Chromatography-triple Quadrupole Tandem Mass Spectrometry Research Articles

The variation of odor characteristics of wastewater sludge treated by advanced anaerobic digestion (AAD) and the contribution pattern of key odorants

Identification of the odor characteristics of wastewater sludge is important in the evaluation of sludge quality and disposal options considering that sludge odor nuisance may cause major environmental issues. In this study, raw sludge and sludge cake were collected from five WWTPs applied advanced anaerobic digestion (AAD) sludge treatment process to clarify the variation of odor characteristics using sensory analysis and instrumental analysis. The electronic nose, gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-triple quadrupole tandem mass spectrometry (GC–MS/MS) were used to profile and identify the chemical composition of key odorants. A total of 20 odorants were identified and quantified, including 6 groups of chemicals, among which volatile sulfur compounds (VSCs), indole, 3-methylindole and geosmin were identified as key odorants. The odor of the dewatered digested sludge was improved by means of changing the odor character from fecal/sulfide to earthy odor due to the reduction in VSCs concentration. The AAD and subsequent dewatering process resulted in effective removal of VSCs, which are important constituents that impact the sludge odor characteristics through synergistic effect on fecal odorants and masking effect on earthy odorants. Moreover, due to the variation of sludge quality after AAD treatment, the emission capacity of indole, 3-methylindole, and other volatiles increased, which could not be neglected for the formation of unique sludge odor.

Carbon Isotope Composition and Geochemical Features of Sediments From Gongga Mountain, China, and Potential Environmental Implications

Using gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS), the soluble organic matter was analyzed for the first time in twenty-two sediment samples from the eastern slopes of the Gongga Mountain, China, at high altitudes between 4,600 and 6,700 m. The C11-C33n-alkanes and C9-C33n-alkan-2-ones were identified in these samples. Both compounds were dominated by odd carbon numbers in the long-chain molecules and contained a maximum of n-C27 or n-C29, indicating that the sediments were predominantly of higher plant origin. However, the short-chain n-alkan-2-ones, with a maximum content of n-C17 or i-C18 (phytone, 6, 10, 14-trimethylpentadecan-2-one), did not show a predominance of odd and even numbers, suggesting that they were predominantly derived from bacteria and algae. Therefore, we suggest that the organic matter in Gongga Mountain comes from three sources, i.e. bacteria, algae, and higher plants. Stable carbon isotope (δ13C) values ranged from −24.6‰ to −27.3‰, indicating that C3 plants were the dominant organic input to the sediments and suggesting a relatively colder and drier depositional environment. However, C4 plants increase sharply at high altitudes of 6,300–6,600 m, suggesting that the paleoclimate of Gongga Mountain became drier and wetter with the increase of altitude.

Characterization of aroma-active compounds in Dongli by quantitative descriptive analysis, gas chromatography-triple quadrupole tandem mass spectrometry, and gas chromatography-olfactometry.

The online version contains supplementary material available at 10.1007/s13197-022-05463-8.

Characterization of N,O-heterocycles in green tea during the drying process and unraveling the formation mechanism

N,O-Heterocycles play an important role in the characteristic flavor of green tea owing to their strong odors and low odor thresholds. In this study, a rapid and sensitive method was developed to determine seven N,O-heterocycles in green tea by using headspace solid-phase microextraction Arrow (HS-SPME-Arrow) coupled with gas chromatography-triple quadrupole-tandem mass spectrometry. The HS-SPME-Arrow extraction was performed using a Carbon WR SPME Arrow fiber. Good linear ranges (5–1000 ng/mL) were obtained, with correlation coefficients (R2) higher than 0.99 for all target compounds. LODs and LOQs were in the range of 0.44–5.12 and 1.48–17.04 μg/kg, respectively. The recoveries of seven N,O-heterocycles were found to vary from 83.1% to 117.3%, with RSDs being lower than 10%. The dynamic changes of N,O-heterocycles during the drying process revealed that 25- and 40-min-long drying processes were key transition points. Furfural could be used as a key indicator compound for evaluating the extent of the drying. Moreover, furfural and 2-methylfuran revealed a significant positive correlation with proline (p < 0.05). The possible formation mechanisms of N,O-heterocycles were further elaborated by simulated Maillard reactions. Our results provide a theoretical foundation for the improvement and directional regulation of aroma quality of green tea during manufacturing.

