-tandem mass spectrometry: development and optimization of analytical methods to analyse garlic (Allium sativum L.) volatile fraction

Garlic (Allium sativum L.) is not only appreciated for its flavour and taste, but it is also recognized for various health properties. The European Commission, through the attribution of the Protected Designation of Origin (PDO) certification mark, has officially recognized some specific varieties of garlic. To protect not only the commercial value but also the reputation of this appreciated product, effective tools are therefore required. For the first time, a new compound specific isotope analysis method based on carbon stable isotopic ratio measurement of the three major volatile garlic compounds allyl alcohol (AA), diallyl disulphide (DD) and diallyl trisulphide (DT) through head-space solid phase microextraction (HS-SPME) followed by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) was developed. A within-day standard deviation (Srwithin-day) of 0.3‰, 0.4‰ and 0.2‰ for δ(13C) and a between-day standard deviation (Srbetween-day) of 0.8‰, 1.0‰ and 0.6‰ of AA, DT and DD was estimated. For the first time, the ranges of isotopic variability for the three volatile compounds of red garlic from two neighbouring Italian regions (Abruzzo and Lazio) were defined analysing 30 samples. The same dataset was also considered in analysing the percentage composition of the previously mentioned three volatile compounds through gas chromatography-tandem mass spectrometry (GC-MS/MS). The two analytical approaches were combined in this explorative study, aiming to provide potential parameters to discriminate garlic samples based on their geographical origin.

Determine the pharmacokinetics (half-life, volume of distribution and clearance) of AMB-FUBINACA in rats plasma using GC–MS / MS

BackgroundSeveral novel synthetic cannabinoids, including methyl 2-(1-(4-fluorobenzyl)-1Hindazole-3-carboxamido)-3-methylbutanoate (AMB-FUBINACA), have recently surfaced on the illicit drug market. To determine the pharmacokinetic properties (half-life, volume of distribution, and clearance) of AMB-FUBINACA in rats plasma, a straightforward, quick, and highly sensitive analytical approach was developed. MethodsEighteen Wistar rats were divided into two groups: one control (saline vehicle) and one treatment group (AMB-FUBINACA at 50 mg/kg). Blood samples (400 μL) were withdrawn via catheters immediately before (t = 0) and at 30, 60, 90, 120, and 240 min following injection. Samples were collected into 1 mL tuberculin syringes, then transferred to 1.5 mL plastic tubes containing 5 μl of 1000 IU/mL K3-EDTA (Thomas Scientific). Place the EDTA tubes containing samples in a centrifuge and spin at 1000 g for 10 min at 4 °C. The top layer is the plasma fraction, which is decanted into cryovials and stored at −20 °C until analysis. The gas chromatography tandem mass spectrometry (GC–MS/MS) method was optimized and validated, combined with liquid-liquid extraction, to analyze AMB-FUBINACA in rat plasma. ResultsThe research method successfully met the validation requirements set by the FDA, demonstrating selectivity and linear calibration curves within a concentration range of 0.5–1000 ng/ml. The correlation coefficient (r2) was determined to be 0.99, indicating a strong linear relationship. The analyte's limit of quantitation (LOQ) was determined to be 1–5 ng/mL. Subsequently, the method was successfully applied to investigate the pharmacokinetics of AMB-FUBINACA in rats' blood samples. Following oral administration, AMB-FUBINACA was rapidly absorbed, with a plasma half-life (t1/2) of 5.91 h, a volume of distribution (Vd) of 203.13 l, and a plasma clearance of 23.81122 L/h. ConclusionThese findings contribute to the understanding of AMB-FUBINACA's pharmacokinetics and pharmacodynamics.

Search for new green natural solid phases for sample preparation for PAHs determination in seafood samples followed by LC and GC–MS/MS analysis

