气相色谱-负化学离子源质谱法测定含硫蔬菜中残留的14种农药

建立了含硫蔬菜(大葱、大蒜、蒜薹及韭菜等)中14种农药残留的气相色谱-负化学离子源质谱(GC-NCI/MS)检测方法。样品先采用微波加热处理除去大部分的含硫干扰物,然后用乙腈均质提取,提取液用凝胶渗透色谱(GPC)和N-丙基乙二胺(PSA)固相萃取小柱净化后用GC-NCI/MS在选择离子监测模式下测定。在50 μg/kg加标水平下回收率为49.2%～113.1%,相对标准偏差为1.42%～8.70%,检出限(以3倍信噪比计)为0.5～10.0 μg/kg。方法的选择性好,抗干扰能力强,能消除复杂基质带来的干扰,适合于含硫蔬菜中农药残留的确证分析。

Determination of 14 pesticide residues in sulfur-containing vegetables by gas chromatography-negative chemical ionization mass spectrometry

A gas chromatography-negative chemical ionization mass spectrometric (GC-NCI/MS) method has been developed for analyzing 14 pesticide residues in sulfur-containing vegetables (scallion, garlic, garlic bolt, leek, etc.). The samples were first heated in a microwave oven to eliminate most of the sulfur-containing interfering impurities and then extracted with acetonitrile. The extracts were further cleaned-up by gel permeation chromatography (GPC) and a primary-secondary amine (PSA) cartridge. The target analytes were determined using GC-NCI/MS in the selected ion monitoring (SIM) mode. The recoveries of all the pesticides (at spiked level of 50 μg/kg) were from 49.2% to 113.1% with the relative standard deviations between 1.42% and 8.70%. The detection limits (S/N=3) were in the range of 0.5-10.0 μg/kg. The method is selective without interference and suitable for the determination and confirmation of pesticides in the sulfur-containing vegetables.