Simultaneous focused ultrasound solid–liquid extraction and dispersive solid-phase extraction clean-up for gas chromatography–tandem mass spectrometry determination of polycyclic aromatic hydrocarbons in crustacean gammarids meeting the requirements of the European Union Water Framework Directive

The study presents the development and validation of a method for the determination of seven priority polycyclic aromatic hydrocarbons (PAHs, including fluoranthene and benzo[a]pyrene, for which the EU has set environmental quality standards, EQS, for biota) in gammarid samples combining focused ultrasound solid–liquid extraction and dispersive solid-phase extraction clean-up in one step followed by gas chromatography–triple quadrupole tandem mass spectrometry (GC–QqQ-MS/MS). The method is designed to analyse small about 100 mg dry weight (dw) samples obtained after lyophilisation of 500 mg wet weight (ww) samples. The sample preparation procedure is simple, environment friendly (method was classified as “an excellent green analysis” according to the analytical Eco-Scale assessment), non-laborious and low-cost and, apart from the sample extract concentration step, is quick. Thorough disintegration of the gammarids is achieved by a combination of sonication and the addition of granular anhydrous Na2SO4 to the gammarid suspension, thus avoiding the need to grind the sample prior to analysis. The QqQ-MS/MS detector, thanks to its excellent selectivity and sensitivity, allows to meet the EQS requirements for PAHs in biota with a good margin (limits of quantification in the range of 0.12 and 0.56 ng g‒1 ww). The method has been successfully validated (in terms of linearity, method limits, precision, trueness, robustness, measurement uncertainty and comparative analysis of real samples), and has been shown to be suitable for monitoring and evaluating the PAHs contamination in surface water biota.

High quality standard of Scutellariae Radix based on plant metabolomics and index components

Scutellariae Radix(SR), derived from the dried root of Scutellaria baicalensis in the family Lamiaceae, commonly serves as Chinese medicinal material. Affected by producing areas, growing years, and harvesting periods, the quality of SR fluctuates in the market. However, baicalin≥9% in SR required in the Chinese Pharmacopoeia(2020 edition) can only determine the qualified SR but cannot identify high-quality SR. To improve the quality control methods of SR, the present study analyzed the accumulation of metabolites in SR of different growth years by plant metabolomics, and identified 28 metabolites increasing with growth years(1-3 years). Subsequently, 14 main metabolites were quantitatively analyzed by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry(UPLC-QQQ-MS). Among them, baicalin, wogonoside, baicalein, and wogonin with high content and good activity were selected as the index components of SR for quality evaluation. A high-performance liquid chromatography(HPLC) method was established to determine the content of four index components in 32 batches of SR from different producing areas, harvesting perio-ds, and growth years. The results showed that the growth years could greatly affect the content of index components. The total content of four index components in 2-year SR was the highest, followed by the 3-/4-year SR and 1-year SR. Based on HPLC data and verification results by enterprises, baicalin ≥12.0%, wogonoside ≥2.3%, baicalein ≥0.1%, and wogonin ≥0.03% were proposed as the evaluation criteria for the high-quality SR. The findings of this study are expected to provide a basis for improving the quality of SR.

