固相萃取-气相色谱法测定玉米中有机氯和拟除虫菊酯农药残留量

摘要

Objective To develop a method for the simultaneous determination of organic chlorine and pyrethroid pesticides residues in corn by gas chromatography with ECD detector.Methods Corn samples were extracted with acetonitrile by ultra-sonic, and the extracts were purified by solid phase extraction using Florisil, then samples were detected by GC-ECD after concentrated by nitrogen flushing.ResultsThe method showed a good linearity in the range of 0.01~0.5 mg/L for organic chlorine and pyrethroid pesticides with R2>0.99. The recoveries were in the range of 71.0%~103% at 3 spiked levels of 0.02, 0.05, and 0.2 mg/kg for organic chlorine and pyrethroid pesticides, and the relative standard deviations (RSDs) were 1.28%~8.74%. The limit of detection was in the range of 0.1~16μg/kg.Conclusion The method is suitable for quantitative and qualitative determination of organic chlorine and pyrethroid pesticides residues in a large number of corn samples with a sample and fast pretreatment procedure. Meanwhile, samples can be effectively cleaned up, and it could meet the requirements of daily inspection and supervision work.%目的：建立气相色谱-电子捕获检测器法(GC-ECD)测定玉米中16种有机氯和拟除虫菊酯农药残留量的方法。方法玉米样品经乙腈超声提取后，使用Florisil进行固相萃取净化，样品经氮吹浓缩后，使用气相色谱电子捕获检测器测定。结果16种有机氯和拟除虫菊酯农药在0.01~0.5 mg/L浓度范围内呈现良好线性关系， R2大于0.99；在0.02、0.05、0.2 mg/kg三个添加浓度上回收率范围为71.0%~103%，相对标准偏差1.28%~8.74%，检出限在0.1~16μg/kg之间。结论该方法前处理操作快速简单，能够有效净化样品，满足玉米中有机氯和拟除虫菊酯农药的日常检测和监管工作，适用于大批次样品的定性定量分析。