Per- and polyfluoroalkyl substances (PFAS) form a large chemical group, but routine monitoring targets only a few well-known compounds such as perfluorooctane sulfonic acid (PFOS). To better understand the widespread occurrence of PFAS in Dutch surface waters, we performed target analysis using an expanded list of compounds, combined with extensive suspect and de novo non-target screening (SNTS) to explore unreported PFAS beyond the scope of conventional monitoring. Analyses were performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography-trapped ion-mobility time-of-flight mass spectrometry (LC-timsTOF-MS). Target analysis focused on 24 previously underreported sulfonamide-based PFASs, enabled by newly available analytical standards and 34 common PFASs, representing 58 compounds. Several N-alkyl perfluoroalkane sulfonamidoacetic acids, including MeFBSAA (up to 50 ng/L), were found. SPr-FHxSA (N-sulfo propyl perfluorohexane sulfonamide), associated with aqueous film-forming foams (AFFFs), was detected in five samples (0.14-1.99 ng/L). In total, 38 PFAS were identified by target analysis. Collision cross-section (CCS) values of analytical standards were measured prior to SNTS. In SNTS, nineteen compounds, mainly fluorinated pharmaceuticals and pesticides, were identified at confidence level 2a using the MassBank library. Another 22 candidates were tentatively classified at levels 2b or 3, including an unsaturated PFOS analogue and a fluazinam transformation product, highlighting the ability of de novo SNTS to uncover unexpected PFAS. Finally, 6:2 fluorotelomer sulfonyl propanoamido-dimethylethyl sulfonate (6:2 FtSO2AoS) was confirmed at level 1a. Overall, integrating new PFAS standards with SNTS provided a far more complete view of PFAS presence in Dutch waters than target monitoring.

While biotransformation of chlorinated paraffins (CPs) has been demonstrated in various compartments, their hydroxylated and oxidized metabolites have only recently been identified using non-target screening approaches. The lack of authentic standards for these tentative metabolites impedes definitive structural characterization and toxicity assessment. To address this gap, reference standards for hydroxylated and carbonylated CP metabolites were synthesized, analyzed using liquid chromatography (LC) with high-resolution mass spectrometry (HRMS), and evaluated for their capacity to compete with thyroid hormone for binding to transthyretin (TTR). Matching LC-HRMS data demonstrated that the newly synthesized 3,4,7,8,10,11-hexachloro-1-undecanol and 1,2,5,8,9-pentachloro-4-undecanol (C11H17Cl6-OH and C11H18Cl5-OH) were in vitro metabolites of 1,2,4,5,8,9-hexachloroundecane (C11H18Cl6) following incubation with rat liver S9 fractions. CP single congeners exhibited limited aqueous solubility and weak TTR binding capacity. Hydroxylation increased aqueous solubility, enabling hydroxylated CPs to bind TTR at higher concentrations. In contrast, carbonylated CPs were less potent competitors than hydroxylated CPs for fluorescent thyroxine (FITC-T4) binding to TTR. This study confirms the biotransformation of CPs into hydroxylated metabolites, which may cause thyroid hormone system disruption. It is important to further investigate whether the binding of hydroxylated CPs to TTR facilitates their transport across the placenta or the blood-cerebrospinal fluid barrier, thereby posing risks to fetal development.