A UHPLC-QTOF-MS/MS method with a superimposed multiple product ion strategy and esterase inhibitor improved sensitivity for the determination of xylocarpin H in rat plasma

Xylocarpin H is a natural limonoid that has the potential to be a viable therapeutic candidate whether used alone or in combination with other medications. However, the pharmacokinetic properties of xylocarpin H are still not well understood and require further investigation. Sensitive analysis of xylocarpin H using liquid chromatography tandem triple-quadrupole mass spectrometry is challenging due to its structural feature. In the present research, a sensitive UHPLC-QTOF-MS/MS method was developed and validated to determine xylocarpin H in rat plasma. After simple methanol protein precipitation pretreatment with 50 mM esterase inhibitor bis(4-nitrophenyl)-phosphate (BNPP), xylocarpin H and Schisandrin (internal standard) were separated on a Synergi 4 u fusion-RP C18 column (50 mm × 3.0 mm, 4 µm) using isocratic elution with a mobile phase consisting of formic acid (0.1%) and acetonitrile, which were detected only within 3 min. The QTOF-MS/MS detection, which is a high-resolution mode, can accurately quantify analytes (ppm<5). The peak area of xylocarpin H was determined by adding the single peak areas of m/z 483.2013, m/z 465.1930 and m/z 345.1333 as the superimposed multiple product ions (SMPI) mode for data processing with optimized the high-resolution extraction widths of fragment ions at ± 0.05 Da. The S/N of the SMPI mode was found to be approximately two to seven times greater than the independent product ion mode. The linearity, precision, accuracy, and stability were completely validated for the method. Finally, the validated method was employed for the pharmacokinetic study of xylocarpin H in rats. The study indicated that the optimized high-resolution extraction widths of fragment ions and SMPI mode for data processing significantly improve the quantitative sensitivity of QTOF-MS/MS. In addition, esterase inhibitor BNPP was added in the process of sample treatment to inhibit the degradation of xylocarpin H in rat blood, which further improved the sensitivity of the quantitative method.

Simultaneous Determination of Levamisole, Mebendazole, and the Two Metabolite Residues of Mebendazole in Poultry Eggs by High-Performance Liquid Chromatography–Tandem Mass Spectrometry

The quantitative determination of levamisole (LMS), mebendazole (MBZ), and the two metabolites of MBZ, 5-hydroxymebendazole (HMBZ) and 2-amino-5-benzoylbenzimidazole (AMBZ), in poultry eggs (hen, duck, and goose) was achieved with high-performance liquid chromatography–tandem triple quadrupole mass spectrometry (HPLC–MS/MS). Samples were pretreated by liquid–liquid extraction and solid-phase extraction (LLE–SPE) to extract the target compounds, and an Oasis MCX SPE column was used for purification. Determination was performed on an Xbridge C18 column with 0.1% formic acid aqueous solution and acetonitrile as mobile phases. LMS, MBZ, HMBZ, and AMBZ were detected in a triple-quadrupole mass spectrometer with ESI in positive mode and quantified with an external standard. In blank eggs, the target analyte concentrations were within the limits of quantification (LOQs)—25 μg/kg (LMS) and 150 μg/kg (MBZ, HMBZ, and AMBZ)—and the matrix-matched calibration curves had good linearity (R2 ≥ 0.9990). In the same concentration range, the average recoveries of the target analytes were 85.98–97.38% (n = 6); the relative standard deviation (RSD), intraday RSD, and interday RSD ranged from 2.06 to 4.22%, 1.40 to 5.85%, and 2.34 to 6.32%, respectively. The limits of detection (LODs) ranged from 0.03 to 0.33 µg/kg, and the LOQs ranged from 0.08 to 1.00 µg/kg. Experimental verification showed that the HPLC–MS/MS method exhibited high specificity and sensitivity for quantitative analyses of egg samples. This study provides a rapid, efficient, and sensitive method for the simultaneous detection of LMS, MBZ, HMBZ, and AMBZ residues in foods of animal origin.

