顶空固相微萃取-气相色谱-质谱法测定蔬菜及水果中15种农药残留量

GC-MS Determination of Residual Amounts of Pesticides in Vegetables and Fruits with Head-Space Solid-Phase Microextraction

应用顶空固相微萃取-气相色谱-质谱法测定蔬菜及水果中15种农药的残留量。样品用顶空-固相微萃取进行前处理。经优化的试验条件:1采用100μm聚二甲基硅氧烷萃取头;2离子浓度:样品匀浆液中含(w)30%氯化钠;3萃取温度为70℃±1℃;4萃取时间为30min。在气相色谱分离中用HP-5MS色谱柱,在质谱分析中采用全扫描和选择离子监测模式。15种农药的质量浓度均在0.05~1.0mg·L-1范围内与其峰面积呈线性关系。方法的检出限(3S/N)在0.02~0.10μg·kg-1之间。以2种果品作基体,在0.05,0.2,0.5mg·kg-1 3个浓度水平进行加标回收试验,测得回收率在71.0%~96.0%之间,测定值的相对标准偏差(n=5)在0.5%~9.8%之间。

HS-SPME-GC-MS was applied to the determination of residual amounts of 15 pesticides in vegetables and fruits.The optimized conditions found were as follows:1100μm PDMS micro-extractor was used;2concentration of salt ion:30%(w)NaCl;3temperature of extraction:70 ℃±1 ℃;4time of extraction:30min.HP-5MS column was used for GC separation,and mode of full-scanning as well as selected ion monitoring were adopted in MS determination.Linear relationships between values of peak area and mass concentration of the15 pesticides were kept in the same range of 0.05-1.0mg·L-1,with detection limits(3S/N)in the range of0.02-0.10μg·kg-1.Tests for recovery were made using 2fruit samples as matrixes by standard addition method at 3concentration levels of 0.05,0.2,0.5mg·kg-1,giving values of recovery and RSD′s(n=5)in the ranges of71.0%-96.0%and 0.5%-9.8%respectively.