Synthetic cannabinoid receptor agonists (SCRAs) are a large and continuously evolving group of new psychoactive substances (NPS). Recently, many different nitrile-containing SCRAs have emerged on the illicit market, two of which have been found to release cyanide during metabolism. This can produce symptoms similar to those of cyanide poisoning, contributing to the toxicity of these SCRAs. Notified by the EU Early Warning System in 2020, Benzyl-4CN-BUTINACA (Benzyl-4CN-BINACA, BZ-4CN-BUTINACA) is the most recent nitrile-containing SCRA to emerge. This study characterized the metabolism of Benzyl-4CN-BUTINACA and the prophetic compound MDMB-4CN-BUTINACA for the first time using ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QToF-MS) following incubation with primary human hepatocytes (HHeps; 5 µmol/L, up to 5 h). For Benzyl-4CN-BUTINACA, nine metabolites (no phase II metabolites) were identified and 12 for MDMB-4CN-BUTINACA, including only two minor phase II metabolites. By far the most abundant metabolites for Benzyl-4CN-BUTINACA were metabolites with a dihydrodiol on the indazole core (B1) and decyanation to a carboxylic acid (B2). The metabolites with ester hydrolysis (M1) and ester hydrolysis with dehydrogenation (M2) were the most abundant for MDMB-4CN-BUTINACA. Decyanation was less prevalent for these compounds than for other nitrile-containing SCRAs, such as Cumyl-4CN-BUTINACA, with only 29.0% and 1.78% of metabolites of Benzyl-4CN-BUTINACA and MDMB-4CN-BUTINACA, respectively, having a loss of cyanide. However, the second major metabolite of Benzyl-4CN-BUTINACA was a decyanation metabolite, making the potential CN formation not negligible.

Per- and polyfluoroalkyl substances (PFAS) are a large group of man-made compounds used, for example, as water and oil repellents to protect textiles and fabrics. Due to a growing concern about some of these compounds, industries have introduced new PFAS varieties with supposedly less harmful properties. In this study, different fabric samples from carpets, curtains and sofas (n = 30) were analyzed after a solvent extraction and an Envi-Carb clean-up for 81 PFAS, including legacy PFAS and 43 newly synthesized precursors, mainly perfluoroalkane sulfonamide derivatives by liquid and gas chromatography - mass spectrometry. In total, 28 PFAS were detected in the fabric samples. Fluorotelomer alcohols showed the highest concentrations in the fabrics (1-2329 μg/m2). Perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl acids (PFAAs) were also detected but at lower concentrations (e.g., 0.02-1.71 μg/m2 for PFHxA, 0.01-1.97 μg/m2 for PFBS). Perfluoroalkane sulfonamide precursors such as MeFBSAA, FBSE, MeFBSE, FBSA, and MeFBSEA were primarily found in carpet and curtain samples, accounting for approximately 10 % and 24 % of the total PFAS concentration in these matrices, respectively. These precursors were predominantly fully fluorinated compounds with 4-carbon chains. These precursors mostly correspond to fully fluorinated 4-carbon chain-PFAS and may be in accordance with the higher use of shorter PFAS compounds observed in recent years but more samples should be tested to confirm this assumption.

Chlorinated paraffins (CPs) are emerging environmental contaminants with limited biotransformation data because of the complexity of CP technical mixtures and the lack of single congener standards. In this study, novel single CP congeners, with similar chlorine patterns to those found in technical mixtures, were incubated for 60 min with rat hepatic subcellular fractions to evaluate their relative biotransformation extent and identify their potential metabolites. Results demonstrated that these CP congeners were metabolized by phenobarbital and 5,6-benzoflavone-induced rat liver S9, following 1st-order kinetics. The 1st-order rate constants were logarithmically inversely related to the chain lengths at a given number of chlorine atoms. In turn, the chlorine positions affected the biotransformation pathways, resulting in the formation of different metabolites. Metabolites identified by high-resolution mass spectrometric analysis included (multi-)hydroxylated, carbonyl, carboxylic, and chain-shortened products. Hydrolytic and oxidative dechlorination, stepwise hydroxylation/oxidation, and C-C bond cleavage were identified as potential biotransformation pathways. A notable transformation of initial hydroxylated metabolites further into aldehydes and carboxylic acids (ω-oxidation) was emphasized. The study's results fill the knowledge gap in CP biotransformation and provide structural information on potentially bioactive CP metabolites for future synthesis and toxicity studies.

