固相萃取–气相色谱–负化学源质谱法检测水果和蔬菜中的毒杀芬

采用改进的分散固相萃取(QuEchERs)法对样品进行前处理,建立水果和蔬菜中毒杀芬残留的气相色谱–负化学电离源质谱(GC–NCI–MS)检测方法。样品中的毒杀芬由正己烷提取,经吸附剂PSA+GCB净化,在GC–NCI–MS的选择离子扫描模式下进样分析。毒杀芬的色谱保留时间在12.5~18.0 min区间内,采用面积归一化法积分,外标法定量。毒杀芬质量浓度在0.050~2.000 mg/L范围内与色谱峰面积呈良好的线性关系,相关系数r=0.999 1。分别以蓝莓、黄桃、菠菜为基质,在0.025,0.050 mg/kg添加水平下,毒杀芬的回收率为107.2%~118.1%,测定结果的相对标准偏差为5.5%~8.8%(n=6),定量限为0.025 mg/kg。该方法检测快速,适用于水果和蔬菜中毒杀芬残留的日常检测。

Detection of Toxaphene in Fruits and Vegatables by Gas Chromatography-Negative Ion Mass Spectrometry With Dispersive Solid Phase Extraction

A method was developed for the determination of toxaphene residues in fruits and vegetables by gas chromatography–negative ion mass spectrometry (GC–NCI–MS) with modified QuEChERS sample preparation technique. The samples were extracted by hexane, and cleaned up by the dispersive solid–phase extraction sorbent PSA+GCB, finally analyzed by GC–NCI–MS with selected ion monitoring mode. The chromatographic retention time of toxaphene was from 12.5 to 18.0 min, and quantification was performed for toxaphene by using external standard method. The mass concentration of toxaphene was linearwith chromatographic peak area in the range of 0.050–2.000 mg/L, the correlation coefficient was 0.999 1. Blueberry, yellow peach and spinach were taken as matrix, toxaphene recovery was 107.2%–118.1%, and the relative standard deviation was 5.5%–8.8%(n=6) at spiking levels of 0.025, 0.050 mg/kg. The limit of quantification was 0.025 mg/kg. This method is rapid, and it can be used for routine determination of toxaphene residues in fruits and vegetables.