Department of Applied Chemistry, China Agricultural University, Beijing 100193, China.
J Agric Food Chem. 2009 Sep 23;57(18):8545-9. doi: 10.1021/jf902420a.
The enantioselectivities of individual enantiomers of benalaxyl in acute toxicity and bioaccumulation in earthworm ( Eisenia fedtia ) were studied. The acute toxicity was tested by paper contact test. After 48 h of exposure, the calculated LC(50) values of the R-(-)-form, rac-form, and S-(+)-form were 4.99, 5.08, and 6.66 microg/cm(2), respectively. After 72 h of exposure, the calculated LC(50) values were 1.23, 1.73, and 2.45 microg/cm(2), respectively. Therefore, the acute toxicity of benalaxyl enantiomers was enantioselective. A method for determining residues of the two enantiomers of benalaxyl in earthworm tissue by high-performance liquid chromatography based on cellulose tri-(3,5-dimethylphenyl-carbamate) chiral stationary phase was developed. During the bioaccumulation experiment, the enantiomer fraction in earthworm tissue was maintained approximately at 0.6, whereas enantiomer fraction in spiked soil was maintained at 0.5; in other words, the bioaccumulation of benalaxyl was enantioselective in earthworm tissue. Peak-shaped accumulation curves were observed for both enantiomers, and the calculated biota to soil accumulations (kg dry kg(-1) wet weight) at steady state were below 1 for both enantiomers. During the elimination experiment, 79.0% of R-(-)-enantiomer and 89.6% of S-(+)-enantiomer in earthworm tissue were eliminated within 2 days.
研究了苯并恶唑对蚯蚓（赤子爱胜蚓）急性毒性和生物累积的单个对映体的对映选择性。采用纸接触试验进行急性毒性测试。暴露 48 h 后，R-(-)-型、rac-型和 S-(+)-型的计算 LC(50) 值分别为 4.99、5.08 和 6.66 μg/cm(2)。暴露 72 h 后，计算 LC(50) 值分别为 1.23、1.73 和 2.45 μg/cm(2)。因此，苯并恶唑对映体的急性毒性具有对映选择性。建立了一种基于纤维素三-(3,5-二甲基苯基氨基甲酸酯)手性固定相的高效液相色谱法测定蚯蚓组织中苯并恶唑两种对映体残留量的方法。在生物累积实验中，蚯蚓组织中对映体分数保持在约 0.6，而添加土壤中的对映体分数保持在 0.5；也就是说，苯并恶唑在蚯蚓组织中的生物累积具有对映选择性。两种对映体均观察到峰形累积曲线，两种对映体在稳态下的生物量与土壤的积累（kg 干重/kg 湿重）均低于 1。在消除实验中，蚯蚓组织中 R-(-)-对映体的 79.0%和 S-(+)-对映体的 89.6%在 2 天内被消除。
