大体积进样气质联用法测定浓缩果蔬汁中农药的残留量

Determination of Pesticide Residues in Concentrated Fruit and Vegetable Juices by Gas Chromatography-Mass Spectrometry with Large-volume,Temperature-programmed Injection

建立了气相色谱-质谱同时检测果蔬汁中多类农药残留的方法。利用Agilent仪器的保留时间锁定功能(RTL)及相应的质谱农药库,建立了多类农药选择离子监测的分组时间窗,避免了仪器维护后农药保留时间烦琐的更新过程,保证了农药保留时间的重复性;探讨了具有溶剂排空模式的程序升温蒸发(PTV)对大体积进样的作用。通过对分流排空量、吹扫时间、PTV温度及其进样体积等PTV参数的优化,提高了检测灵敏度。通过同位素标记农药作为内标,GC-MS的定量可靠性得到改善。

A GC - MS procedure in the selected ion monitoring mode was developed for the determination of multiple pesticide residues in concentrated fruit and vegetable juices. Retention time locking （RTL） pesticide database was used to simplify the editing of SIM ion groups and eliminate the tedious retention time updating process upon instrument maintenance. Large volume injection of samples with a temperature-programmed vaporizer（PTV） system was investigated. Split vent flow, purge time, PTV system temperature, and maximum sample volume were optimized. In comparison with conventional methods, the detection limits were improved by one order of magnitude. By use of stable isotopically labeled pesticides （surrogate） as internal standards, the reliability of quantification in GC -MS analysis could be improved.