High-resolution Gas Chromatography Research Articles

Co-Combustion Characteristics of Municipal Sewage Sludge and Coal in a Lab-Scale Fluidized Bed Furnace

The co-combustion of dry coal and sludge was carried out in a self-built laboratory scale fluidized bed furnace. We used FTIR spectroscopy, high-resolution gas chromatography, high-resolution mass spectrometry, and XRF to capture and dynamically observe the flue gas fly ash and bottom ash. The sludge sample was taken from a municipal sewage treatment plant and its mixing ratio was below 20%. The temperature distribution of the furnace was observed and the emissions of the main gaseous pollutants such as SO2, NOx, and dioxins were measured in the combustion process. The heavy metal contents of fly ash and bottom ash were later detected to analyze the migration characteristics. The results showed that all of the gaseous pollutants measured increased linearly with the sludge mixing ratio. However, it could also meet the 1 metal content of bottom ash and fly ash did not change much. Through the elaboration of the above points, this study can provide guidance for future research on the co-combustion of coal boiler sludge and suggest favorable conditions for the co-combustion of coal boiler sludge.

The use of gas chromatography – high resolution mass spectrometry for suspect screening and non-targeted analysis of per- and polyfluoroalkyl substances

This study is a workflow development for the analysis, identification, and categorization of per- and polyfluoroalkyl substances (PFAS) using gas chromatography-high resolution mass spectrometry (GC-HRMS) with non-targeted analysis (NTA) and suspect screening techniques. The behavior of various PFAS in a GC-HRMS was studied with regards to retention indices, ionization susceptibility, fragmentation patterns, etc. A custom PFAS database was constructed from 141 diverse PFAS. The database contains mass spectra from electron ionization (EI) mode, as well as MS and MS/MS spectra from positive and negative chemical ionization (PCI and NCI, respectively) modes. Common fragments of PFAS were identified across a diverse set of 141 PFAS analyzed. A workflow for suspect screening of PFAS and partially fluorinated products of incomplete combustion/destruction (PICs/PIDs) was developed which utilized both the custom PFAS database and external databases. PFAS and other fluorinated compounds were identified in both a challenge sample (designed to test the identification workflow) and incineration samples suspected to contain PFAS and fluorinated PICs/PIDs. The challenge sample resulted in a 100% true positive rate (TPR) for PFAS which were present in the custom PFAS database. Several fluorinated species were tentatively identified in the incineration samples using the developed workflow.

Investigation of micropollutants in household waste fractions processed by anaerobic digestion: target analysis, suspect- and non-target screening.

Household waste represents a major source of energy, nutrients, and recyclable material. In order to exploit benefits and avoid hazards in the context of circular economy, the risk profile towards human and the environment should be assessed. Here, we investigated the presence of micropollutants by quantitative target analysis, suspect and non-target screening and evaluated changes in the chemical fingerprint upon anaerobic digestion. Extracts were analyzed by reversed phase liquid chromatography high-resolution mass spectrometry (LC-HRMS) and gas chromatography mass spectrometry (GC-MS). Thirty-one of 51 target micropollutants were detected in low ng/mL levels except for few detections at µg/mL levels. The micropollutants quantified in this study included the following: pharmaceuticals (salicylic acid, amitriptyline, carbamazepine); biocides (triclocarban, 2-phenylphenol); industrial compounds used in, e.g., paper industry (pentachlorphenol, PFOS, PFOA, bisphenol A); aromatics, polycyclic aromatics, and heteroaromatics, and their alkylated, hydroxylated, or carboxylated analogues. Fifty of 206 compounds from the suspect screening list were tentatively identified. These included phthalates, methylparaben, phenol, benzophenone, and pharmaceuticals, e.g., ibuprofen. Most compounds detected by GC-MS decreased more than twofold in peak height or remained unaffected by the anaerobic digestion, and very few increased more than twofold, e.g., p-cresol, menthol, and octadecanal. From the LC-HRMS non-target screening analysis, 250 chemical components were resolved using the multiway curve resolution technique PARAFAC2; of these, carbidopa was the only identified unknown.

Unified Method for Target and Non-Target Monitoring of Pesticide Residues in Fruits and Fruit Juices by Gas Chromatography-High Resolution Mass Spectrometry.

