Interspecies comparison of metabolism of two novel prototype PFAS.

As a result of proposed global restrictions and regulations on current-use per-and polyfluoroalkyl substances (PFAS), research on possible alternatives is highly required. In this study, phase I in vitro metabolism of two novel prototype PFAS in human and rat was investigated. These prototype chemicals are intended to be safer-by-design and expected to mineralize completely, and thus be less persistent in the environment compared to the PFAS available on the market. Following incubation with rat liver S9 (RL-S9) fractions, two main metabolites per initial substance were produced, namely an alcohol and a short-chain carboxylic acid. While with human liver S9 (HL-S9) fractions, only the short-chain carboxylic acid was detected. Beyond these major metabolites, two and five additional metabolites were identified at very low levels by non-targeted screening for the ether- and thioether-linked prototype chemicals, respectively. Overall, complete mineralization during the in vitro hepatic metabolism of these novel PFAS by HL-S9 and RL-S9 fractions was not observed. The reaction kinetics of the surfactants was determined by using the metabolite formation, rather than the substrate depletion approach. With rat liver enzymes, the formation rates of primary metabolite alcohols were at least two orders of magnitude higher than those of secondary metabolite carboxylic acids. When incubating with human liver enzymes, the formation rates of single metabolite carboxylic acids, were similar or smaller than those experienced in rat. It also indicates that the overall metabolic rate and clearance of surfactants are significantly higher in rat liver than in human liver. The maximum formation rate of the thioether congener exceeded 10-fold that of the ether in humans but were similar in rats. Overall, the results suggest that metabolism of the prototype chemicals followed a similar trend to those reported in studies of fluorotelomer alcohols.

Finding a way out? Comprehensive biotransformation study of novel fluorinated surfactants.

In this study the environmental fate of two novel trifluoromethoxy-substituted surfactants with respectively an ether or thioether linkage were investigated, of which the design aimed for less persistency and complete mineralization. Long-term microbial transformation studies under aerobic conditions in activated sludge-wastewater medium were performed for 126 days. A semi-closed experimental system with a trapping sorbent was selected to avoid losses of possible volatile transformation products (TPs). The changes in the concentration of the surfactants and their expected TPs were monitored by target analysis using liquid chromatography-tandem mass spectrometry. Significant decrease in the concentration of the surfactants was observed over the incubation period. The main detected TPs were short-chained carboxylic acids (CAs), including a CA with two fluorinated carbon atoms representing the last product prior to mineralization. High stability of these CAs and lack in the formation of inorganic fluoride over the incubation time was however observed. Consequently, unequivocal final mineralization of the investigated surfactants could not be confirmed. Regarding the mass balance, the total amount of detected substances achieved only 30-37% of the expected concentration at the end of the incubation time. The reason of the incomplete mass balance should be further investigated.

Efficacy of activated carbon filtration and ozonation to remove persistent and mobile substances - A case study in two wastewater treatment plants.

Persistent and mobile (PM) substances are able to spread quickly in the water cycle and were thus identified as potentially problematic for the environment and water quality. If also toxic (PMT) or very persistent and very mobile (vPvM) their regulation under REACH as substances of very high concern is foreseen. Yet, knowledge on the effectiveness of advanced wastewater treatment in removing PM-substances from WWTP effluents is limited to few rather well-known chemicals. The occurrence and behavior of 111 suspected and known PM-substances was investigated in two wastewater treatment plants employing either powdered activated carbon (PAC, full-scale) or ozonation with subsequent sand/anthracite filtration (pilot-scale) and an additional granular activated carbon (GAC) filtration was investigated. 72 of the 111 PM-substances analyzed were detected at least once in the secondary effluent of either wastewater treatment plant, resulting in total concentrations of 104 µg/L and 40 µg/L, respectively. While PAC removed 32 % of PM-substances well, the total PM burden in the effluent was only reduced from 103 µg/L to 87 µg/L. Ozonation and the subsequent sand/anthracite filtration was able to reduce the PM burden in wastewater from 40 µg/L to 19 µg/L, showing a higher removal efficacy than PAC in this study. The additional GAC filtration further reduced the total PM-concentration to 13 µg/L. Among the investigated PM-chemicals detected were constituents of ionic liquids: The anion hexafluorophosphate was one of few chemicals that was detected in effluent concentrations >1 µg/L and could not be removed by the processes studied, showing that for some chemicals preventive actions may be required.

