表面活性剂对酶抑制光度法测定有机磷农药的增敏和终止作用

Determination of Sensitizer and Terminator of Organophosphorus Pesticides by Enzyme Inhibition Photometry with Surfactant

研究3种不同类型的表面活性剂,对聚乙烯醇固定化乙酰胆碱酯酶(PVA-AChE)活性的影响。选用十六烷基三甲基溴化铵(CTAB)作酶促反应体系的增敏和终止剂,0.6g·L-1CTAB使酶促反应增敏27%,5g·L-1CTAB对酶促反应终止作用良好,优化了实验条件,初探了作用机理。用建立的方法测定马拉硫磷的检出限为1.8×10-9g·L-1,线性范围为8—160ng·mL-1,11次测定马拉硫磷(50ng·mL-1)的相对标准偏差为2.8%;用于测定小白菜样品中马拉硫磷的回收率为88.8%—95.6%。

The influences of the three different types of surfactant on the activity of poly（vinyl alcohol） alcohol immobilized cholinesterase （PVA-AChE）were investigated. Cetrimonium bromide （CTAB） was used as sensitizer and terminator of enzymatic reaction system, the sensitivity of enzymatic reaction increased 27% under 0. 6g ·L-1 CTAB,and the effect on terminating enzymatic reaction was good under 5g ·L-1 CTAB,then the experimental conditions were optimized and the reaction mechanism was discussed. The detection limit of malathion wasl. 8 × 10-9g ·L-1 and linear range was in the range of 8--160ng · mL-1, and the relative standard deviation （50ng·mL-1,n = 11） was 2.8 %. The method is applied to the determination of malathion in samples of cabbage with the recoveries of 88.8%--95.6%.