Study on Enantioselective Enrichment Metabolism of Mefentrifluconazole in Zebrafish by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

A method for investigation of enantioselective biological effects of chiral fungicide mefentrifluconazole on zebrafish to provide reference for assessment of biosafety and human health risks in aquatic environment by ultra-high performance liquid chromatography-tandem mass spectrometry was developed in this study. On the basis of acute toxicity test for 96 h, the enantioselective uptake-metabolism, metabolites and metabolic pathways of mefentrifluconazole in zebrafish were investigated by high resolution mass spectrometry. The results showed that mefentrifluconazole was moderately toxic to zebrafish, and the toxicity order was S-mefentrifluconazole > Rac- mefentrifluconazole > R-mefentrifluconazole. Among which, S-mefentrifluconazole was 2.0 and 1.4 times more toxic than R- and Rac-mefentrifluconazole, respectively. The enantioselective uptake-metabolism behavior in zebrafish manifested that R-mefentrifluconazole was preferentially enriched and metabolized in low-concentration treatment group. Finally, eight metabolites of mefentrifluconazole in zebrafish were identified. It was speculated that the main metabolic pathway was the formation of phase I metabolites through hydroxylation reaction, and then the formation of sulfate compounds and glucuronic acid complexes under the action of sulfotransferase and glucuronic acid glucuronase. The hydroxylated metabolite M074 and the glucuronide complexes M035 and M045, as well as the sulfate compounds M057 and M071, were identified for the first time in zebrafish.