HPLC测定水体中毒死蜱及其有毒降解产物TCP

通过比较不同的提取溶剂和使用量，就水体中毒死蜱和TCP残留提取的效果及不同的流动相组成和比例对毒死蜱和TCP测定的影响，建立了水体中毒死蜱及TCP的HPLC残留分析方法。结果表明，水体中毒死蜱和TCP最佳提取溶剂为乙酸乙酯，提取次数为2次，用量分别为50和30mL。色谱条件为：流动相为甲醇：水=90：10或乙腈：水=90：10，流速1mL·min^-1；紫外检测波长300nm。当流动相为甲醇：水=90：10时，毒死蜱和TCP的保留时间分别为6．4和3．6min；当流动相为乙腈：水=90：10时，其保留时间分别为5．6和2．5min。毒死蜱和TCP的检出限分别为0．5和0．15ng。当毒死蜱和TCP在水中的添加浓度为0．01～5mg·L^-1时，标准添加回收率分别为91．4％-105．1％和90．6％～105．4％，变异系数分别为0．99％～4．12％和0．29％～9．33％。水样中毒死蜱和TCP的最小检出浓度分别为2和0．6ng·mL^-1。

Residue Analysis of Chlorpyrifos and Its Toxic Metabolite TCP in Water by HPLC

A method was developed for analysis the residues of chlorpyrifos and its toxic metabolite 3,5,6-trichloro-2-pyridinol（TCP） in water. In this method, different conditions of mobile phase, different kinds of extraction solvents and different amount of extraction solvents were studied. Ethyl acetate, dichloromethane, chloroform and petroleum ether were tested as the extraction solvent, respectively. And the best extraction was obtained when using ethyl acetate as extraction solvent. Water samples were extracted by two step liquid-liquid distribution, 50 mL ethyl acetate was used in the first partitioning step, and 30 mL was used in the second. The detection method was based on using high-performance liquid chromatography （HPLC） with reversed-phase C18 column, and gradient UV detector. The column was maintained at 25 ℃ with a mobiie phase flow rate of 1.0 mL· min^-1. The mobile phase was consisted of methanol-water（90：10, V/V ） or acetonitrile-water（90：10, V/V）. Chlorpyrifos and TCP were all detected at 300 nm. The retention times of chlorpyrifos and TCP were 6.4 min and 3.6 min when using methanol-water （90：10, V/V） as mobile phase, and 5.6 min and 2.5 min when using acetonitrile-water（90：10, V/V）. The detection limits for ehlorpyrifos and TCP were found to be 0.5 ng and 0. 15 ng, respectively. When adding chlorpyrifos and TCP at the concentration of0.01-5 mg·L^-1, the average recoveries of chlorpyrifos and TCP from water samples were about 91.4%-105.1% and 90.6%-105.4%, and the relative standard deviation ranged from 0.99%-4.12% to 0.29%-9.33%. The lowest detectable concentration of chlorpyrifos and TCP in water sample were 2 ng· mL^-1 and 0.6 ng· mL^-1. The results showed that the method met the demands of pesticide residue analysis.