阳离子交换净化/气相色谱-质谱法与气相色谱法测定蔬菜水果中15种三唑类农药残留

采用离子交换净化法,建立了蔬菜水果中15种三唑类农药残留测定的前处理方法。样品用乙腈提取,加入氯化钠均质,离心分层后取部分乙腈层经溶剂转换后过阳离子交换柱净化,所得净化液经浓缩定容后供气相色谱仪(GC)和气相色谱-质谱仪(GC-MS)分析。气相色谱-质谱法采用选择离子扫描方式(SIM),外标法定量。结果表明,在最优条件下15种三唑类农药的定量下限(S/N≥10)均可达到0.01 mg/kg,在0.01、0.05、0.10 mg/kg三个加标水平下的回收率为68%~102%,相对标准偏差为2.4%~16.2%。实验特别考察了该净化方法在气相色谱-电子捕获检测器(ECD)上的适用性,发现各种蔬菜水果(包括葱属蔬菜)均可获得干扰极少的ECD谱图。方法简单、快速,适用于多种蔬菜水果中15种三唑类农药残留的测定。

Determination of 15 Triazole Pesticides in Vegetables and Fruits by Gas Chromatography and Gas Chromatography-Mass Spectrometry

A method was developed for the determination of 15 triazole pesticides in vegetables and fruits by gas chromatography(GC) and gas chromatography-mass spectrometry (GC-MS) with ion exchange column.The samples were pretreated quickly,then extracted with acetonitrile after sodium chloride homogenization,separated by liquid-liquid partition.The clear supernatant purified by solid phase extraction with ion exchange column was ready for GC-ECD and GC-MS analysis.Determinations were performed by using selected ion monitoring (SIM) mode,and external standard method was used for quantification.After optimizing the conditions for pretreatment and determination,the method was convenient and rapid.Under the optimal conditions,the quantitation limits of the method (S/N ≥ 10) were 0.01 mg/kg.The recoveries at spiked levels of 0.01,0.05,0.10 mg/kg were in the range of 68％-102％ with the relative standard deviations of 2.4％-16.2％.Besides,the pretreatment has a good purification effect in GC-ECD chromatogram.The method is easy,rapid and sensitive,and could meet the requirements for the analysis of 15 triazole pesticides in vegetables and fruits.