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目的建立淡水鱼及养殖水体中共平面多氯联苯(co-PCBs)的固相支持液液萃取-气相色谱分析方法,为淡水鱼食品安全与养殖环境监控提供参考。方法鱼肉样品加水匀浆,水样过滤,分别用ChemElut多孔性硅藻土小柱吸附、二氯甲烷萃取、弗罗里硅土净化(水样不需净化),浓缩后正己烷定容。以DB-5MS石英毛细管柱(60m×0.25mm×0.1μm)为分离柱、GC-ECD检测。结果 12种co-PCBs色谱分离度R≥1.2,co-PCBs在4.3～138μg/L范围内线性关系良好(r≥0.99),检出限为0.16～0.44μg/L。淡水鱼中co-PCBs的最低检出量为1.6～4.4ng/kg;水样最低检出量为0.8～2.2ng/L。淡水鱼样加标平均回收率为76.3%～116.5%;水样加标平均回收率为75.9%～111.7%。相对标准偏差3.0%～18.2%。鱼体中检出PCB105。结论该法前处理简便快速,样品净化效果好。方法检出限低,准确度高,精密度好,满足淡水鱼及水体中痕量co-PCBs残留的分析要求。
Objective To establish a solid-liquid-liquid-liquid extraction-gas chromatography (GC-LC-MS) method for the determination of co-PCBs in freshwater fishes and aquaculture water so as to provide reference for the food safety and culture monitoring of freshwater fish. Methods The fish samples were homogenized with water and filtered through water. The samples were adsorbed on a ChemElut porous diatomaceous earth column, extracted with methylene chloride, and purified with Florisil (no water purification was required). After concentration, n-hexane was fixed. DB-5MS quartz capillary column (60m × 0.25mm × 0.1μm) as the separation column, GC-ECD detection. Results The chromatographic resolution of 12 co-PCBs was R≥1.2, and the linearity of co-PCBs was in the range of 4.3 ~ 138μg / L (r≥0.99). The detection limit was 0.16 ~ 0.44μg / L. The detection limit of co-PCBs in freshwater fish was 1.6 ~ 4.4ng / kg. The minimum detectable amount of water samples was 0.8 ~ 2.2ng / L. The average recovery rate of freshwater fish samples was 76.3% ~ 116.5%. The average recoveries of water samples were 75.9% ~ 111.7%. The relative standard deviation was 3.0% ~ 18.2%. PCB105 detected in the fish. Conclusion The pretreatment method is simple and rapid, and the sample purification effect is good. The method has the advantages of low detection limit, high accuracy and good precision to meet the analytical requirements of trace co-PCBs residues in freshwater fish and water.