气相色谱-质谱法测定多种农药残留

GC-MS Determination of Multi-Pesticide Residues

文中比较了气相色谱-负化学离子源-质谱法(GC-NCI-MS)与气相色谱-电子轰击离子源-质谱法(GC-EI-MS)分析多种农药残留量方法中的选择离子、质谱图、线性范围、检出限等指标,试验结果表明:GC-NCI-MS质谱图的碎片离子少,线性范围宽,11种农药除二嗪农及o,p-′DDT外,负化学离子源(NCI)的检出限都低于电子轰击离子源(EI)至少一个数量级;同一个样品,GC-NCI-MS的质谱图杂峰更少。若分子中含有易获得电子的基团,NCI源比EI源有更高的灵敏度和选择性。

It was shown by the results of a comparative study between GC-NCI-MS and GC-EI-MS on their Ⅰ analytical parameters of selected ions, mass spectrograms, linearity ranges and detection limits, that in their application to the determination of 11 pesticide residues in vegetables, besides diazion and o,p＇-DDT, less fragment ions, wider linearity ranges and much lower detection limits （at least 10 times lower） were obtained by GC-NCI-MS, and in addition, in the analysis of a same sample, less foreign peaks were observed. In the determination of pesticides in the molecules of which contained easy electron gaining functional groups, it was preferrable to used the GC-NCI-MS for better sensitivity and selectivity.