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic organic pollutants found in various environments, notably aquatic ecosystems and the food chain, posing significant health risks. Traditional methods for detecting PAHs in food involve complex processes and considerable reagent usage, raising environmental concerns. This study explores eco-friendly approaches suing solid phases derived from natural sources in matrix solid phase dispersion. We aimed to develop, optimize, and validate a sample preparation technique for seafood, employing natural materials for PAH analysis. Ten natural phases were compared with a commercial reference phase. The methodology involved matrix solid phase dispersion and pressurized liquid extraction, followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Three solid phases (perlite, sweet manioc starch, and barley) showed superior performance in LC-MS/MS and were further evaluated with gas chromatography-tandem mass spectrometry (GC–Ms/MS), confirming perlite as the most effective phase. Validation followed Brazilian regulatory guidelines and European Community Regulation 2021/808/EC. The resulting method offered advantages in cost-effectiveness, reduced environmental impact, cleaner extracts, and enhanced analytical performance compared to the reference solid phase and LC-MS/MS. Proficiency analysis confirmed method reliability, with over 50% alignment with green analytical chemistry principles. In conclusion, this study developed an environmentally sustainable sample preparation technique for seafood analysis using natural solid phases, particularly perlite, for PAH determination.

Validation of a modified QuEChERS method for the quantification of residues of currently used pesticides in Cuban agricultural soils, using gas chromatography tandem mass spectrometry.

We present an analytical method to detect and quantify residues of currently used pesticides (CUPs), which include 31 active ingredients (ai) and seven transformation products (TPs) in tropical and agricultural soils of Cuba. Ten isotopically labeled analogous compounds served as internal standards (IL-IS). The novelty of this research is the inclusion of different tropical soils type scarcely studied for CUPs and TPs, based on the QuEChERS (quick, easy, cheap, effective, rugged and safe) method, followed by chromatography tandem mass spectrometry. All figures of merit proved to be satisfactory according to SANTE guidelines 2020 and 2021. Matrix effects (ME) calculated by the external standard method were significant (|ME| > 20% for almost all compounds; grand mean ± standard deviation (STD) 104 ± 108%) in all soils. The internal standard method compensated ME to non-significant levels (8 ± 50%), even for analytes with a non-structure identical IL-IS (STD, 13 ± 57%). Repeatability (relative standard deviation, RSDr) and reproducibility (RSDR) for skeletic regosol (SR) were 7.5 ± 2.8% and 11.7 ± 4.7%, respectively. Absolute (quantified for 11 analytes with structure identical IL-IS) and relative recovery from SR was 92 ± 13% (mean ± STD) and 90 ± 12%, respectively. Limits of quantification for SR ranged from 0.1 to 10 ng/g, except metalaxyl and oxyfluorfen (25 ng/g each). Linearity of matrix-matched (MM) calibration curves (5 to 100 ng/g) had an R2 of ≥ 0.99 for all soils and almost all analytes. The method was successfully applied to 30 real soil samples.

Metabolomic analysis reveals the changing trend and differential markers of volatile and nonvolatile components of Artemisiae argyi with different aging years.

Artemisia argyi Folium (AAF) is a traditional medicinal herb and edible plant. Analyzing the differential metabolites that affect the efficacy of AAF with different aging years is necessary. The aim of the study was to investigate the changing trend and differential markers of volatile and nonvolatile metabolites of AAF from different aging years, which are necessary for application in clinical medicine. Metabolites were analyzed using a widely targeted metabolomic approach based on ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and gas chromatography tandem mass spectrometry (GC-MS). A total of 153 volatile metabolites and 159 nonvolatile metabolites were identified. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) could clearly distinguish AAF aged for 1 year (AF-1), 3 years (AF-3), and 5 years (AF-5). Seven flavonoids and nine terpenoids were identified as biomarkers for tracking the aging years. The metabolomic method provided an effective strategy for tracking and identifying biomarkers of AAF from different aging years. This study laid the foundation for analysis of the biological activity of Artemisia argyi with different aging years.

Quantifying 209 Polychlorinated Biphenyl Congeners in Silicone Wristbands to Evaluate Differences in Exposure among Demolition Workers.

A social housing estate in Denmark was designated for demolition due to exceedance of guidance values for polychlorinated biphenyls (PCBs) in indoor air. Here, we deployed precleaned silicone wristbands (n = 46) among demolition workers of these contaminated buildings during single workdays while conducting various work tasks. We established a method to analyze all 209 PCBs in wristbands to identify prominent congeners of exposure and evaluate differences between tasks. Wristbands were extracted using microwave-assisted extraction and then concentrated for gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis. Twenty-nine chromatographic peaks representing 37 congeners were detected in every wristband, and tetra-CBs were the dominant homologue group. PCB-66, -44, and -70 were the most abundant congeners measured in worker wristbands, none of which are included within the typical seven indicator or WHO 12 PCBs. Workers who cut PCB-containing sealants had wristbands with the highest PCB concentrations (geometric mean ∑209PCBs = 1963 ng/g wristband), which were followed by those handling concrete elements on the building roof. Additionally, wristbands captured a broader range of PCBs than has been previously measured in air and serum samples. Taken together, our results highlight the importance of total congener analysis in assessing current PCB exposure in demolition work and the utility of wristbands for assessing these exposures.

