酶联免疫吸附分析法测定黄瓜中的甲基对硫磷

采用自制多克隆抗体，考察了不同离子强度和不同甲醇含量对竞争反应的影响，并对反应体系进行了优化，最终建立了黄瓜中甲基对硫磷的残留检测ELISA方法。实验表明，甲基对硫磷对抗体竞争性结合的I50为0.13 mg/L，方法检出限I20 为6.7 μg/L。除倍硫磷与杀螟硫磷表现了一定的交叉反应外，其它结构相类似的有机磷农药均无交叉反应。黄瓜样品经简单前与处理后分别采用ELISA和GC测定，用ELISA方法测得黄瓜中甲基对硫磷的添加回收率为83.10%~93.46%，C.V为6.61%~10.36%，最低检出限为 0.003mg/kg，与GC测定数据基本相符，符合农药残留分析的要求。

Determination of Parathion-methyl in cucumber by ELISA

Using the self-made poly-clonal antibody, the affect of the ion-strength and the methanol concentration to the competitive reaction were investigated, and the reaction system was optimized. An indirect competitive enzyme-linked immunosorbent assay (ELISA) for the determination of parathion-methyl in cucumber was developed. The results showed that the concentration of parathion-methyl that inhibits 50% of antibody-antigen binding（I50）was 0.13 mg/L, the detection limit I20 was 6.7 μg/L. Most analogues showed negligible cross-reactivity except for fenthion and fenitrothion. Cucumber samples were detected with ELISA and GC after simple pre-procession. The fortified recovery of ELISA were 83.10%~93.46%，CV were 6.61%~10.36%，the determination limit was 0.003mg/kg. The results of the ELISA were verified by GC method.