A new polyvalent wide-scope analytical method, valid for both raw and processed (juices) fruits, combining target and non-target strategies, has been developed and validated to determine low concentrations of 260 pesticides, as well as many potential non-target substances and metabolites. The target approach has been validated according to SANTE Guide requirements. Trueness, precision, linearity, and robustness values were validated in raw fruit (apple) and juice (apple juice) as representative solid and liquid food commodities. Recoveries were between 70-120% and two ranges of linearity were observed: 0.5-20 μg kg-1 (0.5-20 μg L-1 apple juice) and 20-100 μg kg-1 (20-100 μg L-1 apple juice). The limits of quantification (LOQs) reached were lower than 0.2 μg kg-1 in apple (0.2 μg L-1 apple juice) in most cases. The developed method, based on QuEChERS extraction followed by gas chromatography-high resolution mass spectrometry (GC-HRMS), achieves part-per-trillions lower limits, which allowed the detection of 18 pesticides in commercial samples. The non-target approach is based on a retrospective analysis of suspect compounds, which has been optimized to detect up to 25 additional compounds, increasing the scope of the method. This made it possible to confirm the presence of two pesticide metabolites which were not considered in the target screening, phtamlimide and tetrahydrophthalimide.

The comparison of polymorphism among Avena species revealed by retrotransposon-based DNA markers and soluble carbohydrates in seeds

Here, we compared the polymorphism among 13 Avena species revealed by the iPBS markers and soluble carbohydrate profiles in seeds. The application of seven iPBS markers generated 83 bands, out of which 20.5% were polymorphic. No species-specific bands were scored. Shannon’s information index (I) and expected heterozygosity (He) revealed low genetic diversity, with the highest values observed for A. nuda (I = 0.099; He = 0.068). UPGMA clustering of studied Avena accessions and PCoA results showed that the polyploidy level is the main grouping criterion. High-resolution gas chromatography revealed that the studied Avena accessions share the same composition of soluble carbohydrates, but significant differences in the content of total (5.30–22.38 mg g−1 of dry weight) and particular sugars among studied samples were observed. Sucrose appeared as the most abundant sugar (mean 61.52% of total soluble carbohydrates), followed by raffinose family oligosaccharides (31.23%), myo-inositol and its galactosides (6.16%), and monosaccharides (1.09%). The pattern of interspecific variation in soluble carbohydrates, showed by PCA, was convergent to that revealed by iPBS markers. Thus, both methods appeared as a source of valuable data useful in the characterization of Avena resources or in the discussion on the evolution of this genus.

Development of a headspace-solid phase microextraction gas chromatography-high resolution mass spectrometry method for analyzing volatile organic compounds in urine: Application in breast cancer biomarker discovery

Background and aimBreast cancer (BC) is the leading cause of cancer-related death in females. The development of non-invasive methods for the early diagnosis of BC still remains challenge. Here, we aimed to discover the urinary volatile organic compounds (VOCs) pattern of BC patients and identify potential VOC biomarkers for BC diagnosis. MethodsUrine samples were analyzed by headspace-solid phase microextraction (HS-SPME) combined with gas chromatography-high resolution mass spectrometry (GC-HRMS). To assure reliable analysis, the factors influencing HS-SPME extraction efficiency were comprehensively investigated and optimized by combing the Plackett–Burman design (PBD) with the central composite design (CCD). The established HS-SPME/GC-HRMS method was validated and applied to analyze urine samples from BC patients (n = 80) and healthy controls (n = 88). ResultsA total number of 134 VOCs belonging to distinct chemical classes were identified by GC-HRMS. BC patients demonstrated unique urinary VOCs pattern. Orthogonal partial least squares-discriminant analysis (OPLS-DA) showed a clear separation between BC patients and healthy controls. Eight potential VOC biomarkers were identified using multivariate and univariate statistical analysis. The predictive ability of candidate VOC biomarkers was further investigated by the random forest (RF) algorithm. The candidate VOC biomarkers yielded 76.3% sensitivity and 85.4% specificity on the training set, and achieved 76.0% sensitivity and 92.3% specificity on the validation set. ConclusionsOverall, this work not only established a standardized HS-SPME/GC-HRMS approach for urinary VOCs analysis, but also highlighted the value of urinary VOCs for BC diagnosis. The knowledge gained from this study paves the way for early diagnosis of BC using urine in a non-invasive manner.