Perfluorooctane sulfonamide derivatives have been extensively used by industry for their surfactant properties and as building blocks for other perfluoroalkyl substances (PFAS). Due to their environmental impact and their potential degradation to other harmful PFAS, short-chain sulfonamide derivatives alternatives were introduced. However, these are now also suspected to be present in different environmental matrices and there is a lack of labelled and unlabelled reference standards to perform analyses. To address this gap, 40 native and deuterium labelled short-chain perfluoroalkane sulfonamide derivatives were synthesized, utilizing commercial perfluoroalkane sulfonyl fluoride as starting materials. All products were synthesized and then purified to obtain linear n-isomer reference standards. NMR, GC-FID-MS and LC-MS techniques were used for product identification and purity assessment. Recrystallization method was developed to selectively isolate the n-isomer from the isomer mixtures, thereby providing valuable reference and internal standards for environmental and toxicological investigations.

Background: Chlorinated paraffins (CPs) are industrial chemicals categorised as persistent organic pollutants because of their toxicity, persistency and tendency to long-range transport, bioaccumulation and biomagnification. Despite having been the subject of environmental attention for decades, analytical methods for CPs still struggle reaching a sufficient degree of accuracy. Among the issues negatively impacting the quantification of CPs, the unavailability of well -characterised standards, both as pure substances and as matrix (certified) reference materials (CRMs), has played a major role. The focus of this study was to provide a matrix CRM as quality control tool to improve the comparability of CPs measurement results. Results: We present the process of certification of ERM (R)-CE100, the first fish reference material assigned with certified values for the mass fraction of short -chain and medium -chain chlorinated paraffins (SCCPs and MCCPs, respectively). The certification was performed in accordance with ISO 17034:2016 and ISO Guide 35:2017, with the value assignment step carried out via an intercomparison of laboratories of demonstrated competence in CPs analysis and applying procedures based on different analytical principles. After confirmation of the homogeneity and stability of the CRM, two certified values were assigned for SCCPs, depending on the calibrants used: 31 +/- 9 mu g kg - 1 and 23 +/- 7 mu g kg - 1 . The MCCPs certified value was established as 44 +/- 17 mu g kg - 1 . All assigned values are relative to wet weight in the CRM that was produced as a fish paste to enhance similarity to routine biota samples. Significance and novelty: The fish tissue ERM-CE100 is the first matrix CRM commercially available for the analysis of CPs, enabling analytical laboratories to improve the accuracy and the metrological traceability of their measurements. The certified CPs values are based on results obtained by both gas and liquid chromatography coupled with various mass spectrometric techniques, offering thus a broad validity to laboratories employing different analytical methods and equipment.

The illegal use of opiates and cocaine is a challenge world-wide, but some derivatives are also valuable pharmaceuticals. Reference samples of the active ingredients and their metabolites are needed both for controlling administration in the clinic and to detect drugs of abuse. Especially, (13)C-labeled compounds are useful for identification and quantification purposes by mass spectroscopic techniques, potentially increasing accuracy by minimizing ion alteration/suppression effects. Thus, the synthesis of [acetyl-(13)C4]heroin, [acetyl-(13)C4-methyl-(13)C]heroin, [acetyl-(13)C2-methyl-(13)C]6-acetylmorphine, [N-methyl-(13)C-O-metyl-(13)C]codeine and phenyl-(13)C6-labeled derivatives of cocaine, benzoylecgonine, norcocaine and cocaethylene was undertaken to provide such reference materials. The synthetic work has focused on identifying (13)C atom-efficient routes towards these derivatives. Therefore, the (13)C-labeled opiates and cocaine derivatives were made from the corresponding natural products.

Stable isotope-labeled internal standards (SIL-ISs) are often used when applying liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze for legal and illegal drugs. ISs labeled with C-13, N-15, and O-18 are expected to behave more closely to their corresponding unlabeled analytes, compared with that of the more classically used H-2-labeled ISs. This study has investigated the behavior of amphetamine, H-2(3)-, H-2(5,) H-2(6)-, H-2(8)-, H-2(11)- and C-13(6)-labeled amphetamine, during sample preparation by liquid-liquid extraction and LC-MS/MS analyses. None or only minor differences in liquid-liquid extraction recoveries of amphetamine and the SIL-ISs were observed. The chromatographic resolution between amphetamine and the H-2-labeled amphetamines increased with the number of H-2-substitutes. For chromatographic studies we also included seven additional C-13(6)-amphetamines and their analytes. All the C-13(6)-labeled ISs were co-eluting with their analytes, both when a basic and when an acidic mobile phase were used. MS/MS analyses of amphetamine and its SIL-ISs showed that the ISs with the highest number of H-2-substitutes required more energy for fragmentation in the collision cell compared with that of the ISs with a lower number. The findings, in this study, support those of previous studies, showing that C-13-labeled ISs are superior to H-2-labeled ISs, for analytical purposes. (C) 2014 Elsevier B.V. All rights reserved.

