Qualitative Multiresidue Screening Method for 143 Veterinary Drugs and Pharmaceuticals in Milk and Fish Tissue Using Liquid Chromatography Quadrupole-Time-of-Flight Mass Spectrometry

A wide-scope screening methodology has been developed for the identification of veterinary drugs and pharmaceuticals in fish tissue and milk using ultrahigh-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). The method was validated using a qualitative approach at two concentration levels. The detection of the residues was accomplished by retention time, accurate mass, and the isotopic fit using an in-house database. Product-ion spectra were used for unequivocal identification of the compounds. Generic sample treatment was applied. The majority of the compounds were successfully detected and identified at concentration levels of 150 ng mL^–1 in milk and 200 μg kg^–1 in fish (>80% of the compounds in both matrices), whereas satisfactory results were also obtained at concentration levels of 15 ng mL^–1 in milk and 20 μg kg^–1 in fish (>60% of the compounds detected and identified)

Assessment of the Acute Toxicity, Uptake and Biotransformation Potential of Benzotriazoles in Zebrafish (<i>Danio rerio</i>) Larvae Combining HILIC- with RPLC-HRMS for High-Throughput Identification

The current study reports on the toxicity, uptake, and biotransformation potential of zebrafish (embryos and larvae) exposed to benzotriazoles (BTs). Acute toxicity assays were conducted. Cardiac function abnormalities (pericardial edema and poor blood circulation) were observed from the phenotypic analysis of early life zebrafish embryos after BTs exposure. For the uptake and biotransformation experiment, extracts of whole body larvae were analyzed using liquid chromatography–high-resolution tandem mass spectrometry (UPLC-Q-TOF-HRMS/MS). The utility of hydrophilic interaction liquid chromatography (HILIC) as complementary technique to reversed phase liquid chromatography (RPLC) in the identification process was investigated. Through HILIC analyses, additional biotransformation products (bio-TPs) were detected, because of the enhanced sensitivity and better separation efficiency of isomers. Therefore, reduction of false negative results was accomplished. Both oxidative (hydroxylation) and conjugative (glucuronidation, sulfation) metabolic reactions were observed, while direct sulfation proved the dominant biotransformation pathway. Overall, 26 bio-TPs were identified through suspect and nontarget screening workflows, 22 of them reported for the first time. 4-Methyl-1-<i>H</i>-benzotriazole (4-MeBT) demonstrated the highest toxicity potential and was more extensively biotransformed, compared to 1-<i>H</i>-benzotriazole (BT) and 5-methyl-1-<i>H</i>-benzotriazole (5-MeBT). The extent of biotransformation proved particularly informative in the current study, to explain and better understand the different toxicity potentials of BTs

Determination of Benzotriazoles and Benzothiazoles in Human Urine by Liquid Chromatography-Tandem Mass Spectrometry

Benzotriazole (BTR) and benzothiazole (BTH) derivatives are used in a wide variety of industrial and consumer products and have been reported to occur in the environment. Owing to a lack of analytical methods, human exposure to BTR and BTH is still unknown. In this study, a liquid chromatography-electrospray ionization tandem mass spectrometry (LC–ESI­(+)­MS/MS) method was developed for simultaneous determination of five 1,2,3-benzotriazoles and five 1,3-benzothiazoles in human urine. The target benzotriazoles were 1<i>H</i>-benzotriazole, 1-hydroxy-benzotriazole, tolyltriazole, xylyltriazole (or 5,6-dimethyl-1<i>H</i>-benzotriazole), and 5-chloro-benzotriazole, and the target benzothiazoles were benzothiazole, 2-hydroxy-benzothiazole, 2-methylthio-benzothiazole, 2-amino-benzothiazole, and 2-thiocyanomethylthio-benzothiazole. Urine specimens were enzymatically deconjugated with β-glucuronidase and extracted by a solid-phase extraction (SPE) procedure for the measurement of total concentrations (i.e., free + conjugated forms) of BTRs and BTHs. Additionally, a liquid–liquid extraction (LLE) method was developed for comparison of extraction efficiencies between SPE and LLE. The limits of detection (LODs) ranged from 0.07 (2-amino-benzothiazole) to 4.0 ng/mL (benzothiazole) for the SPE method and from 0.04 (tolyltriazole) to 6.4 ng/mL (benzothiazole) for the LLE method. A total of 100 urine specimens, collected from Athens, Greece, were analyzed by enzymatic deconjugation and SPE. Benzothiazole and tolyltriazole were found frequently, and their concentrations were on the order of a few ng/mL. To our knowledge, this is the first study on the occurrence of 10 BTR and BTH compounds in human urine

Mass Loading and Fate of Linear and Cyclic Siloxanes in a Wastewater Treatment Plant in Greece

The occurrence and fate of 5 cyclic (D3 to D7) and 12 linear (L3 to L14) siloxanes were investigated in raw and treated wastewater (both particulate and dissolved phases) as well as in sludge from a wastewater treatment plant (WWTP) in Athens, Greece. Cyclic and linear siloxanes (except for L3) were detected in all influent wastewater and sludge samples at mean concentrations of (sum of 17 siloxanes) 20 μg L^–1 and 75 mg kg^–1, respectively. The predominant compounds in wastewater were L11 (24% of the total siloxane concentration), L10 (16%), and D5 (13%), and in sludge were D5 (20%) and L10 (15%). The distribution of siloxanes between particulate and dissolved phases in influents differed significantly for linear and cyclic siloxanes. Linear siloxanes showed higher solid–liquid distribution coefficients (log <i>K</i>_d) than did cyclic compounds. For 10 of the 16 compounds detected in influents, the removal efficiency was higher than 80%. Sorption to sludge and biodegradation and/or volatilization losses are important factors that affect the fate of siloxanes in WWTPs. The mean total mass of siloxanes that enter into the WWTP via influent was 15.1 kg per day^–1, and the mean total mass released into the environment via effluent was 2.67 kg per day^–1