An Advanced Gas Chromatography–Mass Spectrometry Workflow for High-Confidence Non-Targeted Screening of Non-Intentionally Added Substances in Recycled Plastics

The global manufacturing of clothing is usually composed of multistep processes, which include a large number of chemicals. However, there is generally no information regarding the chemical content remaining in the finished clothes. Clothes in close and prolonged skin contact may thus be a significant source of daily human exposure to hazardous compounds depending on their ability to migrate from the textiles and be absorbed by the skin. In the present study, twenty-four imported garments on the Swedish market were investigated with respect to their content of organic compounds, using a screening workflow. Reversed-phase liquid chromatography coupled to electrospray ionization/high-resolution mass spectrometry was used for both suspect and non-target screening. The most frequently detected compound was benzothiazole followed by quinoline. Nitroanilines with suspected mutagenic and possible skin sensitization properties, and quinoline, a carcinogenic compound, were among the compounds occurring at the highest concentrations. In some garments, the level of quinoline was estimated to be close to or higher than 50,000 ng/g, the limit set by the REACH regulation. Other detected compounds were acridine, benzotriazoles, benzothiazoles, phthalates, nitrophenols, and organophosphates. Several of the identified compounds have logP and molecular weight values enabling skin uptake. This pilot study indicates which chemicals and compound classes should be prioritized for future quantitative surveys and control of the chemical content in clothing as well as research on skin transfer, skin absorption, and systemic exposure. The results also show that the current control and prevention from chemicals in imported garments on the Swedish market is insufficient.Graphical abstract

Suspect and non-target screening workflows to investigate the in vitro and in vivo metabolism of the synthetic cannabinoid 5-Cl-THJ-018

Biodegradable polyester mulch films are a viable alternative for use in agriculture to polyolefin-based films, offering reduced long-term microplastic pollution in agroecosytems with comparable protections for food security. However, these films carry diverse organic additives and non-intentionally added substances (NIASs), representing an underexplored source of anthropogenic chemicals in agroecosystems. Comprehensive chemical characterisation of these films is critical but hindered by restrictions on revealing proprietary formulations. This study presents a non-targeted screening (NTS) workflow employing multiple complementary analytical techniques to elucidate the organic composition of a polylactic acid (PLA)/polybutylene adipate-co-terephthalate (PBAT) mulch film. 1H nuclear magnetic resonance (NMR) quantified polyester contributions to the blend and revealed an unreported polybutylene sebacate (PBSe) component, likely from polybutylene sebacate terephthalate (PBSeT). Dissolution-precipitation extraction of the film followed by gas chromatography–mass spectrometry (GC-MS) and GC-flame ionisation detection (GC-FID) identified key additives in the extracted soluble fraction, including acetyl tributyl citrate (ATBC) plasticiser (4210 ± 135 μg g−1), and 8 cyclic oligoesters up to dimers. High-performance liquid chromatography-Orbitrap-mass spectrometry (HPLC-Orbitrap-MS) and direct infusion (DI)-Orbitrap-MS expanded oligoester detection to 83 additional components beyond the analytical window of GC-MS. The detailed oligoester profiles underscore the need to apply this workflow to biodegradable mulch films from diverse commercial sources and food industry applications to assess their broader chemical variability. These methodologies offer critical tools for the life cycle assessment of biodegradable agricultural plastic mulch films, advancing our understanding of the environmental impact and safety of these new materials.

Recycled textiles are becoming widely available to consumersasmanufacturers adopt circular economy principles to reduce the negativeimpact of garment production. Still, the quality of the source materialdirectly impacts the final product, where the presence of harmfulchemicals is of utmost concern. Here, we develop a risk-based suspectand non-targeted screening workflow for the detection, identification,and prioritization of the chemicals present in consumer-based recycledtextile products after manufacture and transport. We apply the workflowto characterize 13 recycled textile products from major retail outletsin Sweden. Samples were extracted and analyzed by liquid chromatographycoupled with high-resolution mass spectrometry (LC-HRMS). In positiveand negative ionization mode, 20,119 LC-HRMS features were detected and screened against persistent,mobile, and toxic (PMT) as well as other textile-related chemicals.Six substances were matched with PMT substances that are regulatedin the European Union (EU) with a Level 2/3 confidence. Forty-threesubstances were confidently matched with textile-related chemicalsreported for use in Sweden. For estimating the relative priority score,aquatic toxicity and concentrations were predicted for 7416 featureswith tandem mass spectra (MS2) and used to rank the non-targetedfeatures. The top 10 substances were evaluated due to elevated environmentalrisk linked to the recycling process and potential release at end-of-life.

