气相色谱-串联质谱法测定茶叶中88种农药残留量

采用气相色谱-串联质谱(GC-MS/MS)分析技术,建立了高灵敏度检测茶叶中88种农药残留量的方法。目标化合物经加速溶剂萃取(ASE), Carb/NH2净化小柱净化,乙腈-甲苯(3:1, v/v)洗脱,采用GC-MS/MS测定。对方法的准确性、精密度、线性范围、最低检出限(LOD)和定量限(LOQ)进行了测试。其中87.5%的农药在低水平(6.4 μg/kg)的加标回收率为70%～100%; 87.5%的农药的相对标准偏差(RSD)小于15%。每个化合物均采用灵敏度最高的离子对进行定量,并采用空白茶叶基质配制标准工作液。LOQ以10倍信噪比(S/N=10)计算,86.4%农药的LOQ值低于10 μg/kg。该方法灵敏度高、准确、可靠,适用于绿茶、乌龙茶、红茶以及普洱茶中多种农药残留量的检测。

Determination of 88 pesticide residues in tea using gas chromatography-tandem mass spectrometry

A multi-residue method for the determination of 88 pesticides in tea using gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed. The target compounds were extracted with acetonitrile by accelerated solvent extraction (ASE), and the extracts were cleaned up by solid phase extraction (SPE) with a Carbon/NH2 cartridge and eluted with acetonitrile-toluene (3:1, v/v) before the identification and quantification of the residues by GC-MS/MS. Performance characteristics, such as accuracy, precision, linear range, limits of detection (LODs) and limits of quantification (LOQs), for each pesticide were determined. At low concentration level spiked (6.4 microg/kg), the average recoveries were in the range of 70%-100% for 87.5% analytes and the relative standard deviations (RSDs) were lower than 15% for 87.5% analytes. The quantification of analytes was carried out using the most sensitive transition for every compound and by matrix-matched standards calibration. The LOQs (S/N = 10) were less than 10 microg/kg for 86.4% analytes. The method is sensitive, accurate, reliable and suitable for the simultaneous determination of multi-residue pesticides in green tea, Woolong tea, black tea and Puer tea.