固相萃取-气相色谱法测定猪肉中敌敌畏残留

Determination of dichlorvos in pork by solid phase extraction-gas chromatography

目的建立固相萃取-气相色谱法(gas chromatography,GC)测定猪肉中敌敌畏残留量的方法。方法猪肉样品中残留敌敌畏经过丙酮和二氯甲烷(4:3,V:V)提取后,经过水浴30℃旋转蒸发浓缩。浓缩液由丙酮和二氯甲烷(1:1,V:V)复溶后再由石墨化碳黑/氨基Carbon/NH_2(500 mg/500 mg/6 m L)双层固相萃取小柱进行净化处理,收集净化液再次经过30℃旋转蒸发浓缩,最后浓缩液经由岛津弱极性毛细管柱SH-RTX-5分离,通过磷滤光片的火焰光度检测器检测,采用外标法定量。结果敌敌畏在11 min内完全出峰,在0.2~1μg/mL范围内线性关系良好,相关系数r^2为0.9997,在20、50、100μg/kg加标水平下,回收率为100%~120%,相对标准偏差(relative standard deviation,RSD)为2.60%。结论该方法准确、灵敏、快速,具有稳定性强、重现性好等优点,并且能有效消除基质效应,适合猪肉样品中的敌敌畏残留量的测定。

extraction-gas Objective To chromatography dichloromethane （4：3, V： V） and establish a method for determination of dichlorvos in pork by solid phase （GC）. Method Dichlorvos residues in pork were extracted by acetone and then concentrated by rotary evaporation with 30 ℃ water bath. The concentrated solution was reconstituted with acetone and dichloromethane （1：1, V：V） and then purified by graphitized carbon black/amino （500 mg/500 mg/6 mL） double-layer solid-phase extraction cartridge. The purified solution was reconcentrated by rotary evaporation at 30℃. The concentrated solution was separated by shimadzu SH-RTX-5 weak polar capillary column, detected by a flame photometric detector of a phosphorus filter, and quantified by extemal standard method. Result The dichlorvos could be detected within 11 min and had good linearity in the range of 0.2-1 μg/mL, and the correlation coefficient r2 was 0.9997. The recoveries were 100%-120% with 3 spiked levels of 20, 50, and 100 μg/kg. The relative standard deviation （RSD） was 2.60% （n=6）. Conclusion This method is accurate, sensitive, rapid, stable, reproducible, and can effectively eliminate the matrix effect, which is suitable for the determination of dichlorvos residues in pork samples.