Multiresidue analysis of bat guano using GC-MS/MS

Bats are the second largest mammalian order and are an endangered species group with a strong need for contamination monitoring. To facilitate non-invasive monitoring of the ecological burden in bat populations, a multiresidue method for the simultaneous quantification of 119 analytes including pesticides, persistent organic pollutants (POPs), active pharmaceutical ingredients (APIs), polycyclic aromatic hydrocarbons (PAHs), UV blockers, plasticizers, and other emerging pollutants in bat guano with gas chromatography tandem mass spectrometry (GC-MS/MS) was developed. Sample preparation and clean-up were performed with a modified QuEChERS approach based on DIN EN 15662. The method uses 1.00 g bat guano as sample with acetonitrile and water for liquid-liquid extraction. Phase separation is assisted by citrate-buffered salting out agent. For clean-up of the extract, primary secondary amine (PSA) was combined with graphitized carbon black (GCB). The lower limits of quantification (LLOQ) ranged between 2.5 and 250 µg kg−1. Linearity was shown in a concentration range from the respective LLOQs to 1250 µg kg−1. The median of the mean recovery was 102.4%. Precision was tested at three concentrations. Method and injection precision were adequate with a relative standard deviation (RSD) below 20%. Furthermore, the comparative analysis with LC-MS/MS demonstrated the reliability of the results and provided a valuable extension of the analytical scope. As proof of concept, three guano samples from a German nursery roost of Myotis myotis were analysed. The results show a time-dependent change in contaminant concentration, highlighting the strong need for non-invasive contamination monitoring of whole bat populations.Graphical

Rapid determination of polyhalogenated carbazoles in water chestnut based on vortex assisted solvent extraction coupled with dispersive filter extraction followed by gas chromatography-tandem mass spectrometry

Polyhalogenated carbazoles (PHCZs), originating from the production and use of halogenated indigo dyes, photoelectric materials, and p-chloraniline structure herbicides, pose a threat to water environments, aquatic products, and consequently human health. Therefore, establishing an accurate detection method for PHCZs in aquatic products is of paramount importance. In this study, trace PHCZs (36-CCZ, 36-BCZ, and 1368-BCZ) in water chestnut were detected for the first time using the prepared polyvinyl alcohol-functionalized graphene aerogel (PGA) as a novel adsorbent for dispersive filter extraction (DFE), coupled with vortex assisted solvent extraction (VASE), followed by gas chromatography-tandem mass spectrometry (GC–MS/MS). The extraction process (VASE-DFE) has the advantages of good purification effect, short extraction time (<15 min), and low adsorbent dosage (1.0 mg). This method demonstrated excellent linearity in the range of 0.10/0.50/1.00–200 ng/g for the three PHCZs (R2 ≥ 0.9995), and the recoveries at three spiked levels (2, 20, 100 ng/g) ranged from 82 % to 93 %, with relative standard deviations (RSDs) ≤ 7.4 %. Notably, the method outperforms previously reported adsorbents in terms of RSDs, adsorbent dosage, and extraction time. The VASE-DFE-GC–MS/MS method provides a new approach for the detection of trace pollutants in complex samples, introduces a novel technology for environmental and food safety monitoring, and contributes to enhancing food safety supervision.

The Effect of Farming Techniques on Degradation of DDT in Historical Cotton Farms