A facile molecularly imprinted column coupled to GC-MS/MS for sensitive and selective determination of polycyclic aromatic hydrocarbons and study on their migration in takeaway meal boxes

The analysis of toxic and harmful substances in food has attracted significant attention. In this work, a molecularly imprinted column coupled to gas chromatography-triple quadrupole tandem mass spectrometry method (MIC-GC-MS/MS) method for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in takeaway meal boxes was established by comparing the extraction results of 16 PAHs with 5 different sample pretreatment techniques, and the effects of food types and storage conditions on the migration of PAHs was studied by migration test. The conditions of extraction and chromatography-mass spectrometry were optimized. The results showed that the linear ranges were in the wide range of 1–100 ng mL−1 for 16 PAHs, with the correlation coefficients (R) higher than 0.9983; the detection limits (LODs) and the limits of quantification (LOQs) were in the range of 0.08–0.42 μg kg−1 and 0.24–1.26 μg kg −1, respectively; the spiked recoveries at three levels of 10, 20, 30 μg kg−1 were in the range of 86.2%–107.7% with the relative standard deviation (RSD) less than 7.8%. Therefore, this method had high sensitivity and good reproducibility and was suitable for the determination of 16 PAHs in food contact materials. The migration test of PAHs showed that the migration amount of PAHs in takeaway meal boxes was closely related to food types, and the migration amount was positively correlated with contact temperature and contact time in a certain range.

A QuEChERS-based UPLC-MS/MS method for rapid determination of organophosphate flame retardants and their metabolites in human urine

Organophosphate flame retardants (OPFRs) have been widely used in consumer products to prevent fire spread. However, once released into the atmospheric environment, they may accumulate in humans and undergo metabolic transformation and excretion by urine. In order to clarify the human exposure to OPFRs, a quick, easy, cheap, effective, rugged, and safe method for the simultaneous determination of urinary OPFRs and their metabolites by ultra-performance liquid chromatography-tandem triple quadrupole mass spectrometry was developed. After the optimization by a single-factor or orthogonal experiment, the satisfactory recovery (87.8–119%), matrix effect (−8.88–9.29%), method quantitation limit (3.66–159 ng/L), and inter-day repeatability (1.24 − 10.6%) of most analytes were achieved in artificial urine samples. Based on a monitoring test by the developed method, we propose that urinary bis(1-chloro-2-propyl) phosphate and di-p-cresyl phosphate could be used to trace human exposure to tris(1-chloro-2-propyl) phosphate and tricresyl phosphate, respectively. Most importantly, this is the first study to reveal that 4-hydroxyphenyl diphenyl phosphate (4-OH-TPHP) was dominantly presented in its conjugated form rather than its free form in urine (p = 0.037). Overall, the obtained results contribute a relatively rapid method to help conduct large-scale urine monitoring for revealing the human exposure and risk of OPFRs.

Glycerophospholipid metabolism is involved in rheumatoid arthritis pathogenesis by regulating the IL-6/JAK signaling pathway

To explore the metabolic mechanism of differential plasma interleukin (IL)-6 expression in patients with rheumatoid arthritis (RA). A total of 240 RA patients were enrolled in the non-target metabolomics study cohort and 69 healthy volunteers were included as healthy controls (HCs). Plasma IL-6 levels were detected by electrochemiluminescence assay. Plasma metabolites were detected by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Patients with active RA (n = 20) and remissive RA (n = 20) and 20 HCs were enrolled in the targeted validation cohort. Metabolites identified by non-target metabolomics were quantitatively analyzed by ultra-performance liquid chromatography-triple quadrupole tandem mass spectrometry. Effects of 1-oleoyl-sn-glycero-3-phosphocholine (OGPC) associated with IL-6 on MH7A cells were assessed. After 24-h or 48-h induction by TNF-α, the supernatants were collected for IL-6 quantification by enzyme-linked immunosorbent assay. Furthermore, Western blot was performed to investigate the relative JAK2 and p-JAK2 expressions. With an increasing IL-6 level, OGPC shown to be related to the glycerophospholipid metabolism pathway by Kyoto Encyclopedia of Genes and Genomes analysis displayed a significant decrease. In the validating RA cohort, the OGPC concentrations in remissive RA group and active RA group decreased compared with HC group. OGPC down-regulated IL-6 secretion and p-JAK2 expression in TNF-α-induced MH7A cells in vitro. In conclusion, glycerophospholipid metabolism is the main metabolic pathway associated with the differential IL-6 expression in RA patients. The down-regulated OGPC is a promoting factor for the increased IL-6 plasma level in RA patients, which further affects the downstream JAK signaling pathway.