Narrowing the analytical gap for water-soluble polymers: A novel trace-analytical method and first quantitative occurrence data for polyethylene oxide in surface and wastewater.

Water-soluble polymers (WSPs) like polyethylene oxide (PEO) have annual production volumes ranging from thousands to millions of tonnes and are used in a wide variety of applications that enable a release into the aquatic environment. Despite these facts, a lack of quantitative trace-analytical methods for WSPs prevents the comprehensive study of their environmental occurrence. Here, size exclusion chromatography was hyphenated with electrospray ionization high-resolution mass spectrometry. An all-ion fragmentation approach for the formation of diagnostic fragments independent of molecular weight, charge state, and ion species was used to quantify PEO and its derivatives in wastewater treatment plants (WWTPs) and surface water samples. Despite its inherent biodegradability, PEO concentrations found in the samples analysed ranged from 1 µg/L) and reached up to 20 µg/L (effluent) and 400 µg/L (influent) for WWTPs. A substantial shift in molecular weight ranges was observed between influent and effluent, pointing towards a molecular weight fraction between 1.3 and 4 kDa being dominant in the effluent. Due to an assumed size exclusion during sample enrichment, information on the MW-distribution of PEO is limited to MW < 55 kDa. The high concentrations widely detected for a readily biodegradable WSP such as PEO, raise strong concerns about the occurrence and fate of recalcitrant WSPs in the aquatic environment. The method presented herein may provide the tools necessary to assess the burden of these high production volume chemicals and the risk they may pose.

Unraveling the dynamics of organic micropollutants in wastewater: Online LC-MS/MS analysis at high temporal resolution.

Online monitoring of organic micropollutants (OMPs) in the aquatic environment at high temporal resolution is an upcoming technique that provides insights into their dynamics and has the potential to bring water research and management to a new level. An online monitoring setup was developed to quantify OMPs in wastewater treatment plant (WWTP) influent and effluent using automated and continuous sampling, sample preparation, online solid-phase extraction-liquid chromatography-tandem mass spectrometry analysis and data evaluation. This online monitoring setup provided high selectivity and sensitivity (limit of quantification down to 1 ng/L) as well as a stable performance during one week of constant operation whilst using a high sampling frequency of 10 min (>1000 samples). Custom automated data evaluation enabled quantification within seconds after each measurement and results were comparable to those from a commercial software. Additionally, an alarm tool was included in the evaluation application, which automatically notified the user in case a substance exceeded a predefined threshold. The online monitoring setup was applied to WWTP influent and effluent, where 57 substances were monitored over a period of one week and two days, respectively. High temporal resolution enabled the observation of periodic patterns of pharmaceuticals as well as pollution by OMPs originating from point and diffuse sources, while dynamics of OMPs in WWTP effluent were less pronounced. These new insights into the dynamics of OMPs in WWTP influent, which would not be observable using 24 h composite samples, will be a starting point for new stormwater and wastewater research and management strategies.

Biomarker responses in zebrafish (Danio rerio) following long-term exposure to microplastic-associated chlorpyrifos and benzo(k)fluoranthene.

