固相萃取-气相色谱-电子捕获检测器测定蔬菜中11种有机磷农药残留

目的建立固相萃取-气相色谱-电子捕获检测器(gas chromatography-electron capture detector,GC-ECD)测定蔬菜中11种有机磷农药残留的方法。方法样品中残留的农药经乙腈提取,固相萃取小柱净化后注入气相色谱仪中,用GC-ECD同时测定11种有机磷类农药残留量。并与常用的气相色谱-火焰光度检测器(gas chromatography-flame photometric detector,GC-FPD)测定有机磷农药残留比较检出限。结果在西葫芦中添加农药浓度为0.025~0.20 mg/kg条件下,11种有机磷农药平均回收率为84.5%~103%;相对标准偏差为1.48%~4.34%;方法定量限为0.0004~0.034 mg/kg。ECD测定11种有机磷农药的检出限比用FPD测定要低很多。结论建立的方法具有操作简单、试剂用量少及准确度、精密度高等优点,同FPD相比,建立的ECD方法对11种农药有更高的灵敏度。

Determination of 11 kinds of organophosphorus pesticide residues in vegetables by gas chromatography-electron capture detector coupled with solid phase extraction

The method for determination of 11 organophophorus pesticide residues in vegetables was developed. Methods The sample was extracted by acetonitrile, cleaned by solid phase extract(SPE) and injected into the gas chromatograph for determination of 11 organophosphorus pesticide residues by gas chromatography-electron capture detector (GC-ECD). Results The average recoveries of 11 pesticides ranged from 84.5%~103%, and the relative standard deviations (RSDs) were 1.48%~4.34%. The limits of quantitation were 0.0004~0.034 mg/kg. Conclusions This method had the merits of simply, rapidty, high accuracy and precision. Comparison with the fire photometric detector(FPD) which used to determine the organophophorus pesticides, the ECD has better sensibility to 11 kinds of organophophorus pesticides.