Simple multi-residue analysis of persistent organic pollutants and molecular tracers in atmospheric samples

We present a simple, selective and sensitive analytical method to quantitatively determine a wide range of halogenated persistent organic pollutants and molecular tracers in atmospheric samples. Identification and quantification was carried out by high-resolution gas chromatography, hyphenated with low-resolution mass spectrometry operating in electron impact (EI) and electron capture negative ionization (ECNI) mode. Optimization on a number of instrumental parameters was conducted to obtain ultra-trace detection limits, in the range of few fg/m3 for organohalogen compounds. Repeatability and reproducibility of the method was thoroughly evaluated. The analysis was validated with standard reference materials and successfully applied to actual atmospheric samples. The proposed multi-residue method provides a precise, affordable and practical procedure of sample analysis for environmental research laboratories with conventional instrumentation on a routine basis.•A simple combination of alumina, florisil and silica gel adsorbents was applied to sufficiently isolate polychlorinated biphenyls, organochlorine pesticides, polycyclic aromatic hydrocarbons, long chain n-alkanes, hopanes and steranes.•Full elution was achieved in two successive fractions, using small volumes of n-hexane and n-hexane/dichloromethane to recover all target substances.•To maximize analytical response, optimization was applied for three operating parameters in ECNI mode: i) ion source temperature; ii) emission current; and iii) electron energy.

DIOXINS, FURANS AND PCBS IN IMPORTED MARINE FISH – CONSUMER EXPOSURE

Background. Dietary guidelines recommend that fish should be consumed at least twice a week due to valuable nutrients they contain, like long-chain, polyunsaturated fatty acids, macro- and microelements, fat-soluble vitamins (mainly D3), amino acids and easily digestible protein. Apart from the benefits, fish consumption becomes a source of toxic compounds including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs). The aim of our research was to investigate the levels of PCDD, PCDF and PCB in marine fish imported to Poland and assess the risk for consumers, taking into account the tolerable weekly intake (TWI) of 2 pg WHO TEQ/kg body weight (b.w.). Six fish species were investigated: turbot, mackerel, Atlantic salmon, tuna, pollock and hake. The method employed for the research was isotope dilution technique with high resolution gas chromatography coupled with high resolution mass spectrometry (HRGC-HRMS). Results and conclusions. The highest concentrations for the sum of PCDD/F/dl-PCB were determined in turbot muscles 1.25 pg WHO-TEQ/g of fresh weight (f.w.) and the lowest in pollock, hake and tuna muscles 0.02, 0.03, 0.04 pg WHO-TEQ/g f.w. respectively. Although the tested fish contained low PCDD/F/PCB concentrations compared to the permissible limits, the consumption of the recommended two portions of the most contaminated species resulted in TWI being exceeded even six times for children and two times for adults. Imported turbot, salmon and mackerel are significant sources of dioxins and PCBs for fish consumer.

Analysis of N-nitrosodimethylamine in metformin hydrochloride products by high-resolution accurate mass gas chromatography mass spectrometry.

The high resolving power of the Orbitrap mass spectrometer in a high-resolution accurate mass gas chromatography (HRAM-GC-MS) system provides greater selectivity and sensitivity for the identification and quantification of volatile analytes at low parts per billion (ppb) levels. Hence, it can be applied for the analysis of pharmaceutical impurities like N-nitrosodimethylamine (NDMA) in metformin hydrochloride products (METs). Different METs extracted by a dichloromethane/aqueous system were analyzed by HRAM-GC-MS under softer electron ionization (EI) at 30 eV. The accurate masses of NDMA and its internal standard NDMA-d6 were analyzed by full scan and targeted selected ion monitoring modes under 60 000 and 30 000 full width at half maximum at m/z 200, respectively. Data acquisition and processing were managed by Xcalibur and Trace Finder software, respectively. Limits of detection (LOD) and quantification (LOQ) at 10 and 20 ng/g were achieved, which is below the allowed daily intake of 32 ng/g. The mass errors measured from experimental data were within ±2 ppm of the theoretical values over a period of a week. Sample analysis showed that 180 out of 212 samples (85%) were below LOD and 15 out of 212 samples (7 %) were within LOD and LOQ. Only 17 samples (8%) were found to be above LOQ, comprising one active pharmaceutical ingredient (API), five immediate-release METs and 11 extended-released METs. Amongst these, seven extended-release METs and one API exceeded the daily allowed intake, 32 ng/g. The validated method has been successfully applied for NDMA analysis in various forms of METs. The method is rather straightforward without an additional clean-up step. The scope can also be extended to other volatile impurities in finished pharmaceutical products.

