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