Suspected-target pesticide screening using gas chromatography–quadrupole time-of-flight mass spectrometry with high resolution deconvolution and retention index/mass spectrum library

Target screening, suspects screening and non-target screening as well as “Known Unknowns” and “Unknown Unknowns” are new keywords that are currently increasing in interest in environmental (mainly water [1]) analysis. The search for unknown or expected molecules in the matrix water and others brought about new instrumental technologies and analytical strategies. A great share is based on liquid chromatography separation (LC) with atmospheric pressure ionization (API)-coupled mass spectrometric detection (MS) and is technologically very mature. Trace organic compounds are widely detected in drinking waters, surface waters and wastewater effluents. The presence of these compounds (pharmaceuticals, personal care products, pesticides, herbicides, industrial chemicals (e.g. REACH), etc.) and their transformation products as well as metabolites leads to emerging concerns about possible adverse effects on the aquatic environment and human health. The same is true for molecules in the environmental matrix air and soil. Thus the special workflows for water analysis [2] become more applicable for the environmental compartments air and soil. An overview will be given regarding new screening workflows and data work out strategies.

Liquid chromatography (LC) or gas chromatography (GC) coupled to high-resolution mass spectrometry (HRMS) is a versatile analytical method for the analysis of thousands of chemical pollutants that can be found in environmental and biological samples. While the tools for handling such complex datasets have improved, there are still no fully automated workflows for targeted screening analysis. Here we present an R-based workflow that is able to cope with challenging data like noisy ion chromatograms, retention time shifts, and multiple peak patterns. The workflow can be applied to batches of HRMS data recorded after GC with electron ionization (GC-EI) and LC coupled to electrospray ionization in both negative and positive mode (LC-ESIneg/LC-ESIpos) to perform peak annotation and quantitation fully unsupervised. We used Orbitrap HRMS data of surface water extracts to compare the Automated Target Screening (ATS) workflow with data evaluations performed with the vendor software TraceFinder and the established semi-automated analysis workflow in the MZmine software. The ATS approach increased the overall evaluation performance of the peak annotation compared to the established MZmine module without the need for any post-hoc corrections. The overall accuracy increased from 0.80 to 0.86 (LC-ESIpos), from 0.77 to 0.83 (LC-ESIneg), and from 0.67 to 0.76 (GC-EI). The mean average percentage errors for quantification of ATS were around 30% compared to the manual quantification with TraceFinder. The ATS workflow enables time-efficient analysis of GC- and LC-HRMS data and accelerates and improves the applicability of target screening in studies with a large number of analytes and sample sizes without the need for manual intervention.Graphical

The field of high-resolution mass spectrometry has undergone a rapid progress in the last years due to instrumental improvements leading to a higher sensitivity and selectivity of instruments. A variety of qualitative screening approaches, summarized as nontarget screening, have been introduced and have successfully extended the environmental monitoring of organic micropollutants. Several automated data processing workflows have been developed to handle the immense amount of data that are recorded in short time frames by these methods. Most data processing workflows include similar steps, but underlying algorithms and implementation of different processing steps vary. In this study the consistency of data processing with different software tools was investigated. For this purpose, the same raw data files were processed with the software packages MZmine2, enviMass, Compound Discoverer, and XCMS online and resulting feature lists were compared. Results show a low coherence between different processing tools, as overlap of features between all four programs was around 10%, and for each software between 40% and 55% of features did not match with any other program. The implementation of replicate and blank filter was identified as one of the sources of observed divergences. However, there is a need for a better understanding and user instructions on the influence of different algorithms and settings on feature extraction and following filtering steps. In future studies it would be of interest to investigate how final data interpretation is influenced by different processing software. With this work we want to encourage more awareness on data processing as a crucial step in the workflow of nontarget screening.