Fingerprinting and identification of isolated plastic polymers with pyrolysis comprehensive two-dimensional gas chromatography and flame ionization detection.

An approach using pyrolysis with comprehensive two-dimensional gas chromatography with flame ionization detection is introduced for identifying common isolated plastic polymers. A quadrupole mass spectrometer is employed as a parallel detector to aid method development and improve polymer identification in complex matrices. Common plastic polymers including polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyamide, poly(methyl methacrylate), styrene-butadiene rubber, and polyethylene terephthalate are accurately identified within a total analysis time of 45min. A strategy to enhance compatibility of high-resolution capillary gas chromatography using a 150-µm internal diameter column technology and a larger internal volume microfurnace-based pyrolyzer is discussed. This strategy resulted in minimizing the band broadening effect caused by the pyrolyzer's internal volume and overcoming the slow pressure buildup when the sample is inserted into the furnace. Prolonged pressure buildup to reach a final pressure setting can cause a safety shutdown to the pneumatic control system. The developed approach is complementary to spectroscopic techniques by offering mass based, chemical composition analysis of plastics.

Variability in metabolites produced by Talaromyces pinophilus SPJ22 cultured on different substrates

BackgroundSeveral metabolites released by fungal species are an essential source of biologically active natural substances. Gas chromatography high resolution time-of-flight mass spectrometry (GC-HRTOF-MS) is one of the techniques used in profiling the metabolites produced by microorganisms, including Talaromyces pinophilus. However, there is limited information regarding differential substrates’ impacts on this fungal strain’s metabolite profiling. This study examined the metabolite profile of T. pinophilus strain SPJ22 cultured on three different media, including solid czapek yeast extract agar (CYA), malt extract agar (MEA) and potato dextrose agar (PDA) using GC-HRTOF-MS. The mycelia including the media were plugged and dissolved in 5 different organic solvents with varying polarities viz.: acetonitrile, dichloromethane, hexane, 80% methanol and water, and extracts analysed on GC-HRTOF-MS.ResultsThe study revealed the presence of different classes of metabolites, such as fatty acids (2.13%), amides (4.26%), alkanes (34.04%), furan (2.13%), ketones (4.26%), alcohols (14.89%), aromatic compounds (6.38%), and other miscellaneous compounds (17.02%). Significant metabolites such as acetic acid, 9-octadecenamide, undecanoic acid methyl ester, hydrazine, hexadecane, nonadecane, eicosane, and other compounds reported in this study have been widely documented to have plant growth promoting, antimicrobial, anti-inflammatory, antioxidant, and biofuel properties. Furthermore, T. pinophilus grown on PDA and MEA produced more than twice as many compounds as that grown on CYA.ConclusionThus, our result showed that the production of essential metabolites from T. pinophilus is substrate dependent, with many of these metabolites known to have beneficial characteristics, and as such, this organism can be utilised as a sustainable and natural source for these useful organic molecules.

Effect of Flower Development Stages on the Dynamics of Volatile Compounds in Ylang-Ylang (Cananga odorata) Essential Oil

Several abiotic factors influence the chemical composition of essential oils. Understanding these factors is an important step in developing quality products that meet market demands. This research work aims to study the chemical composition of the essential oils of ylang-ylang (Cananga odorata, forma genuina) according to the maturity of flowers. The volatile compounds of ylang-ylang flowers from Reunion Island were extracted by hydrodistillation and the samples were analyzed by high resolution gas chromatography coupled with mass spectrometry (GC-MS) allowing for the identification of 70 volatile compounds. The chemical composition of the essential oils extracted from the flowers at 5 different stages of development varies both qualitatively and quantitatively. The volatile compounds observed belong to 4 chemical groups which are esters, alcohols, terpenes, and ether-oxides. The synthesis of light oxygenated compounds is largely the predominant chemical subgroup in all stages of development. Their relative content is considerably increased during flower ripening with a peak concentration in stage 4 (SD4). The highest concentrations of non-terpene esters and heavy oxygenated compounds are found in stages 1 (SD1) and (SD5), respectively, while no chemical subgroup is dominant in the intermediate stages 2 (SD2) and (SD3). The dynamics of volatile compounds have also been studied. This study established that the stage of development of ylang-ylang flowers significantly influences the dynamics of volatile compounds in the extracted essential oils. Total oxygenated compounds that are highly odoriferous in essential oils increase progressively and significantly with flower maturity, unlike hydrocarbon terpenes, which are less valuable in terms of their contribution to the fragrance and following opposite kinetics; suggesting that odoriferous properties increase with the development of the flower, with a higher intensity at SD4.