Continuously increasing plastic production causes a constant accumulation of microplastic particles (MPs) in the aquatic environment, especially in industrialized and urbanized areas with elevated wastewater discharges. This coincides with the release of persistent organic pollutants (polycyclic aromatic hydrocarbons (PAHs), pesticides) entering limnic ecosystems. Although the assessment of potential effects of environmental pollutants sorbed to MPs under chronic exposure scenarios seems vital, data on potential hazards and risk by combined exposure to pollutants and microplastics for aquatic vertebrates is still limited. Therefore, zebrafish (Danio rerio) were exposed over 21 days to the organophosphate insecticide chlorpyrifos (CPF; 10 and 100 ng/L) and the PAH benzo(k)fluoranthene (BkF; 0.78 and 50 µg/L) either dissolved directly in water or sorbed to different MPs (irregular polystyrene, spherical polymethyl methacrylate; ≤ 100 µm), where CPF was sorbed to polystyrene MPs and BkF was sorbed to polymethyl methacrylate MPs. Contaminant sorption to MPs and leaching were documented using GC-EI-MS; potential accumulation was studied in cryosections of the gastrointestinal tract. Enzymatic biomarkers and biotransformation were measured in liver and brain. Overall, exposure to non-contaminated MPs did not induce any adverse effects. Results of fluorescence tracking, CYP1A modulation by BkF as well as changes in acetylcholinesterase activity (AChE) by CPF were less pronounced when contaminants were sorbed to MPs, indicating reduced bioavailability of pollutants. Overall, following exposure to waterborne BkF, only minor amounts of parent BkF and biotransformation products were detected in zebrafish liver. Even high loads of MPs and sorbed contaminants did not induce adverse effects in zebrafish; thus, the potential threat of MPs as vectors for contaminant transfer in limnic ecosystems can be considered limited.

Nontarget screening of production waste samples from Leuckart amphetamine synthesis using liquid chromatography - high-resolution mass spectrometry as a complementary method to GC-MS impurity profiling.

The established approaches of suspect and nontarget screening (NTS) using liquid chromatography-high-resolution mass spectrometry (LC-HRMS) are usually applied in the field of environmental and bioanalytical analysis. Herein, these approaches were employed on a forensic-toxicological application by analyzing different production waste samples from controlled amphetamine synthesis via Leuckart route to evaluate the suitability of this methodology for identification of route-specific organic substances in such waste samples. For analysis, two complementary LC techniques were used to cover a broad polarity spectrum. After data processing and peak picking using the enviMass software and further manual data restriction, 17 features were tentatively identified as suspects, three of which were subsequently identified with reference substances. All suspects had been previously identified in studies, in which gas chromatography-mass spectrometry (GC-MS) was successfully applied for synthesis marker assessment in waste and amphetamine samples. Remaining features with high signal intensity and assigned sum formula were selected for the attempt of structure elucidation. Seven potential synthesis markers were tentatively identified, which were not yet reported, except the sum formula of one compound, and which were partly also detected in real case waste samples afterward. The innovative application of the NTS approach using LC-HRMS for the analysis of aqueous amphetamine synthesis waste samples showed its suitability as extension to GC-MS analysis as it was possible to successfully identify seven new potential marker compounds, which are specific either for the conversion of the pre-precursors α-phenylacetoacetonitrile and α-phenylacetoacetamide to benzyl methyl ketone or for the subsequent Leuckart synthesis route after their conversion.

Probing the chemical complexity of tires: Identification of potential tire-borne water contaminants with high-resolution mass spectrometry.

Tire wear particles are not only the type of polymer particles most prevalent in the environment but also act as source of various organic micropollutants, many of which are likely still unknown. We extracted particles prepared from nine tires in artificial freshwater (28 d) with the goal to characterize leachables (max intensity >105 in artificial freshwater), which are tire-borne water contaminants. A subsequent extraction of these particles with acetone (3 h) was used to assess the long-term leaching potential. A suspect and nontarget screening in aliquots of each extract led to the detection of 214 organic substances of which 145 were classified as leachables. The intrinsic polarity of some leachables (mean log D (pH 7.4) 3.9), which facilitates an increased aquatic mobility, highlights their potential as environmental water contaminants. With N,N'-diphenylguanidine (DPG) and benzothiazole, two of the ten unequivocally identified leachables, are classified as potential persistent, mobile and toxic substance by the German Environment Agency. Of the identified chemicals DPG showed the highest intensities in aqueous extracts and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6-PPD), the precursor of 6-PPD-quinone, in acetone extracts. A comparison between the 69 detected suspects and 174 high-intensity signals (>106) detected in the nontarget screening led to an overlap of only 29 features. A detailed investigation of the remaining high-intensity suspects revealed the presence of 13 proposed DPG reaction products, further highlighting the chemical complexity of tires. Consequently, we conclude that there are many, often still unrecognized chemicals entering the aquatic environment through leaching from tire wear particles.

Rethinking the relevance of microplastics as vector for anthropogenic contaminants: Adsorption of toxicants to microplastics during exposure in a highly polluted stream - Analytical quantification and assessment of toxic effects in zebrafish (Danio rerio).