Pollution Characteristics and Risk Assessment of Nitrated Polycyclic Aromatic Hydrocarbons in the Atmosphere of Guangdong-Hong Kong-Macao Greater Bay Area

To investigate the pollution characteristics and sources of nitrated polycyclic aromatic hydrocarbons (NPAHs) in Guangdong-Hong Kong-Macao Greater Bay Area (GBA), 44 ambient air samples were collected using the active sampling method, which were then determined via gas chromatography-triple quadrupole tandem mass spectrometry. The main results showed that filters, polyurethane foam, and XAD-2 resin were the essential materials for sampling NPAHs in ambient air in order to characterize the pollution status accurately. The levels of ρ(Σ18NPAHs) in ambient air at GBA ranged from 162 pg·m-3 to 2094 pg·m-3, and the average levels of ρ(Σ18NPAHs) were (675±430) pg·m-3 in summer and (637±349) pg·m-3 in winter. NPAHs were widely found in the ambient air of GBA and were dominated by 1-nitronaphthalene (220 pg·m-3), 2-nitronaphthalene (146 pg·m-3), 9-nitroanthracene (105 pg·m-3), and 2-nitrofluoranthene (72 pg·m-3). The congener profile characteristics of NPAHs in summer and winter were similar. The gas/particle partitioning characteristics of NPAHs revealed that dicyclic and tricyclic NPAHs tend to occur in the gas phase, and tetracyclic NPAHs tend to be adsorbed in the particle phase. The fraction of NPAHs concentrations in the particulate fraction of their total atmospheric concentrations increased with the increase in their molecular weight. In winter, NPAHs tend to be adsorbed in the particle phase, whereas in summer, NPAHs tend to exist in the gas phase. Based on the ratios of characteristic pollutants, in both the summer and winter season, photochemical reactions were the main source of NPAHs in the atmosphere of GBA and were primarily generated by the reaction of the hydroxyl radical in the daytime. The carcinogenic risk value calculation showed that the current carcinogenic risk of NPAHs in the ambient air of GBA was controllable.

Method Development for Determination of Polyhalogenated Carbazoles in Industrial Waste Through Gas Chromatography-Triple Quadrupole Tandem Mass Spectrometry

Method Development for Determination of Polyhalogenated Carbazoles in Industrial Waste Through Gas Chromatography-Triple Quadrupole Tandem Mass Spectrometry

In Vitro Evaluation of DNA Damage Effect Markers toward Five Nitrogen Mustards Based on Liquid Chromatography-Tandem Mass Spectrometry.

Endogenous DNA lesions frequently occur due to internal effects such as oxidative stress, inflammation, endogenous alkylation, and epigenetic modifications. However, exposure to chemical toxicants from the environment, diet, or drugs can also induce significant endogenous DNA damage. The quantification of endogenous DNA damage effect markers might reflect the actual DNA damage level of chemical toxicants. Herein, we report a liquid chromatography-triple quadrupole tandem mass spectrometry (LC-QqQ MS/MS) method for simultaneous determination of eight representative endogenous DNA damage biomarkers, including five endogenous DNA damage effect markers (oxidative damage, 8-oxo-dG; lipid peroxidation, εdA and N2-Et-dG; inflammation, 5-Cl-dC; and endogenous alkylation, O6-Me-dG), and three epigenetic modifications (5-m-dC, 5-hm-dC, and N6-Me-dA). The method validation was performed, and the linear range was 0.05 pg to 2 ng (on-column), the limit of detection was 0.02 pg (on-column), and the precision, accuracy, matrix effect, and recovery were all between 85 and 115%. We then applied this method to evaluate endogenous DNA damage to human embryonic lung fibroblast cells exposed to five nitrogen mustards [NMs, i.e., HN1, HN2, HN3, chlorambucil (CB), and cyclophosphamide (CTX)], where curcumin exposure was used as a control due to its inability to induce the formation of endogenous DNA adducts. The amounts of eight DNA adducts in the low-, middle-, and high-concentration exposure groups of five NMs were almost all significantly different from those in the blank group (P < 0.05). We obtained a positive correlation between the contents of eight DNA damage biomarkers and the inhibition dose of five NMs, except for N2-Et-dG and 5-Cl-dC. Via further principal component analysis and partial least squares discriminant analysis, we clustered all NMs into three units with different cytotoxicity levels, that is, HN2 and HN1 (highly toxic), HN3 and CB (moderately toxic), and CTX (less toxic). Moreover, for the same concentration of HN1/2/3 exposure groups, as the cytotoxicity increased according to the order of HN3 < HN1 < HN2, the contents of 8-oxo-dG, 5-m-dC, 5-hm-dC, and N6-Me-dA increased, whereas the content of O6-Me-dG decreased. Therefore, the contents of these DNA damage effect markers were somewhat related to the cytotoxicity and concentration of NMs. We hope that this method will provide an alternative evaluation approach for the toxicological effects of NMs and the safety of the medication.

