全自动石墨消解-电感耦合等离子体质谱法同时测定食品中铜和铅

A study on the determination of copper and lead in food by automatic graphite digestion-inductively coupled plasma mass spectrometry

目的建立食品中铜和铅的全自动石墨消解-电感耦合等离子体质谱(ICP-MS)的分析方法。方法以Ge和Bi作内标,采用碰撞反应池模式,分别用全自动石墨消解和微波消解处理样品,用ICP-MS测定,并从检出限、准确度、加标回收率和精密度4个方面与微波消解-ICP-MS法比较。结果全自动石墨消解-ICP-MS法测定铜和铅2种元素的标准曲线相关系数均≥0.9998,检出限均<1.0μg/L,铜加标回收率均在99%~115%,铅加标回收率均在96%~105%,RSD均<1.5%,测定标准样品(GBW10015)时其测定值与标准值吻合。将全自动石墨消解-ICP-MS法和微波消解-ICP-MS法测定标准样品的结果进行配对t检验,二者铅的测定结果差异有统计学意义,前者的测定值更接近标准参考值。结论全自动石墨消解-ICP-MS法优于微波消解-ICP-MS法,是一种准确高效、安全便捷,可用于大批量食品样品中铜和铅检测的方法。

Objective To establish a method for the determination of copper and lead in food by automatic graphite digestion-inductively coupled plasma mass spectrometry(ICP-MS).Methods Using Ge and Bi as internal standard elements and KED as detection model,the samples were digested by automatic graphite digestion instrument and microwave digestion instrument respectively,and then the copper and lead in samples were determined by ICP-MS.The two methods were compared in four aspects,including detection limit,accuracy,standard recovery and precision.Results The correlation coefficients of the method were greater than 0.9998,the detection limit for both the elements were smaller than 1.0 g/L,and the recovery rates of copper were within 99%-115%,and the recovery rates of lead were within 96%-105%,with the RSDs smaller than 1.5%.The determination values of the certified sample(GBW10015)were in good agreement with the certified value by the method,and there was statistical significance on the differences in the determination results of lead by the two methods,but the determination value of the proposed method was closer to the reference value.Conclusion Automatic graphite digestion-ICP-MS is superior to microwave digestion-ICP-MS method,and it can be used for the detection of copper and lead in food samples.