Associations between Maternal Polychlorinated Dibenzo-p-dioxin and Dibenzofuran Serum Concentrations and Pulse Pressure in Early Pregnancy: A Cross-Sectional Study.

Pulse pressure (PP) is the difference between systolic blood pressure (SBP) and diastolic blood pressure (DBP), and an independent predictor of cardiovascular risk. Previous research suggests, with different conclusions, that exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) could affect blood pressure (BP). We conducted a cross-sectional study to determine the association of dioxin exposure with PP in early pregnancy. A total of 305 pregnant women in early pregnancy in Yingcheng, China, recruited from May 2018 to February 2021, were included in this study. We measured 17 congeners of PCDD/Fs in maternal serum via high-resolution gas chromatography tandem high-resolution mass spectrometry. A generalized linear regression model was used to analyze the influencing factors of dioxin exposure and their relationships with PP. The levels of total PCDD/Fs (∑PCDD/Fs) ranged from 163.52 pg/g lipid to 1,513,949.52 pg/g lipid, with a mean of 10,474.22 pg/g lipid. The mean toxicity equivalent (TEQ) of total PCDD/Fs (∑TEQ-PCDD/Fs) was 42.03 pg/g lipid. The ratio of tetrachlorinated to octa-chlorinated congeners in maternal serum was enriched with an increasing number of chlorines. Pregnant women with college and above education had higher concentrations of ∑PCDD/Fs than those with education levels of junior high school and below (β = 0.34, 95% CI: 0.01, 0.67). The adjusted model for ∑TEQ-PCDD/Fs was significantly and negatively associated with PP (β = -1.79, 95% CI: -2.91, -0.68). High levels of dioxins were found in this area, and exposure to dioxins may affect the PP of women in early pregnancy, with health risks.

SPME-GC-HRTOF-MS dataset of fermented maize flour volatilome

Background: The volatilome of fermented food products are essential metabolites that significantly contribute to such foods’ overall composition and sensorial quality. The dataset presented herein represents the volatilome of raw and fermented maize flour samples. Methods: Maize grains were milled and naturally fermented at 35°C into sourdough at different periods (24, 48 and 72 h) and, at each point, the profile of the volatiles was investigated. Samples at the different fermentation periods were analyzed using solid phase microextraction coupled with a gas chromatography-high resolution time of flight-mass spectrometry (SPME-GC-HRTOF-MS). Results: Data obtained were classified into different compound groups such as alcohols, aldehydes, aromatic compounds, esters, organic acids, terpenes, ketones, among others and their characteristics such as the retention time, observed mass, molecular formular, mean peak areas and mass spectra also presented. Conclusion: These datasets of fermented maize volatilome can be used as biomarkers for maize fermentation.

Water quality monitoring based on chemometric analysis of high-resolution phytoplankton data measured with flow cytometry