Selective Plate-Based Assay for Trace EDTA Analysis via Boron Trifluoride-methanol Derivatization UHPLC-QqQ-MS/MS Enabling Biologic and Vaccine Processes.

The employment of ethylenediaminetetraacetic acid (EDTA) across several fields in chemistry and biology has required the creation of a high number of quantitative assays. Nonetheless, the determination of trace EDTA, especially in biologics and vaccines, remains challenging. Herein, we introduce an automated high-throughput approach based on EDTA esterification in 96-well plates using boron trifluoride-methanol combined with rapid analysis by ultra-high-performance liquid chromatography-triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS). Derivatization of EDTA to its methyl ester (Me-EDTA) serves to significantly improve chromatographic performance (retention, peak shape, and selectivity), while also delivering a tremendous enhancement of sensitivity in the positive ion mode electrospray ionization (ESI+). This procedure, in contrast to previous EDTA methods based on complexation with metal ions, is not affected by high concentration of other metals, buffers, and related salts abundantly present in biopharmaceutical processes (e.g., iron, copper, citrate, etc.). Validation of this assay for the determination of ng·mL-1 level EDTA in monoclonal antibody and vaccine products demonstrated excellent performance (repeatability, precision, and linear range) with high recovery from small sample volumes while also providing an advantageous automation-friendly workflow for high-throughput analysis.

Miniaturized QuEChERS based sample preparation method combined with gas chromatography–tandem mass spectrometry for the determination of selected polycyclic aromatic hydrocarbons in crustacean gammarids

The study presents a new miniaturized and low-cost sample preparation method combined with gas chromatography–triple quadrupole tandem mass spectrometry (GC–QqQ-MS/MS) analysis developed to determine selected polycyclic aromatic hydrocarbons (PAHs: (naphthalene – Nap, acenaphthene – Ace, anthracene – Ant, fluoranthene – Flu, and benzo[a]pyrene – BaP) in dried gammarid samples. The sample preparation involved modification of the so-called QuEChERS (stands for quick, easy, cheap, effective, rugged, and safe) method followed by use of a novel combination of dispersive liquid–liquid microextraction (DLLME) and treatment with H2SO4 solution, which allowed further purification and concentration of the extract and solvent exchange without the need for solvent evaporation. The QqQ-MS/MS detector operating in the pseudo-MRM mode was used to detect PAHs with increased sensitivity compared to the classical quadrupole MRM technique. The method was validated in terms of linearity and range, detection and quantification limits (LOD and LOQ), matrix effect, recovery and precision for the analysis of 200 mg samples of dried freshwater shrimps Gammarus pulex. The LOQs for the target PAHs ranged from 4.7 to 6.3 ng g−1 dw (dry weight) or after applying the conversion factor of 0.2 (dw/ww) from 0.94 to 1.3 ng g−1 ww (wet weight). The recovery for all the analytes was in the range 72–104% and repeatability (precision) expressed by relative standard deviation in the range 1–10%. The developed method has been shown to be suitable for the purpose of monitoring and controlling compliance with environmental quality standards (EQS, set by the EU) for Flu and BaP in surface water biota.