Organic aerosols make up to 70-90% of the total aerosol mass, yet ice-core studies have predominantly focused on a limited set of compounds or bulk fractions altogether. Previous investigations have centered on biomass burning tracers, marine phytoplankton oxidation products, low molecular weight carboxylic acids and persistent organic pollutants, leaving a large majority of molecules unidentified. Advances in high-resolution mass spectrometry (HRMS) have recently enabled the exploration of a wider chemical space through the development of non-target screening (NTS) workflows.In this work, we present three applications of a novel NTS method. Designed to detect secondary organic aerosol compounds in ice-core and snow samples, the method has contributed to a more comprehensive characterization of past molecular aerosol composition and has supported the development of new molecular proxies. Initially, the method was applied to the Belukha ice core (Siberian Altai, 4072 m. a.s.l.) between 1830 and 1980 CE, providing the first NTS ice-core record that embraces both the pre-industrial and industrial periods. More than 400 compounds were identified, and a clear anthropogenic fingerprint was recognized over the industrial period. Subsequently, the ice core samples from Colle Gnifetti (Switzerland, 4500 m. a.s.l.) covering the period from 1750 to 2000 CE were analyzed. Here, a smaller number of molecules was detected (≈200), consistent with the lower concentrations of dissolved organic carbon observed at this site. In both cores, most of the molecules are composed of carbon (C), hydrogen (H) and oxygen (O) and are associated with atmospheric oxidation of monoterpenes and isoprenes (e.g., succinic acid, pinic acid, azelaic acid). The industrial onset was characterized by an increase in nitrogen and sulfur containing compounds, likely due to the atmospheric reactions with anthropogenic NOx and  SO2. The higher occurrence of compounds with higher O/C ratios during the industrial period observed at both locations, suggests an increase in the atmosphere oxidative capacity. Lastly, the method was applied to 56 snow samples collected in springtime close to Ny-Ålesund (Svalbard Archipelago) and covering both pre- and phytoplankton bloom periods. Together with marine observations of algal bloom, the NTS results suggest promising evidence towards new ice-core marine productivity proxies for long-term reconstructions.

The use of synthetic cannabinoids causes similar effects as Δ9 -tetrahydrocannabinol and long-term (ab)use can lead to health hazards and fatal intoxications. As most investigated synthetic cannabinoids undergo extensive biotransformation, almost no parent compound can be detected in urine, which hampers forensic investigations. Limited information about the biotransformation products of new synthetic cannabinoids makes the detection of these drugs in various biological matrices challenging. This study aimed to identify the main in vitro biotransformation pathways of 5Cl-THJ-018 and to compare these findings with an authentic urine sample of a 5Cl-THJ-018 user. The synthetic cannabinoid was incubated with pooled human liver microsomes and cytosol to simulate phase I and phase II biotransformations. Resulting extracts were analyzed with liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Three different data analysis workflows were applied to identify biotransformation products. A suspect screening workflow used an in-house database built from literature data and in silico biotransformation predictions. Two non-target screening workflows used a commercially available software and an open-source software for mass spectrometry data processing. A total of 23 in vitro biotransformation products were identified, with hydroxylation, oxidative dechlorination, and dihydrodiol formation pathways as the main phase I reactions. Additionally, five glucuronidated and three sulfated phase II conjugates were identified. The predominant in vivo pathway was through oxidative dechlorination and in total six metabolites of 5Cl-THJ-018 were identified. Biotransformation products both in vitro and in vivo were successfully identified using complementary suspect and non-target screening workflows.

Suspect and non-target screening workflow for studying the occurrence, fate, and environmental risk of contaminants in wastewater using data-independent acquisition

Identifying and prioritizing organic toxicants in treated flowback and produced water from shale gas exploitation sites using an integrative effect-directed analysis and nontarget screening method.

Organic aerosols constitute up to 90% of submicron aerosol mass, playing a crucial role in influencing the Earth’s radiative forcing by absorbing and scattering incoming solar radiation, as well as acting as cloud condensation nuclei. To unravel the complexity of organic aerosol (OA) chemical composition, recent analytical advances, such as high-resolution mass spectrometry and the development of non-target screening (NTS) workflows, have been applied to present-day atmospheric aerosol samples. However, for a better understanding on how human activities have influenced OA chemistry, it is essential to unravel its changes between the pre-industrial and industrial periods.In this study, we present the first application of a novel NTS method to an ice core from the Belukha glacier (Russian Federation), covering the period from 1800 to 1980 CE. A total of 398 molecules were identified, mainly secondary organic aerosol tracers (SOA), such as mono- and di-carboxylic acids. Since the 1950s, we observed a shift in the atmospheric aerosol composition, characterized by the appearance of organic molecules—such as nitrogen-containing compounds—that result from increased atmospheric reactions with anthropogenic NOx or direct emissions. Additionally, we recorded a significant increase in the oxygen-to-carbon ratio (+3%) and the average carbon oxidation state (+18%) of the detected compounds compared to the pre-industrial period, suggesting an increased oxidative capacity of the atmosphere, associated with enhanced tropospheric ozone concentrations.This work demonstrates the potential of NTS ice-core studies for extending the reconstruction of OA chemical composition prior to the advent of direct instrumental monitoring, providing valuable contributions to the atmospheric aerosol community. 