River water is an important source of Dutch drinking water. For this reason, continuous monitoring of river water quality is needed. However, comprehensive chemical analyses with high-resolution gas chromatography [GC]-mass spectrometry [MS]/liquid chromatography [LC]-MS are quite tedious and time consuming; this makes them poorly fit for routine water quality monitoring and, therefore, many pollution events are missed. Phytoplankton are highly sensitive and responsive to toxicity, which makes them highly usable for effect-based water quality monitoring. Flow cytometry can measure the optical properties of phytoplankton every hour, generating a large amount of information-rich data in one year. However, this requires chemometrics, as the resulting fingerprints need to be processed into information about abnormal phytoplankton behaviour. We developed Discriminant Analysis of Multi-Aspect CYtometry (DAMACY) to model the “normal condition” of the phytoplankton community imposed by diurnal, meteorological, and other exogenous influences. DAMACY first describes the cellular variability and distribution of phytoplankton in each measurement using principal component analysis, and then aims to find subtle differences in these phytoplankton distributions that predict normal environmental conditions. Deviations from these normal environmental conditions indicated abnormal phytoplankton behaviour that happened alongside pollution events measured with the GC/MS and LC/MS systems. Thus, our results demonstrate that flow cytometry in combination with chemometrics may be used for an automated hourly assessment of river water quality and as a near real-time early warning for detecting harmful known or unknown contaminants. Finally, both the flow cytometer and the DAMACY algorithm run completely autonomous and only requires maintenance once or twice per year. The warning system results may be uploaded automatically, so that drinking water companies may temporary stop pumping water whenever abnormal phytoplankton behaviour is detected. In the case of prolonged abnormal phytoplankton behaviour, comprehensive analysis may still be used to identify the chemical compound, its origin, and toxicity.

Distribution and bioaccumulation of polychlorinated dibenzo-p-dioxins and dibenzofurans in the tissues of Yorkshire pig.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in various foods continuously concern the public. Pork and its byproducts, especially from Yorkshire pigs, are the largest meat food consumed by the general population in China. This study aims to investigate the distribution of PCDD/Fs in different tissues of Yorkshire pigs to understand their bioaccumulation. Yorkshire pigs were fed a known amount of PCDD/Fs through fly ash. PCDD/Fs were determined by isotope dilution method with a gas chromatography-high resolution mass spectrometer. The liver had the highest concentration levels (2041.33 pg/g lipid) and toxic equivalents values (69.14 pg/g lipid), followed by the spleen and lung, and the lowest ones in the brain. The liver also had the highest bioaccumulation of PCDD/Fs, and this level was considerably higher than that of other tissues. This study showed a strong accumulation capacity of the liver for polychlorinated dibenzo-p-dioxins and dibenzofurans under short-term exposure conditions, suggesting that the liver is a more sensitive tissue for monitoring PCDD/Fs in food safety risk monitoring. PRACTICAL APPLICATION: This paper may help the consumer in making food choices to minimize the exposure risk to Polychlorinated dibenzo-p-dioxins and dibenzofurans.

Determination of polychlorinated dibenzo-p-dioxins and furans in food samples by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) and comparison with gas chromatography-high resolution mass spectrometry (GC-HRMS)

Although gas chromatography–triple quadrupole mass spectrometry (GC-MS/MS) has been applied to the determination of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in various food samples, there is insufficient evidence to evaluate its equivalence with gas chromatography–high resolution mass spectrometry (HRMS). In the present study, two GC-MS/MS instruments with different ion sources (advanced electron ionization [EI] and atmospheric pressure chemical ionization [APCI]) were evaluated for detecting trace levels of PCDD/Fs in various foods. GC-EI-MS/MS and GC-APCI-MS/MS showed good linear relationships for 17 PCDD/Fs (0.01–200 ng/mL, R2 > 0.999), and the relative standard deviations of the relative response factors were 3–18%. The limit of quantitation range of the PCDD/Fs was 0.005–0.101 ng/mL with GC-APCI-MS/MS and 0.006–0.201 ng/mL with GC-EI-MS/MS. The capabilities of the GC-MS/MS methods were evaluated for determination of PCDD/Fs in reference materials and real food samples. Statistical analyses showed that the toxic equivalents (TEQs) were comparable to those obtained with GC-HRMS, and the methods had good sensitivity, repeatability, and reproducibility. No difference was found between the results from the GC-MS/MS techniques and GC-HRMS when the PCDD/Fs concentrations were greater than 10−2 pg/g. The results suggest that when the total TEQ is greater than 0.57 pg TEQ/g (lipid weight) or 0.052 pg TEQ/g (wet weight), GC-MS/MS techniques could be used as a complementary approach to GC-HRMS. Both GC-EI-MS/MS and GC-APCI-MS/MS have similar sensitivity, selectivity, and stability to HRMS and could be used as confirmation methods for the analysis of trace PCDD/Fs in animal foods.

