应用ICP-MS、AFS、GF-AAS测定食品中As、Cd、Hg、Pb方法的对比研究

Method Comparison to Determination of As,Cd,Hg and Pb in Food by ICP-MS,AFS,GF-AAS

应用ICP-MS法测定食品中的As、Cd、Hg、Pb,AFS法测定As、Hg,GF-AAS法测定Cd、Pb,并对3种测定方法进行对比研究。采用微波消解法作为ICP-MS法的样品前处理方法,湿式消解法作为AFS、GF-AAS法的前处理方法。通过优化消解条件,优化ICP-MS、AFS及GF-AAS仪器测定工作条件,选择适宜内标元素、EPA200.8标准干扰校正方程、硫脲-抗坏血酸掩蔽剂、硝酸镁-硝酸钯混合基体改进剂等办法,利用小麦粉(GBW08503b)和大米粉(GBW10010)国家标准物质验证各方法的准确度与可靠性。测定值均在标准值允许范围内,食品试样比对测定结果相对偏差均小于20%。ICP-MS法线性动态范围宽,不必稀释样品,适合批量样品多元素同时分析,但仪器昂贵、实验成本相对较高;AFS、GF-AAS法是单一元素分析,保证了测定结果准确、可靠,但由于线性范围窄,部分样品需要稀释,分析周期较长。

As,Cd, Hg, Pb were detected by ICP-MS, and then As, Hg were detected by AFS, Cd, Pb were detected by AAS respectively. The comparison of 3 methods was studied. Microwave-digestion and wet digestion was adopted as pre-digestion method in ICP-MS and AFS, GF-AAS. By improving conditions of degistion, choosing internal elements and EPA200.8 interference calibration equation, using thiourea-ascorbic acid as masking agent and HNO3-Pd（HNO3）2 as amelioration agent, using CRM wheat flour（GBW08503b） and rice flour （GBW10010）, the accuracy and reliability of the method was verified. Determination results of elements are in the range which is permitted. The relative deviation of food samples is less than 20%. ICP-MS method has wide dynamic range, do not have to dilute the sample, it is suitable for a lot of samples and multi-element analysis at the same time, but it is expensive and relatively high cost. The measurement of the element by AFS and GF-AAS is one by one to ensure that the results are accurate and reliable, but because of the narrow linear range some samples have to be diluted, they have longer determination period and wide popularity.