Silicone wristbands have emerged as valuable passive samplers for monitoring of personal exposure to environmental contaminants in the rapidly developing field of exposomics. Once deployed, silicone wristbands collect and hold a wealth of chemical information that can be interrogated using high-resolution mass spectrometry (HRMS) to provide a broad coverage of chemical mixtures. Gas chromatography coupled to Orbitrap™ mass spectrometry (GC/Orbitrap™ MS) was used to simultaneously perform suspect screening (using in-house database) and unknown screening (using vendor databases) of extracts from wristbands worn by volunteers. The goal of this study was to optimize a workflow that allows detection of low levels of priority pollutants, with high reliability. In this regard, a data processing workflow for GC/Orbitrap™ MS was developed using a mixture of 123 environmentally relevant standards consisting of pesticides, flame retardants, organophosphate esters, and polycyclic aromatic hydrocarbons as test compounds. The optimized unknown screening workflow using a search index threshold of 750 resulted in positive identification of 70 analytes in validation samples, and a reduction in the number of false positives by over 50%. An average of 26 compounds with high confidence identification, 7 level 1 compounds and 19 level 2 compounds, were observed in worn wristbands. The data were further analyzed via suspect screening and retrospective suspect screening to identify an additional 36 compounds. This study provides three important findings: (1) a clear evidence of the importance of sample cleanup in addressing complex sample matrices for unknown analysis, (2) a valuable workflow for the identification of unknown contaminants in silicone wristband samplers using electron ionization HRMS data, and (3) a novel application of GC/Orbitrap™ MS for the unknown analysis of organic contaminants that can be used in exposomics studies.

The rate of decline in regulated persistent organic pollutant (POP) concentrations in Baltic Sea biota has leveled off in recent years, with new contaminants frequently being discovered. There is, therefore, a need for comprehensive approaches to study occurrence and temporal trends of a wide range of environmental contaminants, including legacy POPs, contaminants of emerging concern (CECs), and new contaminants. In the current work, non-target screening (NTS) workflows were developed and used for, to the best of our knowledge, the first time-trend directed NTS of biota using gas chromatography–high-resolution mass spectrometry (GC-HRMS). To maximize contaminant coverage, both electron ionization (EI) and electron capture negative ion chemical ionization (ECNI) were used. The EI data were treated using highly automated workflows to find, prioritize, and tentatively identify contaminants with statistically significant temporal trends. The ECNI data were manually processed and reviewed prior to time-trend analysis. Altogether, more than 300 tentatively identified contaminants were found to have significant temporal trends in samples of Baltic guillemot, harbor porpoise, or white-tailed sea eagle. Significant decreases were found for many regulated chemicals, as could be expected, such as PCBs, polychlorinated terphenyls, chlorobenzenes, toxaphenes, DDT, other organochlorine pesticides, and tri- and tetra- bromodiphenyl ethers (BDEs). The rate of decline of legacy POPs agreed well with data reported from targeted analyses. Significant increases were observed for small polycyclic aromatic hydrocarbons, heptaBDEs, CECs, and terpenes and related compounds. The CECs included, among others, one plasticizer tributyl acetylcitrate (ATBC), two antioxidants 2,6-bis(1,1-dimethylethyl)phenol and 2,6-bis(tert-butyl)-4-(4-morpholinyl-methyl)phenol, and two compounds used in polymer production, trimethyl isocyanurate and 2-mercaptobenzothiazole, which had not previously been reported in biota. Their increased concentrations in biota indicate increased use and release. The increase in ATBC may be linked to increased use of it as a substitute for di-2-ethylhexyl phthalate (DEHP), which has been phased out over the last decade.