DDT was used in the mid 20th century for crop and livestock production. After use, DDT and its degradates DDE and DDD (collectively DDX) remain in the environment for decades. A few studies have reported that the rate of degradation of DDT into its metabolites is affected by various farming techniques like tillage, irrigation, and use of fertilizers. However, most of these studies did not evaluate active farms, and none of them focused on the Southeast US or historical cotton farms. Therefore, in this study, we aimed to determine if different farming techniques affect the decomposition of DDT in Walton County, Georgia, where farms historically grew cotton. Five Walton County farms were sampled for soil, and churches were sampled as control sites. The extensive land history of the farms was recorded, and the soil levels of p,p’-DDT, p,p’-DDE, p,p’-DDD, o,p’-DDT, and o,p’-DDE were measured using gas chromatography-tandem mass spectrometry. All farm sites had detectable levels of p,p’-DDT, p,p’-DDE, and p,p’-DDD, while few sites had detectable levels of o,p’-DDT and o,p’-DDE. Tillage was found to speed up p,p’-DDE degradation, but there was no effect on p,p’-DDT degradation. Plowing was associated with an increase in decomposition of p,p’-DDT, but p,p’-DDE and p,p’-DDD were not significantly increased. The largest difference in the degradation of DDT was based on the fertilizer type. Natural fertilizer sped up degradation of p,p’-DDT and p,p’-DDE; synthetic fertilizer increased p,p’-DDE degradation, but not p,p’-DDT degradation.

Biocide and other semi-volatile organic compound concentrations in settled indoor dust of CRESPI daycare centers and implication for public health

This study investigates the presence of biocides and other semi-volatile organic compounds (SVOCs) in cleaning products used in daycare centers and health impact through ingestion of settled dust by young children. In Paris metropolitan, 106 daycares area were investigated between 2019-2022. Fifteen substances were analyzed in settled indoor dust by gas chromatography-tandem mass spectrometry. Detection rates and concentrations ranged from 5 to 100%, and <LOD to 14,267ng/g, respectively. Galaxolide and benzophenone showed highest median concentration respectively 884ng/g and 819ng/g. The daily intake (DI) of the substances through settled dust ingestion were evaluated and compared to those from food, inhalation, and dermal contact reported in the literature. Daily intakes from settled dust for musks, triclosan, - geraniol, benzophenone, 2-phenylphenol, bifenthrin, and 4-n-nonylphenol were lower than those reported in the literature. The proportion of dust ingestion to total DI was negligible, except for benzophenone (DI=34%) for children aged 3 to 11 months. The DIs were well below the respective toxicological reference values for isothiazolinones, 4-tert-butylphenol, chlorocresol, and diclosan. Our results suggest that exposure to these biocides and the other SVOCs, taken individually, by dust ingestion in daycares, is not a major public health concern. Benzophenone, presumed carcinogen for humans, may require further investigation because of its presence in several daycares.

Distribution of 2,2',5,5'-Tetrachlorobiphenyl (PCB52) Metabolites in Adolescent Rats after Acute Nose-Only Inhalation Exposure.

Inhalation of PCB-contaminated air is increasingly recognized as a route for PCB exposure. Because limited information about the disposition of PCBs following inhalation exposure is available, this study investigated the disposition of 2,2',5,5'-tetrachlorobiphenyl (PCB52) and its metabolites in rats following acute, nose-only inhalation of PCB52. Male and female Sprague-Dawley rats (50-58 days of age, 210 ± 27 g; n = 6) were exposed for 4 h by inhalation to approximately 14 or 23 μg/kg body weight of PCB52 using a nose-only exposure system. Sham animals (n = 6) were exposed to filtered lab air. Based on gas chromatography-tandem mass spectrometry (GC-MS/MS), PCB52 was present in adipose, brain, intestinal content, lung, liver, and serum. 2,2',5,5'-Tetrachlorobiphenyl-4-ol (4-OH-PCB52) and one unknown monohydroxylated metabolite were detected in these compartments except for the brain. Liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis identified several metabolites, including sulfated, methoxylated, and dechlorinated PCB52 metabolites. These metabolites were primarily found in the liver (7 metabolites), lung (9 metabolites), and serum (9 metabolites) due to the short exposure time. These results demonstrate for the first time that complex mixtures of sulfated, methoxylated, and dechlorinated PCB52 metabolites are formed in adolescent rats following PCB52 inhalation, laying the groundwork for future animal studies of the adverse effects of inhaled PCB52.

