生物样品中手性多氯联苯对映体的分离测定

摘要

建立了生物样品中12种手性多氯联苯(CB 45、CB 84、CB 91、CB 95、CB 131、CB 132、CB 136、CB 149、CB 171、CB 174、CB 176和CB 183)对映体的分离测定方法.样品经索氏抽提,抽提液依次经凝胶渗透色谱柱、氧化铝硅胶复合柱和弗罗里硅土柱净化和分离后,采用气相色谱-质谱联用仪( GC - EI/MS)进行定性定量分析,计算目标化合物的对映体分数(EF).结果显示,鱼肉样品中共检出10种手性PCBs,其分离度在0.5～2.1之间.样品平行样中EF值的相对标准偏差(RSD)均小于2％.利用两根不同手性色谱柱分离CB 84、CB 91和CB 174的手性对映体,其EF值的RSD分别为1.2％、0.2％和0.2％,表明方法的准确度较高.%A method was developed for the separation and determination of 12 chiral polychlorinated biphenyls(PCBs), i.e. CB 45, CB 84, CB 91, CB 95, CB 131, CB 132, CB 136, CB 149, CB 171, CB 174, CB 176 and CB 183, in biological samples. The target chemicals were Soxhlet extracted , cleaned up by gel permeation chromatography and multi-layer silica alumina column, and were further fractioned with a Florisil column. The chiral PCBs were identified and quantified by gas chromatography - mass spectrometry with electron impact ion source (GC -EI/MS). The peak resolutions of these chiral congeners ranged from 0. 5 to 2. 1. The relative standard deviations of the calculated enantiomeric fractions ( EFs) in triplicates were less than 2% . The enantiomers of CBs 84, CB 91 and CB 174 in the standard solutions were separated by two different chiral columns. There was a slight discrepancy in the calculated EFs between the two columns, with relative standard deviations of 1. 2% , 0. 2% and 0. 2% for CB 84, CB 91 and CB 174, respectively, suggesting the high degree of accuracy and efficiency of the established method.a