Given the increasing amounts of plastic debris entering marine and freshwater ecosystems, there is a growing demand for environmentally relevant exposure scenarios to improve the risk assessment of microplastic particles (MPs) in aquatic environments. So far, data on adverse effects in aquatic organisms induced by naturally exposed MPs are scarce and controversially discussed. As a consequence, we investigated the potential role of MPs regarding the sorption and transfer of environmental contaminants under natural conditions. For this end, a mixture of four common polymer types (polyethylene, polypropylene, polystyrene, polyvinyl chloride) was exposed to natural surface water in a polluted stream for three weeks. Samples of water, MP mixture, sediment, and suspended matter were target-screened for the presence of pollutants using GC/LC-MS, resulting in up to 94 different compounds. Possible adverse effects were investigated using several biomarkers in early developmental stages of zebrafish (Danio rerio). Exposure to natural stream water samples significantly inhibited acetylcholinesterase activity, altered CYP450 induction and modified behavioral patterns of zebrafish. In contrast, effects by samples of both non-exposed MPs and exposed MPs in zebrafish were less prominent than effects by water samples. In fact, the analytical target screening documented only few compounds sorbed to natural particles and MPs. Regarding acute toxic effects, no clear differentiation between different MPs and natural particles could be made, suggesting that - upon exposure in natural water bodies - MPs seem to approximate the sorption behavior of natural particles, presumably to a large extent due to biofilm formation. Thus, if compared to natural inorganic particles, MPs most likely do not transfer elevated amounts of environmental pollutants to biota and, therefore, do not pose a specific additional threat to aquatic organisms.

Filling the knowledge gap: A suspect screening study for 1310 potentially persistent and mobile chemicals with SFC- and HILIC-HRMS in two German river systems.

Persistent and mobile chemicals (PM chemicals) were searched for in surface waters by hydrophilic interaction liquid chromatography (HILIC) and supercritical fluid chromatography (SFC), both coupled to high resolution mass spectrometry (HRMS). A suspect screening was performed using a newly compiled list of 1310 potential PM chemicals to the data of 11 surface water samples from two river systems. In total, 64 compounds were identified by this approach. The overlap between HILIC- and SFC-HRMS was limited (31 compounds), confirming the complementarity of the two methods used. The identified PM candidates are characterized by a high polarity (median logD -0.4 at pH 7.5), a low molecular weight (median 187 g/mol), are mostly ionic (54 compounds) and contain a large number of heteroatoms (one per four carbons on average). Among the most frequently detected novel or yet scarcely investigated water contaminants were cyanoguanidine (11/11 samples), adamantan-1-amine (10/11), trifluoromethanesulfonate (9/11), 2-acrylamido-2-methylpropanesulfonate (10/11), and the inorganic anions hexafluorophosphate (11/11) and tetrafluoroborate (10/11). 31% of the identified suspects are mainly used in ionic liquids, a chemically diverse group of industrial chemicals with numerous applications that is so far rarely studied for their occurrence in the environment. Prioritization of the findings of PM candidates is hampered by the apparent lack of toxicity data. Hence, precautionary principles and minimization approaches should be applied for the risk assessment and risk management of these substances. The large share of novel water contaminants among these findings of the suspect screening indicates that the universe of PM chemicals present in the environment has so far only scarcely been explored. Dedicated analytical methods and screening lists appear essential to close the analytical gap for PM compounds.

Synthetic cannabinoid receptor agonists and their human metabolites in sewage water: Stability assessment and identification of transformation products.