Metabolomic Analysis of Amino Acid and Organic Acid Profiles in Tissue From Ovarian Cancer Patients Using High-Performance Liquid Chromatography-Tandem Mass Spectrometry (HPLC-MS/MS) and Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS)

Targeted metabolomics studies on organic acids (OAs) and amino acids (AAs) were performed to search for biomarkers for ovarian cancer progression. Simultaneous AA profiling analysis method was developed through LC-MS/MS. Under optimal conditions, method showed good linearity (r ≥ 0.998) with limits of detection (LOD) ≤ 0.22 ng/mL and limits of quantification (LOQ) of ≤0.72 ng/mL. Repeatability varied from 1.4 to 17.3 relative standard deviation (%RSD) and accuracy varied from −20.6% to 12.1% relative error (% RE). Twenty-six AAs and 13 OAs were detected in the analyses of ovarian tissue from patients with benign ovarian tumors (BOT), borderline tumors (BT), and ovarian serous carcinoma (OSC). Star pattern recognition analysis was performed by normalizing each group to the BOT group. The star symbol plots in the BT and OSC groups were distinct and easily distinguished from those in the BOT group. The BT and the OSC groups exhibited higher 3-hydroxybutyric acid and lactic acid levels, lower pyruvic acid and OA levels in the TCA cycle, and alterations in AA metabolic patterns in comparison to the BOT group. Especially, citrulline and leucine were significantly reduced, while fumaric acid and malic acid significantly increased in the OSC group compared to the BT group. The BT and the OSC groups were completely separated in orthogonal partial least squares-discriminant analysis (OPLS-DA) and heatmap analysis. These findings, elevated ketone body levels, increased anaerobic glycolysis, reduced energy production related to mitochondrial dysfunction in the TCA cycle, and AA metabolic patterns associated with the impaired antioxidant system, may explain the characteristic metabolic reprogramming and Warburg effect related to the progression of the OSC into malignancy.

A three-dimensional hierarchical porous graphene aerogel as a fiber coating for headspace solid-phase microextraction: Enhancing the enrichment and detection of polychlorinated naphthalenes in fish

In this study, a novel three-dimensional hierarchical porous deep eutectic solvents-modified graphene aerogel (3D DES-GA) was synthesized for use as a solid-phase microextraction (SPME) fiber coating. The SPME fiber was characterized by its fluffy and hierarchical porous structure, uniform thickness, and rapid mass transfer capabilities. This fiber demonstrated a lifetime (≥160 uses) and excellent precision (with relative standard deviations of 2.4–6.6% for single fiber and 6.0–9.8% for fiber-to-fiber repeatability). The SPME fiber also exhibited remarkable extraction performance for polycyclic aromatic hydrocarbons and polychlorinated biphenyls, which are common persistent organic pollutants in environmental samples. When combined with gas chromatography-tandem mass spectrometry, the method allowed for high-efficiency extraction (enrichment factors ranging from 1225 to 4652 folds) and sensitive determination (limit of detection ranging from 0.010 to 0.056 pg g−1) of polychlorinated naphthalenes (PCNs) in complex samples. To validate this method, we applied it to the determination of four PCNs in five types of fish tissues. The results revealed the presence of 1-chloronaphthalene at concentrations of 7.0 ± 2.9–34.8 ± 2.1 pg g−1 and 1,4-dichloronaphthalene at concentrations of 6.0 ± 0.3–10.9 ± 1.4 pg g−1 in three fish species. Compared with reported sample pretreatment methods reported in the literature, this proposed headspace SPME method offers additional advantages, including simplicity of operation and reduced sample and organic solvent consumption.

Impact of Washing and Fermentation on the Concentration of Pesticide Residues in Nigerian Staple Foods By IJISRT

The use of pesticides in agriculture is linked to accumulation of toxic compounds in the soil, in food, and its accumulation in animal and human tissues. Pesticide residues are deposits of pesticides that remain on or in agricultural produce after harvest or during storage. This work examined the effects various processing steps on the levels of methoxychlor, dieldrin, p,p’-DDE and α- chlordane residues in common staples; maize, rice, beans and cassava. The treatments administered included cold water washing, hot water washing, and fermentation for 3 and 5 days. The Quick, Effective, Cheap, Easy, Rugged and Safe (QuEChERS) technique was adopted for extraction of pesticide residues while gas chromatography tandem mass spectrometry was used for quantification of the residues in the samples. The processing steps applied had various effects on the level of residues ranging from - 149% to 100% reduction in level of pesticide; in rice processing, washing with hot water had the greatest impact in reducing methoxychlor (55.5-97.1%) and α- chlordane (95.5%). Fermentation for 5 days had the greatest impact in reducing methoxychlor residue from cassava (13.6-26.3%), while fermentation of maize for 3 or 5 days had similar impact in reduction of the level of methoxychlor (35.5-79.5% and 39.1-78.4% respectively) and α-chlordane (100% and 100% respectively). Hot water washing of beans was most effective in eliminating methoxychlor (98.4%), p,p’-DDE (100%), α-chlordane (100%) and dieldrin (100%). Reduction in hazard index was also observed with processing, as a result of reduction in amount of pesticide going into the diet.

