黄瓜中醚菌酯的残留及风险评估

建立了醚菌酯在黄瓜中的残留分析方法,并在广州和天津进行了30%醚菌酯可湿性粉剂在黄瓜上残留的田间试验,研究了醚菌酯在黄瓜上的消解动态和最终残留,采用风险商值法对黄瓜中醚菌酯可能产生的膳食风险进行了评估。黄瓜样本用乙腈提取,高效液相色谱-串联质谱法(HPLC-MS/MS)检测。在添加水平为0.01、0.05和0.5 mg/kg时,平均添加回收率在91%～95%之间,相对标准偏差为3.74%～9.99%,检出限(LOD)为0.001 mg/kg,定量限(LOQ)为0.01 mg/kg。田间试验结果表明,醚菌酯在广州和天津黄瓜中的半衰期分别为1.5 d和2.1 d,消解迅速,施药3 d后最终残留量为0.08～0.23 mg/kg,施药5 d后最终残留量均低于LOQ值。风险评估结果表明,施药后3 d时黄瓜中醚菌酯的残留风险商值均远远低于1。表明喷施30%醚菌酯可湿性粉剂防治黄瓜白粉病,按照推荐剂量使用对人体健康是安全的。

Residue and risk assessment of kresoxim-methyl in cucumber under field conditions

A rapid and effective method was developed for determination of kresoxim-methyl residue in cucumber.Field trials were designed to evaluate the dissipation and residue of kresoxim-methyl in cucumber at Guangzhou and Tianjin.The dietary exposure and risk assessment were also conducted by using the calculation of risk quotient(RQ).The samples were extracted by acetonitrile and detected by HPLC-MS/MS.The results showed good average recoveries of 91%-95% with relative standard deviations of 3.74%-9.99% at the spiked level of 0.01,0.05 and 0.5 mg/kg.The limit of detection(LOD) was 0.001 mg/kg and the limit of quantification(LOQ) was 0.01 mg/kg.The results were found that the half lives of kresoxim-methly in cucumber of Guangzhou and Tianjin were 1.5 and 2.1 days,respectively,and the terminal residue was 0.08-0.23 mg/kg 3 days after application,and lower than LOQ value 5 days after application,the RQ of kresoxim-methyl were far below 1.It predicted that it was safe for human being when using this pesticide to control powdery mildew on cucumber.