Since their first appearance in 2008, synthetic cannabinoid receptor agonists (SCRAs) remain the most popular new psychoactive substances (NPS) in the EU. Following consumption, these drugs and their metabolites are urinary excreted and enter the sewage system enabling the application of wastewater-based epidemiology (WBE). Knowing the fate of target analytes in sewage water is essential for successful application of WBE. This study investigates the stability of several chemically diverse SCRAs and selected human metabolites under sewage conditions utilizing a combination of liquid chromatography-tandem mass spectrometry and high-resolution mass spectrometry (HRMS). Target analytes included SCRAs with indole (5F-PB-22, PB-22 pentanoic acid), indazole (AMB-FUBINACA, 5F-ADB, 5F-ADB dimethylbutanoic acid), carbazole (MDMB-CHMCZCA, EG-018), and γ-carboline (Cumyl-PeGaClone) chemical core structures representing most of the basic core structures that have occurred up to now. Stability tests were performed using wastewater effluent containing 5% activated sludge as inoculum to monitor degradation processes and formation of transformation products (TPs). The majority of investigated SCRAs, excluding the selected human metabolites, was recalcitrant to microbial degradation in sewage systems over a period of 29 days. Their stability was rather controlled by physico-chemical processes like sorption and hydrolysis. Considering a typical hydraulic in-sewer retention time of 24 h, the concentration of AMB-FUBINACA decreased by 90% thus representing the most unstable SCRA investigated in this study. Among the 10 newly identified TPs, three could be considered as relevant markers and should be included into future WBE studies to gain further insight into use and prevalence of SCRAs on the drug market.

Microplastic-associated trophic transfer of benzo(k)fluoranthene in a limnic food web: Effects in two freshwater invertebrates (Daphnia magna, Chironomus riparius) and zebrafish (Danio rerio).

The continuously growing plastic production and incomplete recycling processes open manifold entry routes for microplastic particles (MPs) into the environment. Since knowledge on trophic transfer of contaminants sorbed to MPs is still insufficient for freshwater systems, the transfer of the model pollutant benzo(k)fluoranthene (BkF) sorbed to polymethyl methacrylate (PMMA) particles in a limnic food web was investigated: Two freshwater invertebrates (Daphnia magna and Chironomus riparius larvae) were selected and either left untreated, exposed to pristine PMMA, PMMA-associated BkF, or exposed to dissolved BkF (BkFaq). As second-level consumers, zebrafish (Danio rerio) were fed twice daily with pre-treated invertebrates over two days. Induction of hepatic cytochrome P450 by BkF was determined as 7-ethoxy-O-resorufin deethylase (EROD) activity. Both invertebrate species readily ingested PMMA particles, tracked via fluorescence microscopy and accumulated BkFaq, measured via GC-MS. Fluorescence signals in gastrointestinal tracts of zebrafish were quantified with confocal laser scanning microscopy (CLSM). The fluorescence signal in gastrointestinal tracts of zebrafish was not altered, whereas, EROD activity was significantly induced when zebrafish were fed with Chironomus riparius, pre-exposed to BkFaq. Trophic exposure scenarios with BkF sorbed to PMMA did not result in any alterations of investigated endpoints in both invertebrate species and zebrafish compared to controls. Given that BkF amounts were in the low ng-range, as detected by GC-MS, the transport of MP-sorbed BkF to zebrafish was less effective than direct exposure to waterborne BkFaq, and the potential threat of trophic transfer of substances such as BkF in limnic food webs may have been overestimated.

Making waves: Water-soluble polymers in the aquatic environment: An overlooked class of synthetic polymers?

Synthetic polymers have been one of the defining environmental topics of the last decade. Synthetic polymers in the environment are usually classified by their size. They encompass the widely discussed size fractions of macroplastic, microplastic, and nanoplastic. Water-soluble polymers (WSPs), however, are mostly absent in this discussion. In this paper, we argue that WSPs are produced in large quantities and have many applications that facilitate a discharge into the environment, where their fate and impact remain mostly unclear. We argue that there are yet no suitable analytical methods for the quantification of WSPs in environmental matrices and propose an analytical method that utilizes size exclusion chromatography - mass spectrometry to detect and potentially also quantify WSPs through specific fragments generated by in-source fragmentation. With the detection of polyethylene glycol in a wastewater treatment plant effluent and a surface water sample we provide a first prove of principle for the applicability of this novel analytical approach to WSPs. Ultimately, we conclude that WSPs are currently in a similar position as MP were in the advent of their investigation: We know of an environmental contamination but are uncertain of its extent and impact and still lack the tools to investigate them thoroughly.

Are (fluorinated) ionic liquids relevant environmental contaminants? High-resolution mass spectrometric screening for per- and polyfluoroalkyl substances in environmental water samples led to the detection of a fluorinated ionic liquid.