Determination of penicillic acid in cereals by solid-phase extraction and gas chromatography-tandem mass spectrometry

A gas chromatography-tandem mass spectrometry (GC−MS/MS) method was established for accurately determining penicillic acid in cereals. The cereal samples were extracted using acidified acetonitrile, purified by solid-phase extraction, and derived using N,O-bis(trimethylsilyl) acetamide for GC−MS/MS analysis. Recovery experiments were conducted with low, medium, and high concentrations. The recovery rates were 72.1%–89.8%, the relative standard deviations were less than 8.6%, and the limit of quantification was 20 μg/kg. The established method was rapid, efficient, sensitive, and specific, meeting the requirements for the determination of penicillic acid in cereals. The method exhibits high sensitivity, accurate results, and stable recovery, making it suitable for detecting penicillic acid residues in cereals.

Length-controlled hydrophobic CF3-COF as a highly efficient absorbent coating for dual-mode solid-phase microextraction of sixteen polycyclic aromatic hydrocarbons in water samples

Polycyclic aromatic hydrocarbons (PAHs), a group of seriously hazardous environmental contaminants, have attracted extensive attention due to their carcinogenicity, genotoxicity, mutagenicity, and ubiquity. In this work, the excellent hydrophobic trifluoromethyl-enriched covalent organic framework (CF3-COF) was designed and synthesized as coating of solid-phase microextraction (SPME). The CF3-COF offered a high adsorption selectivity for PAHs, which could be attributed to the multiple interactions between the CF3-COF and PAHs, including hydrophobicity interaction, π-π and H bond interactions. Furthermore, headspace (HS) and direct immersion (DI) dual-mode solid-phase microextraction (HS/DI-SPME) were innovatively integrated as a dual-mode extraction by varying the length of SPME coating on stainless-steel, which could simultaneously and efficiently extract 16 PAHs with different volatile. Amazingly, the proposed strategy achieved fast adsorption for PAHs and shortened the adsorption equilibrium time to 15 min. By further integrating with gas chromatography tandem mass spectrometry (GC–MS/MS), PAHs could be detected in the range of 0.008–0.16 ng mL−1 with a quantitative limit of 0.029–0.47 ng mL−1, respectively. The recoveries of PAHs in water samples ranged from 80.84 to 117.67 %. This work indicates that the dual-mode CF3-COF-SPME is a promising candidate for the enrichment of multiple hazardous substances in complicated samples.

A Selective Gas Chromatography–Tandem Mass Spectrometry Method for Quantitation of Ethylene and Diethylene Glycol in Paediatric Syrups

Ethylene Glycol (EG) and diethylene Glycol (DEG) are two contaminants known to cause various human health problems. These glycols might be present in drug syrups that are based on glycerol, sorbitol, or polyethylene glycol. In late 2022, several batches of cough, antipyretics, and antihistamine syrups were reported to contain toxic levels of EG and DEG in multiple countries; this incident concerned the World Health Organization (WHO). From an analytical perspective, several methods of glycols analysis in pharmaceuticals have been reported in the literature, with the majority being dedicated to raw material analysis. This study aims to develop a selective method capable of evaluating a wide range of paediatric syrups in order to assess the safety of commercially available paediatric syrups currently distributed in the local market. This research introduces a method for determining glycols utilizing gas chromatography-tandem mass spectrometry (GC–MS/MS), which offers significantly higher selectivity than conventional single quadrupole gas chromatography-mass spectrometry (GC–MS). The developed method meets the current International Council for Harmonisation (ICH) guidelines for validation. The absence of any interfering peaks in both the unspiked sample of promethazine syrup and the reference standard solutions proved the method's selectivity. Furthermore, 2,2,2-trichloroethanol was used as an internal standard, and a new GC–MS/MS method was developed to analyze it. The calibration curves for EG and DEG were linear within the selected concentration range of 1–10 μg/mL. The detection limit for both EG and DEG was 400 ng/mL, while the quantification limit was 1 μg/mL. Recovery values for both EG and DEG met the accuracy acceptance criterion. Thus, the developed method proved to be efficient and accurate for determining EG and DEG levels in suspected contaminated syrups.

