Stereoselective Separation and Acute Toxicity of Tau-Fluvalinate to Zebrafish

Abstract

Tau-fluvalinate (TFLV) is one of the most potent chiral synthetic pyrethroids to control a wide range of pests in agricultural fields, especially in apiary. In this study, two stereoisomers of TFLV were fully separated by high-performance liquid chromatography (HPLC) with a semipreparative chiral column using cellulose-tris(3,5-dimethylphenylcarbamate) as chiral stationary phase and n-hexane and 2-propanol (96/4, v/v) as mobile phase at a flow rate of 2.5 mL min ⁻¹. The (+)-stereoisomer was first eluted by detecting with an optical rotation detector. After obtaining pure single stereoisomer of TFLV, acute toxicities of each isomer and TFLV standard to zebrafish were evaluated. The results showed that the (+)-stereoisomer exhibited 273.4 times higher toxicity than the (−)-stereoisomer and 6.7 times higher than TFLV standard, according to their LC ₅₀values at 96 h after exposure. This indicates that the toxicity of TFLV mainly originates from (+)-stereoisomer. These results are very helpful to prepare single stereoisomer of chiral pesticides and evaluate their different toxicological effects to aquatic organisms.