Novel biomonitoring method for determining five classes of legacy and alternative flame retardants in human serum samples

Flame retardants (FRs) are ubiquitous in environment and biota and may pose harm to human health. In recent years, concern regarding legacy and alternative FRs has been intensified due to their widespread production and increasing contamination in environmental and human matrices. In this study, we developed and validated a novel analytical method for simultaneous determination of legacy and alternative FRs, including polychlorinated naphthalenes (PCNs), short- and middle-chain chlorinated paraffins (SCCPs and MCCPs), novel brominated flame retardants (NBFRs), and organophosphate esters (OPEs) in human serum. Serum samples were prepared by liquid-liquid extraction using ethyl acetate, and purified with Oasis® HLB cartridge and Florisil–silica gel columns. Instrumental analyses were carried out using gas chromatography-triple quadrupole mass spectrometry, high-resolution gas chromatography coupled with high-resolution mass spectrometry, and gas chromatography coupled with quadrupole time-of-flight mass spectrometry, respectively. The proposed method was validated for linearity, sensitivity, precision, accuracy, and matrix effects. Method detection limits for NBFRs, OPEs, PCNs, SCCPs, and MCCPs were 4.6 × 10–4–8.6 × 10–2, 4.3 × 10–3–1.3, 1.1 × 10–5–1.0 × 10–4, 1.5, and 9.0 × 10–1 ng/mL, respectively. Matrix spike recoveries ranged from 73%–122%, 71%–124%, 75%–129%, 92%–126%, and 94%–126% for NBFRs, OPEs, PCNs, SCCPs, and MCCPs, respectively. The analytical method was applied for detection of real human serum. CPs were the dominant FRs in serum, indicating CPs were widely presented in human serum and should be pay more attention for their health risk.

Legacy and novel brominated flame retardants in air of Ny-Ålesund, Arctic from 2011 to 2019

Concentrations of polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (NBFRs) in the atmosphere of Ny-Ålesund, Svalbard, were investigated. Passive air samples were collected for eight consecutive one-year periods from August 2011 to August 2019 at seven Arctic sampling sites. High-resolution gas chromatography coupled with high-resolution mass spectrometry (HRGC-HRMS) and gas chromatography coupled with election capture negative ionization mass spectrometry (GC-NCI-MS) were employed for PBDE and NBFR analysis, respectively. The median concentrations of Ʃ11PBDEs and Ʃ6NBFRs were 0.6 pg/m3 and 4.0 pg/m3, respectively. Hexabromobenzene and BDE-47 were the most abundant NBFR and PBDE congeners in the atmosphere, accounting for 31% and 24% of ƩNBFR and ƩPBDE concentrations, respectively. ƩNBFR concentration was approximately six times higher than that of ƩPBDEs in the same samples. Among NBFRs, the concentrations of 1,2,3,4,5-pentabromobenzene, 2,3,4,5,6-pentabromobenzene, and 2,3-dibromopropyl-2,4,6-tribromophenyl ether showed increasing temporal variations, with estimated doubling times of 3.0, 3.3, and 2.8 years, respectively. The concentrations of almost all PBDE congeners showed a decreasing variation, with halving times ranging from 2.1 to 9.5 years.

Gas chromatography-triple quadrupole mass spectrometry as a cost-effective method for the determination of polychlorinated dibenzo–p-dioxins and furans in contaminated soils

The aim of this study was to evaluate the performance of gas chromatography (GC)-triple quadrupole mass spectrometry (QqQ, MS/MS) as an alternative to the standard GC-high resolution mass spectrometry (GC-HR/MS) for soils contaminated with polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). GC-QqQ (MS/MS) using a dynamic multiple reaction monitoring (dMRM) mode was optimized for the quantitative analysis of 17 PCDD/Fs. A comparative study between GC-QqQ (MS/MS) and GC-HR/MS was carried out to validate the results of actual field soil samples. Although GC-HR/MS has excellent sensitivity and selectivity, the validation parameters obtained by GC-QqQ (MS/MS) also met the recommended criteria of the standard method. The results for total and I-TEQ (international toxic equivalent) value of the PCDD/F concentrations of over 86.0 pg/g and 4.3 pg I-TEQ/g, respectively, in actual field soil samples showed good agreement between the two methods, falling within ±25% relative difference. In consideration of the remediation goal (100 pg I-TEQ/g), GC-QqQ (MS/MS) can be an alternative cost-effective method for use in soil remediation research.