[Determination of 35 prohibited pesticide residues in Saussurea costus by modified QuEChERS method based on multi-walled carbon nanotubes coupled with gas chromatography-tandem mass spectrometry].

Saussurea costus, a perennial herb belonging to the Asteraceae family, is a vital ingredient in traditional Chinese medicine. Increased demands for the herb have led to its widespread cultivation in China, but the corresponding increase in pesticide use has raised concerns about pesticide residues. Such residues would affect the safety and global market potential of Saussurea costus. Thus, a simple method is crucial to detect pesticide residues. The QuEChERS technique, in combination with gas chromatography-tandem mass spectrometry (GC-MS/MS), is commonly used for residue detection. However, traditional adsorbents may be unable to purify complex herbal mixtures well, affecting accuracy and instrument performance. Choosing suitable purification materials for Saussurea costus samples with complex matrices is of significant importance. This study focused on the detection of 35 prohibited pesticides in Saussurea costus. A rapid detection method was established by combining the QuEChERS technique with GC-MS/MS and utilizing a combination of multiwalled carbon nanotubes (MWCNTs), octadecylsilane-bonded silica gel (C18), and anhydrous magnesium sulfate (MgSO4) as the purification adsorbent. The samples were extracted with acetonitrile, purified by an improved QuEChERS process, subjected to GC-MS/MS analysis in multiple reaction monitoring (MRM) mode, and quantified using the internal standard method. The purification effects of four materials (C18, MWCNTs, N-propyl ethylenediamine (PSA), and graphitized carbon black (GCB)) and their optimal dosages were investigated by considering the matrix characteristics of the samples. An orthogonal experimental design was employed to optimize the ratio of adsorbent combinations, and the optimal adsorbent combination was determined to be 450 mg of MgSO4, 400 mg of C18, and 50 mg of MWCNTs. Matrix effect (ME) evaluation of the S. costus matrix showed that 31 target compounds strongly exhibited matrix-enhancement effects. Thus, matrix-matched calibration was employed in this study. Methodological investigation revealed that the standard curves for the 35 pesticides exhibited good linearity, with correlation coefficients (r2) greater than 0.9970. The average recoveries at three spiked levels ranged from 69.6% to 126.9%, and the relative standard deviations (RSDs) for parallel groups were all less than 10%. The limits of detection (LODs) and quantification (LOQs) ranged from 0.2 to 5.4 μg/kg and from 0.6 to 18.1 μg/kg, respectively. The developed method was used to screen and detect 35 pesticide residues in 20 batches of S. costus samples, and the target compounds were detected in six batches. The proposed method is simple, sensitive, and accurate. Thus, it is suitable for the rapid screening and detection of the 35 pesticide residues in S. costus and provides technical support for the cultivation, production, and quality control of the herb.

Structural Characterization and In Vitro Antioxidant Activity of a Novel Polysaccharide from Summer-Autumn Tea.

To enhance the utilization of summer-autumn tea, a water-soluble polysaccharide (D1N1) was isolated through a series of techniques including hot water extraction, ethanol precipitation, and column chromatography. The structure of D1N1 was determined through the utilization of ultraviolet, Fourier-transform infrared, high-performance anion-exchange chromatography, gas chromatography-tandem mass spectrometry, and nuclear magnetic resonance. The results revealed that glucose was the predominant component of D1N1, accounting for 95% of its composition. Additionally, D1N1 also contained galactose, arabinose, and rhamnose. The molecular weight (Mw) of D1N1 was determined to be 224.71 kDa. The backbone of D1N1 consisted of →4)-α-D -Glcp (1→, →3,4)-α-D-Galp-(1→, →4,6)-α-D -Glcp (1→ at a molar ratio of 35:1:1, and branching at the O-3 position of →3,4)-α-D-Galp-(1→ and O-6 position of →4,6)-α-D-Glcp (1→ with α-D -Glcp (1→. In addition, the antioxidant activity of D1N1 was also evaluated. D1N1 exhibited excellent antioxidant bioactivity against the DPPH, superoxide anion radical, and ABTS+ radical. These findings provide a theoretical basis for the application of summer-autumn tea polysaccharide as a potential functional food.