(−)-∆9-Tetrahydrocannabinol is the principal psychoactive component of the cannabis plant and also the active ingredient in some prescribed drugs. To detect and control misuse and monitor administration in clinical settings, reference samples of the native drugs and their metabolites are needed. The accuracy of liquid chromatography/mass spectrometric quantification of drugs in biological samples depends among others on ion suppressing/alteration effects. Especially, 13C-labeled drug analogues are useful for minimzing such interferences. Thus, to provide internal standards for more accurate quantification and for identification purpose, synthesis of [13C4]-∆9-tetrahydro-cannabinol and [13C4]-11-nor-9-carboxy-∆9-tetrahydrocannabinol was developed via [13C4]-olivetol. Starting from [13C4]-olivetol the synthesis of [13C4]-11-nor-9-carboxy-∆9-tetrahydrocannabinol was shortened from three to two steps by employing nitromethane as a co-solvent in condensation with (+)-apoverbenone.

The availability of high‐quality 13C‐labelled internal standards will improve accurate quantification of narcotics and drugs in biological samples. Thus, the synthesis of 10 [13C6]‐labelled phenethylamine derivatives, namely amphetamine, methamphetamine, 3,4‐methylenedioxyamphetamine, 3,4‐methylenedioxymethamphetamine, 3,4‐methylenedioxy‐N‐ethylamphetamine, 4‐methoxyamphetamine, 4‐methoxymethamphetamine, 3,5‐dimethoxyphenethylamine 4‐bromo‐2,5‐dimethoxyphenethylamine and 2,5‐dimethoxy‐4‐iodophenethylamine, have been undertaken. [13C6]‐Phenol proved to be an excellent starting material for making 13C‐labelled narcotic substances in the phenethylamine class, and a developed Stille‐type coupling enabled an efficient synthesis of the 3,4‐methylenedioxy and 4‐methoxy derivatives. The pros and cons of alternative routes and transformations are also discussed. The [13C6]‐labelled compounds are intended for use as internal standards in forensic analysis, health sciences and metabolomics studies by gas chromatography‐mass spectrometry and liquid chromatography‐tandem mass spectrometry. Copyright © 2014 John Wiley & Sons, Ltd.

Polybrominated diphenyl ethers (PBDEs) have become widely distributed as environmental contaminants due to their wide-spread use as flame retardants. Their structural similarity to other halogenated organic pollutants, for example polychlorinated biphenyls (PCBs), has led to speculation that they may have similar toxicological properties and effects. Recent focus on PBDEs as possible priority pollutants has also led to an increasing need for reference standards of PBDEs for toxicological studies and for environmental analysis. In this work we synthesized a series of fluorinated PBDEs (F-PBDEs) which can be used as possible internal standards, as an alternative to high-cost alternatives, such as the (13)C-labelled analogues. F-PBDEs have been synthesized by using different coupling reactions and by bromination of fluorinated starting materials.

Four new difluorinated tetra- and pentabromo BDE internal standards for GC–MS/GC–ECD analysis, 2F-BDE 47, 2F-BDE 85, 2F-BDE 99 and 2F-BDE 119, have been prepared in 98–99.0% purity, mainly by coupling of the new tribromodifluorophenols (19–21) and symmetrical bromodiphenyliodonium salts (8, 22). The four difluorinated BDEs showed promising properties as internal standards for quantitative BDE analysis. Tetra-, penta-, hexa- and hepta-brominated BDE reference standards, BDE 75, BDE 85, BDE 138 and BDE 183, were also prepared in 98.4–99.8% purity and characterised.