摘要：为了考察食用油中7种指示性多氯联苯(PCBs)的残留情况,建立了食用油中痕量多氯联苯测定的双重净化-气相色谱法。以乙腈提取样品,提取液浓缩至干后用正己烷溶解,经浓硫酸、硅胶分散固相萃取双重净化后进行气相色谱分析,外标法定量。优化的色谱条件为:HP-5石英毛细管柱(30 m×0.32 mm×0.25 μm)程序升温分离,流速0.8 mL/min,进样量1.00 μL,电子捕获检测器检测。结果表明:在优化的条件下,7种多氯联苯在10~500 μg/L范围内线性良好,相关系数大于0.999,不同基质中的检出限(S/N=3)范围为1.8~8.9 μg/kg,定量限(S/N=10)范围为5.9~29.8 μg/kg。在橄榄油、花生油和棕榈油空白样品中添加10、20、100 μg/kg 3个水平的7种多氯联苯,其加标回收率范围为71.0%~105.5%,相对标准偏差(RSD)范围为4.0%~11.3%。该方法具有操作简便、快速、准确的特点,可用于植物油中指示性多氯联苯残留量的日常检测。

Abstract: To investigate the residues of seven indicator polychlorinated biphenyls (PCBs) in vegetable oils, a method was established for the determination of trace PCBs in vegetable oils by double clean-up coupled with gas chromatography (GC). After extracted with acetonitrile, the sample extract was concentrated to dryness followed by re-dissolving with hexane. And the solution was pretreated by adding concentrated sulfuric acid followed cleaned-up with silica gel in dispersive solid-phase extraction protocol, then analyzed by GC with external standard method. Under the optimized chromatographic conditions, the analysis was carried out with a capillary column (HP-5, 30 m×0.32 mm×0.25 μm) at a flow rate of 0.8 mL/min, and the sample volume was 1.00 μL. Monitoring with an electron-capture detector, all the target analytes were separated by temperature-programming of the column. Good linearities were obtained in the range of 10-500 μg/L for the seven indicator PCBs with the correlation coefficients greater than 0.999. For different matrices, the limits of detection (S/N=3) and limits of quantitation (S/N=10) were in the range of 1.8-8.9 μg/kg and 5.9-29.8 μg/kg, respectively. At three spiked levels of 10, 20 and 100 μg/kg of the seven indicator PCBs in olive oil, palm oil and peanut oil blank samples, the average recoveries ranged from 71.0% to 105.5% with the RSDs of 4.0%-11.3%. The method is simple, rapid and accurate, and can be used for the routine analysis of the indicator PCBs in vegetable oils.