气相色谱氮磷检测器法用于大米和面粉中22种有机磷和有机氮农药多残留检测

Multiresidue Determination of Organophosphorous and Organonitrogen Pesticides in Rice and Flour by Gas Capillary Chromatography with Nitrogen-Phosphorus Detection

选择气相色谱氮磷检测器法检测大米、面粉中22种有机磷和有机氮农药多残留。大米、面粉样品用丙酮/二氯甲烷(1∶1,V/V)提取,二氯甲烷萃取,丙酮定容,GC-NPD检测。结果表明,该方法分离度较好,灵敏度高,方法的最小检出量在5.180×10-12～8.541×10-11g之间。当添加浓度在0.02～2.00mg·kg-1范围时,大米平均添加回收率为71.71%～109.16%,变异系数为1.16%～12.89%;面粉平均添加回收率为73.87%～113.48%,变异系数为1.75%～15.17%。该方法完全符合农药残留量检测的技术要求,是一种快速有效的分析检测方法,适合在实践中推广使用。

Nitrogen-phosphorus detector of Gas Capillary Chromatograph is characterized by high efficiency, high sensitivity and rapidity, especially, rubidium of NPD is used to have good selection and sensitivity to compounds containing nitrogen and phosphorus. Meanwhile as organophosphorous pesticides and organonitrogen pesticides such as methamidophos and aeephate are volatile and decompose easily, a method was established to detect 22 organophosphorous and organonitrogen pesticides residue simultaneously in rice and flour by NPD of gas capillary chromatography. Rice and flour samples were extracted by acetonedichloromethane, re-extracted by dichloromethane, then final residue was detected by gas capillary chromatography. The results showed that the minimum detection limits were in an arrange of 5.180×10^12g to 8.541×10^11g with high separated degree and wide linear relation .When fortified level ranged from 0.02 to 2.00 mg·kg^-1, the recoveries were found to be 71.71% to 109.16% with coefficients of variation ranged from 1.16% to 12.89% in rice, while from 73.87% to 113.48% with coefficients of variation ranged from 1.75% to 15.17% in flour. The method was rapid and praetieal analysis deteetion method that was in line with request of pestieide residue determination. It is suggested that the method be popularized and applied to praetiee.