以温州蜜柑‘国庆一号’为试材,探讨柑橘果实中乐果、杀扑磷、毒死蜱3种有机磷农药残留的提取和分析方法及毒死蜱在柑橘果实中的降解规律。结果表明:对样品进行前处理可达到较好提取效果;对液相色谱检测条件优化后,建立了提取和检测柑橘中乐果、杀扑磷、毒死蜱的固相萃取—高效液相色谱方法,用该方法对3种有机磷农药最低检测限分别为0.244、0.306及0.409μg·mL-1,回收率(74.76%~99.16%)和精密度(相对标准偏差1.01%~10.08%)达到单次洗脱进行多残留分析的要求。毒死蜱降解动态研究表明:其残留量和降解速率果皮中都比果肉中快,喷药30d后果实中残留极少;在果皮中的半衰期为10.71~10.88d,果肉中的半衰期为13.55~13.85d;1∶1000和1∶2000两种用药浓度对柑橘果实中残留量的影响差异不大。
Conditions for pretreatment and determination of organophosphorus pesticide residues contained in fruits of Citrus unshiu Marc.‘Guoqing 1' were optimized.Furthermore,the dynamical regularity of chlorpyrifos in citrus fruits was studied.The results showed that pretreatment techniques were suitable for citrus sample.The limits of detection for dimethoate,methidathion and chlorpyrifos were 0.244,0.306 and 0.409 μg·mL-1 respectively,the average recoveries were from 74.76% to 99.16%,and the relative standard derivation(RSD)were between 1.01% and 10.08%,which met the requirements of multiple residues analysis in a single run.More pesticide residues and faster dynamical regularity of chlopyrifos were found in the peel than in the pulp of citrus,and almost no residue was found in fruits after 30 days of spraying.The half-life of the pesticide was significantly different between the citrus fruits treated with different pesticide concentrations.The degeneration of chlorpyrifos residue in citrus peel and pulp were 10.71-10.88 d and 13.55-13.85 d respectively.