Fragmentation flagging (FF), a high-resolution mass spectrometric screening variant that utilizes intentionally produced indicative in-source fragments, was used to screen for per- and polyfluoroalkyl substances (PFASs) in surface waters. Besides expected legacy PFAS, FF enabled the detection of some rarely investigated representatives, such as trifluoromethanesulfonic acid (TFMSA). Additionally, a novel PFAS was detected and identified as tris(pentafluoroethyl)trifluorophosphate (FAP) via MS/MS experiments and confirmed with a reference standard. The first monitoring of FAP in 20 different surface waters revealed a localized contamination affecting three connected rivers with peak concentrations of up to 3.4 µg/L. To the best of our knowledge, this is the first time FAP has been detected in environmental water samples. The detection of FAP, which is exclusively used as a constituent of ionic liquids (ILs), raises questions about the environmental relevance of ILs in general and particularly fluorinated ILs. A following comprehensive literature search revealed that ILs have already been intensely discussed as potential environmental contaminants, but findings reporting ILs in environmental (water) samples are almost non-existent. Furthermore, we address the relevance of ILs in the context of persistent, mobile, and toxic chemicals, which are at present gaining increasing scientific and regulatory interest, and as part of the PFAS "dark matter" that represents the gap between the amount of fluorine originating from known PFAS and the total adsorbable organically bound fluorine. Graphical abstract.

Matrix effects in the analysis of polar organic water contaminants with HILIC-ESI-MS.

Matrix effects have been shown to be very pronounced and highly variable in the analysis of mobile chemicals, which may severely exacerbate accurate quantification. These matrix effects, however, are still scarcely studied in combination with hydrophilic interaction liquid chromatography (HILIC) and for very polar chemicals. In this study, the matrix effects of 26 polar model analytes were investigated in enriched drinking water, wastewater treatment plant effluent and solutions of inorganic salts, utilizing post-column infusion of the analytes into a HILIC-electrospray ionisation (ESI)-high-resolution mass spectrometry system. These experiments revealed the occurrence of structure-specific and unspecific matrix effects. The unspecific matrix effects were mainly observed in positive ESI polarity and predominantly coincided with a high ion count, resulting in ion suppression of all analytes. Thus, the excess charge is hypothesized to be the limiting factor in ion formation. Structure-specific matrix effects were more pronounced in negative ESI polarity and even structurally similar compounds were observed to react entirely differently: perfluoroalkyl carboxylic acids were suppressed, while perfluoroalkane sulfonic acids were simultaneously enhanced. These matrix effects were traced back to inorganic anions and cations, which eluted over a significant fraction of the chromatographic run time with this setup. Hence, it was concluded that inorganic ions are a main cause for matrix effects in the analysis of mobile chemicals utilizing HILIC. Graphical abstract.

Analysis of mobile chemicals in the aquatic environment-current capabilities, limitations and future perspectives.

Persistent and mobile water contaminants are rapidly developing into a focal point of environmental chemistry and chemical regulation. Their defining parameter that sets them apart from the majority of regularly monitored and regulated contaminants is their mobility in the aquatic environment, which is intrinsically tied to a high polarity. This high polarity, however, may have severe implications in the analytical process and thus the most polar of these mobile contaminants may not be covered by widely utilized trace-analytical methods, and thus, alternatives are required. In this review, we infer the physical and chemical properties of mobile water contaminants from a set of almost 1800 prioritized REACH chemicals and discuss the implications these substance properties may have on four integral steps of the analytical process: sampling and sample storage, sample pre-treatment, separation and detection. We discuss alternatives to widely utilized trace-analytical methods, examine their application range and limitations, highlight potential analytical techniques on the horizon and emphasize research areas we believe still offer the most room for further improvement. While we have a comprehensive set of analytical methods to cover a large portion of the known mobile chemicals, these methods are still only infrequently utilized. Graphical abstract.

Profiling of synthesis-related impurities of the synthetic cannabinoid Cumyl-5F-PINACA in seized samples of e-liquids via multivariate analysis of UHPLC-MSn data.

