GC-MS/MS法测定猪肉中二噁英及二噁英类多氯联苯

Determination of Dioxins and Dioxin-like Polychlorinated Biphenyls in Pork by Gas Chromatography-Tandem Mass Spectrometry

建立基于气相色谱-串联质谱(gas chromatography-tandem mass spectrometry,GC-MS/MS)仪器,采用稳定性同位素稀释法测定猪肉中二噁英及二噁英类多氯联苯。样品经索氏提取,酸化硅胶除脂。然后经过多层硅胶柱、碱性氧化铝柱和活性炭柱净化,分别收集含二噁英(dioxins,PCDD/Fs)和二噁英类多氯联苯(dioxin like polychlorinated biphenyls,DL-PCBs)的组分。最后经浓缩溶剂交换后供GC-MS/MS测定。从样品的除脂方式、脂肪含量对净化的影响、系统空白污染来源等方面进行探讨。结果发现,凝胶渗透色谱除脂对PCDD/Fs和DL-PCBs的回收率影响较大,酸化硅胶除脂更适合超痕量的二噁英类化合物的分析和检测。二噁英检测的系统空白污染主要来自于索氏提取仪。该方法中内标的回收率为45.3%~122.4%,相对标准偏差(relative standard deviation,RSD)为1.0%~14.7%;目标物的回收率为64.9%~118.8%,RSD为1.1%~14.7%,方法线性和检出限能够达到GB 5009.205—2013《食品中二噁英及其类似物毒性当量的测定》的相关要求,适用于猪肉样品中PCDD/Fs和DL-PCBs的测定。

A gas chromatography-tandem mass spectrometry(GC-MS/MS)with stable isotope dilution(SID)method was established for the determination of dioxins(PCDD/Fs)and dioxin like polychlorinated biphenyls(DL-PCBs)in pork.The sample was extracted by Soxhlet extraction,defatted using acidified silica gel,and purified by sequential chromatography on a multi-layer silica gel column,an alkaline alumina column and an activated carbon column.PCDD/Fs-and DL-PCBs-rich fractions were collected separately,concentrated and redissolved for GC-MS/MS analysis.The influence of defatting method and fat content on the purification efficiency was investigated,and the blank contamination source of the system was discussed.The results showed that gel permeation chromatography(GPC)degreasing had a great influence on the recovery of PCDD/Fs and DL-PCBs,and acidified silica gel degreasing was more suitable for the analysis and detection of ultra-trace dioxins.The major blank pollution source of the dioxin detection system was the Soxhlet extractor.The recoveries for internal standard were 45.3%–122.4%with relative standard deviation(RSD)of 1.0%–14.7%.The recoveries for the analytes were 64.9%–118.8%with RSD of 1.1%–14.7%.Both the linearity and limit of detection(LOD)met the requirements of the national standard of China GB 5009.205-2013.The proposed method is suitable for the determination of PCDD/Fs and DL-PCBs in actual pork samples.