气相色谱-串联质谱法测定葵花籽中28种农药残留
Determination of 28 pesticide residues in sunflower seeds by gas chromatography-tandem mass spectrometry

建立了气相色谱-串联质谱(GC-MS/MS)测定葵花籽中咯菌腈、氯氰菊酯、异丙甲草胺等28种农药残留的方法。样品经乙腈提取,凝胶渗透色谱(GPC)及固相萃取(SPE)净化,GCMS/MS测定,多反应监测模式(MRM)分析,外标法定量。结果表明:采用凝胶渗透色谱及固相萃取净化可有效排除大部分干扰成分;在0.01~0.5 mg/L范围内,28种农药的峰面积与对应的质量浓度间呈良好的线性关系,决定系数R2>0.994;在50、100和200 μg/kg 3个添加水平下,各农药的平均回收率在74%~120%之间,相对标准偏差在0.9%~9.5% (n=5)之间,定量限在0.2~7.6 μg/kg之间。该方法灵敏、准确、可靠,能满足农药残留检测的要求,可用于监测葵花籽生产过程中的农药残留。
A gas chromatography-tandem mass spectrometry (GC-MS/MS) method was developed for the determination of 28 pesticide (including fludioxonil, cypermethrin, metolachlor and etc.) residues in sunflower seeds. The samples were extracted with acetonitrile, purified with gel permeation chromatography (GPC) and solid-phase extraction (SPE). The analysis of the extracts was performed using tandem mass spectrometry under multiple reaction monitoring (MRM) mode. Matrix-matched calibration curve was used to qualify the residue concentrations with external standard method. The results showed that GPC and SPE purification could eliminate the interference constituents. Good linearity was obtained in the range of 0.01-0.5 mg/L for 28 pesticides with coefficients of determination greater than 0.994. The mean recoveries mostly ranged between 74% and 120% at the three spiked concentration levels (50, 100, 200 μg/kg), and the relative standard deviations were between 0.9% and 9.5% (n=5), the limits of quantification(LOQ) were in the range of 0.2-7.6 μg/kg. The method presented was sensitive, accurate and reliable. Therefore, it could meet the needs for the determination of pesticide residues, and could be used for monitoring the level of residues in the process of sunflower seeds production.