GC-MS/MS法测定水果、蔬菜中敌草快的残留量

Determination of Diquat Dibromide Residues in Fruits and Vegetables by Gas Chromatography-Tandem Mass Spectrometry

建立水果、蔬菜中敌草快残留量的气相色谱-串联质谱(GC-MS/MS)检测方法,比较硼氢化钠、硼氢化钾2种衍生化试剂用于敌草快衍生化反应的差异。果蔬样品经纯净水超声提取,中性氧化铝净化,硼氢化钠或硼氢化钾衍生,采用GC-MS/MS多反应监测模式分析,外标法定量。结果表明,采用优化后条件,敌草快在0.01~1.00 mg/kg定量范围内,线性关系良好,相关系数均在0.99以上。选取10种不同基质的果蔬样品,在空白样品中添加浓度为0.02, 0.05和0.10 mg/kg不同水平的敌草快标准溶液,敌草快的平均回收率为71.3%~95.3%,相对标准偏差小于6.4%。敌草快经2种衍生化试剂衍生后响应接近,采用硼氢化钠或硼氢化钾均可用于敌草快的衍生化反应。敌草快的检出限(S/N=3)和定量限(S/N=10)分别为2.1μg/kg和6.4μg/kg。方法操作简便、灵敏、准确、分析速度快、抗干扰能力强,适用于果蔬中敌草快残留量的定性、定量分析。

A gas chromatography-tandem mass spectrometry(GC-MS/MS) was established for the determination of diquat dibromide residues in fruits and vegetables. Sodium borohydride and potassium borohydride used as the derivatization reagents for diquat dibromide were reported. Samples of fruits and vegetables were extracted with pure water, and then a cleanup step using neutral alumina was applied. The purified extract was derived by sodium borohydride and potassium borohydride, and quantified by external standard method in multiple reactions monitoring mode(MRM). Under the optimized condition, the target concentrations and peak areas were linearly correlated in the range of 0.01-1.00 mg/kg, and the correlation coefficients were greater than 0.99. Recovery studies were carried out on spiked matrices(ten different fruits and vegetables) with azocyclotin, cyhexatin and fenbutatin oxide at spiking levels of 0.02, 0.05 and 0.10 mg/kg. The mean recoveries were 71.3%-95.3%, with relative standard deviations less than 6.4%. The response for the derivatives of sodium borohydride and potassium borohydride by these two derivatization reagents were close. The limits of detection(LODs, S/N=3) and limits of quantification(LOQs, S/N=10) was 2.1 μg/kg and 6.4 μg/kg. The method was simple, sensitive, accurate, fast in analysis, powerful anti-jamming performance, and was suitable for qualitative and quantitative analysis of diquat dibromide residues in fruits and vegetables.