Liquid-liquid extraction combined with online cleanup for the simultaneous determination of PAHs by GC–MS/MS and their hydroxylated metabolites by LC-MS/MS in human fingernails

A method was developed for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs) and their hydroxylated metabolites (OH-PAHs) in human fingernails using liquid–liquid extraction and online purification. After surface decontamination by rinsing with acetone, the fingernails were digested with sodium hydroxide and subjected to liquid–liquid extraction with a mixture of n-hexane and methyl tertbutyl ether. The organic extract was then fractionated using a silica-based solid-phase extraction (SPE) cartridge to obtain a PAH fraction eluted with n-hexane/dichloromethane (v/v, 95:5) and an OH-PAH fraction eluted with dichloromethane/ethyl acetate (v/v, 50:50). The PAH fraction was directly injected into an online gel permeation chromatography-gas chromatography-triple quadrupole tandem mass spectrometry (GPC-GC–MS/MS) system, enabling rapid determination of 16 PAHs. A parallel online SPE liquid chromatography tandem mass spectrometry (LC-MS/MS) method was used to determine 12 OH-PAHs. Validation experiments showed that the recovery of PAH and OH-PAH were within range of 67.4%−105.1% (RSD ≤ 10.1%) and 72.8%−102.3% (RSD ≤ 10.9%), respectively, with limits of quantitation (LOQ) of 0.06–0.8 ng/g and 0.15–3.1 ng/g, respectively. Forty-two human fingernail samples from residents of Southern China were analyzed to establish background PAH and OH-PAH levels in this region. Several PAHs and OH-PAHs were detected, at concentrations of 97.5 to 3,687 ng/g for PAHs and 24.2 to 767 ng/g for OH-PAHs. The dominant homologues were two- and three-ring PAH isomers, notably naphthalene (Nap), fluorene (Flu), and phenanthrene (Phe), as well as the corresponding hydroxylated metabolites 2-OH-Nap, OH-Flu, and OH-Phe. Smoking, consuming barbecued food, and age had no significant effects on PAH exposure, but a larger sample would be required to confirm this finding. The online purification strategy presented here expedites cleanup and purification during analysis of human fingernails and should facilitate non-invasive biomonitoring of PAHs in humans, particularly when analyzing large numbers of samples.

Simultaneous determination of 11 volatile perfluorinated compound precursors in textiles using gas chromatography-triple quadrupole mass spectrometry

以甲醇为提取溶剂,超声辅助提取纺织品中的全氟化合物前体物,建立了一种气相色谱-三重四极杆质谱(GC-MS/MS)法同时测定纺织品中11种挥发性全氟化合物前体物:4种氟调聚物醇(FTOHs)、3种氟调聚丙烯酸酯(FTAs)、2种全氟辛基磺酰胺(FOSAs)和2种全氟辛基磺酰胺乙醇(FOSEs)。考察了超声提取溶剂、提取温度和提取时间对提取效率的影响,最终确定用甲醇为提取溶剂,70 ℃下超声提取60 min,目标物经VF-WAXms毛细管柱(30 m×0.25 mm×0.25 μm)程序升温分离,GC-MS/MS多反应监测(MRM)模式检测,外标法定量。实验结果表明:11种挥发性全氟化合物前体物在10~500 μg/L范围内线性关系良好,相关系数(r)均不低于0.9984;以信噪比为3计算,检出限(LOD)为0.002~0.04 mg/kg;以信噪比为10计算,定量限(LOQ)为0.006~0.1 mg/kg;不同材质纺织品中,11种挥发性全氟化合物前体物在高、中、低3个添加水平下的回收率为73.2%~117.2%,相对标准偏差(RSD)为0.1%~9.4%(n=6)。该方法前处理简单,定性、定量准确,灵敏度高,重现性好,可有效用于纺织品中11种挥发性全氟化合物前体物的同时检测。实际样品分析发现,当前全氟化合物前体物已被应用于纺织品整理当中。该方法的建立对我国纺织品中全氟化合物前体物风险物质的管控和检测标准的制定具有一定的理论和现实意义。