Vaping of synthetic cannabinoids via e-cigarettes is growing in popularity. In the present study, we tentatively identified 12 by-products found in a pure sample of the synthetic cannabinoid Cumyl-5F-PINACA (1-(5-fluoropentyl)-N-(2-phenylpropan-2-yl)-1H-indazole-3-carboxamide), a prevalent new psychoactive substance (NPS) in e-liquids, via high-resolution mass spectrometry fragmentation experiments (HRMS/MS). Furthermore, we developed a procedure to reproducibly extract this synthetic cannabinoid and related by-products from an e-liquid matrix via chloroform and water. The extracts were submitted to flash chromatography (F-LC) to isolate the by-products from the main component. The chromatographic impurity signature was subsequently assessed by ultra-high-performance liquid chromatography coupled to mass spectrometry (UHPLC-MS) and evaluated by automated integration. The complete sample preparation sequence (F-LC + UHPLC-MS) was validated by comparing the semi-quantitative signal integrals of the chromatographic impurity signatures of five self-made e-liquids with varying concentrations of Cumyl-5F-PINACA [0.1, 0.2, 0.5, 0.7 and 1.0% (w/w)], giving an average relative standard deviation of 6.2% for triplicate measurements of preparations of the same concentration and 10.5% between the measurements of the five preparations with different concentrations. Lastly, the chromatographic signatures of 14 e-liquid samples containing Cumyl-5F-PINACA from police seizures and Internet test purchases were evaluated via hierarchical cluster analysis for potential links. For the e-liquid samples originating from test purchases, it was found that the date of purchase, the identity of the online shop, and the brand name are the critical factors for clustering of samples.

Combined study of source, environmental monitoring and fate of branched alkylphenols: The chain length matters.

Alkylphenols (APs) are chemicals of largely anthropogenic origin. Longer chain derivatives like 4-nonylphenol (4NP) or 4-tert.-octylphenol (4tOP) are mainly used for the production of alkylphenol ethoxylates, while short chain alkylphenols (SCAPs) can be applied during the production of phenolic or epoxide resins that are used in paint, glue or adhesive formulations. The source, environmental distribution and fate of 4NP and 4tOP were thoroughly demonstrated leading to growing concerns regarding their endocrine properties. Although, SCAPs are also expected to entail risks to the aquatic environment, only few studies dealt with the identification of possible sources or environmental concentrations thereof. In order to evaluate the role of resin-based building materials as a possible source of 4-tert.-butylphenol (4tBP), 4-tert.-pentylphenol (4tPP), 4tOP and 4NP, 18 formulations were tested. Furthermore, AP concentrations of four wastewater treatment plants (WWTPs) and 50 surface waters were analyzed to assess and compare environmental concentrations and the discharge of APs depending on their chain length. 4tBP was the dominant AP in analyzed building materials with concentrations up to 320 g kg-1. Furthermore, APs were detected in all WWTPs and waterbodies. 4NP was the dominant AP in most surface water and WWTP samples ranging from

Halomethanesulfonic Acids-A New Class of Polar Disinfection Byproducts: Standard Synthesis, Occurrence, and Indirect Assessment of Mitigation Options.

Halomethanesulfonic acids (HMSAs) are recently discovered polar disinfection byproducts without commercially available reference materials. To allow for their accurate quantification, we successfully synthesized standards for the four presumably most prevalent HMSA congeners: chloromethanesulfonic acid, bromomethanesulfonic acid, dichloromethanesulfonic acid, and bromochloromethanesulfonic acid. After structure confirmation and quantification with high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy, we integrated them into a multilayer solid phase extraction and hydrophilic interaction liquid chromatography-tandem mass spectrometry method dedicated to the analysis of polar water contaminants. With this method we monitored HMSAs in drinking water production plants from four European countries and tap water samples taken in six countries. HMSAs were detected in the low µg/L range after the chlorination step during drinking water production, all tap waters samples, and two surface waters used for drinking water production. Concentrations in tap water samples ranged from 0.07 µg/L to 11.5 µg/L while the HMSA concentrations in surface waters were in the range of 100 ng/L. We utilized the HMSA formation potential to indirectly assess the behavior of hitherto unknown HMSA precursors, consequently identifying ozonation, filtration through activated carbon, and reverse osmosis as efficient removal tools for HMSA precursors, thus limiting their formation during subsequent water disinfection.