Spatiotemporal distribution, source apportionment and risk assessment of typical hormones and phenolic endocrine disrupting chemicals in environmental and biological samples from the mariculture areas in the Pearl River Delta, China

The present work studied the levels, distribution, potential sources, ecological and human health risks of typical hormones and phenolic endocrine disrupting chemicals (EDCs) in the mariculture areas of the Pearl River Delta (PRD), China. The environmental levels of 11 hormones (6 estrogens, 4 progestogens, and 1 androgen) and 2 phenolic EDCs were quantified in various matrices including water, sediment, cultured fish and shellfish. Ultrahigh performance liquid chromatography-triple quadrupole tandem mass spectrometry analyses showed that all the 13 target compounds were detected in biotic samples, whereas 10 were detected in water and sediment, respectively. The total concentrations ranged from 35.06–364.53 ng/L in water and 6.31–29.30 ng/g in sediment, respectively. The average contaminant levels in shellfish (Ostrea gigas, Mytilus edulis and Mimachlamys nobilis) were significantly higher than those in fish (Culter alburnus, Ephippus orbis and Ephippus orbis). Source apportionment revealed that the pollution of hormones and phenolic EDCs in PRD mariculture areas was resulted from the combination of coastal anthropogenic discharges and mariculture activities. The hazard quotient values of the contaminants were all less than 1, implying no immediate human health risk. Overall, the present study is of great significance for scientific mariculture management, land-based pollution control, ecosystem protection, and safeguarding human health.

Source identification of amphetamine-like stimulants in Spanish wastewater through enantiomeric profiling

Amphetamine (AMP), methamphetamine (MAMP) and 3,4-methylenedioxymethamphetamine (MDMA) occur in wastewater not only as a result of illicit consumption, but also, in some cases, from prescription drug use or by direct drug disposal into the sewage system. Enantiomeric profiling of these chiral drugs could give more insight into the origin of their occurrence. In this manuscript, a new analytical methodology for the enantiomeric analysis of amphetamine-like substances in wastewater has been developed. The method consists of a solid-phase extraction (SPE) followed by liquid chromatography-triple quadrupole-tandem mass spectrometry (LC-MS/MS), which showed low quantification limits in the 2.4–5.5 ng L−1 range. The LC-MS/MS method was first applied to characterize a total of 38 solid street drug samples anonymously provided by consumers. The results of these analysis showed that AMP and MDMA trafficked into Spain are synthesized as racemate, while MAMP is exclusively produced as the S(+)-enantiomer. Then, the analytical method was employed to analyse urban wastewater samples collected from the wastewater treatment plants (WWTPs) of five different cities in 2018 and 2019. Consumption estimated through normalized population loads in wastewater showed an increased pattern of AMP use in the Basque Country. Furthermore, the enantiomeric profiling of wastewater samples was contrasted to lisdexamfetamine (LIS) and selegiline (SEL) prescription figures, two pharmaceuticals which metabolize to S(+)-AMP, and to R(-)-AMP and R(-)-MAMP, respectively. From this analysis, and considering uncertainties derived from metabolism and adherence to treatment, it was concluded that LIS is a relevant source of AMP in those cases with low wastewater loads, i.e. up to a maximum of 60% of AMP detected in wastewater in some samples could originate from LIS prescription, while SEL does not represent a significant source of AMP nor MAMP. Finally, removal efficiencies could be evaluated for the WWTP (serving ca. 860,000 inhabitants) with higher AMP influent concentrations. The removal of AMP was satisfactory with rates higher than 99%, whereas MDMA showed an average removal of approximately 60%, accompanied by an enrichment of R(-)-MDMA.