样品的消解方法对定量分析重金属元素的影响

为了研究不同消解方法对土壤样品中重金属元素测定的影响,分别采用电热板消解、高压罐密闭消解和微波消解3种方法对土壤标准样品(GBW07440)进行前处理;在电感耦合等离子体质谱(ICP-MS)优化条件下,测定了3种消解方法中5种重金属元素(Cr、Cu、Zn、Cd及Pb)含量,进而建立一种消解-ICP-MS检测土壤中重金属元素含量的最佳方法。结果表明:微波消解最彻底且消解液澄清,电热板和高压罐消解剩余残渣均较多;3种消解方法的检出限均能达到μg/L级或者更低,但是微波消解法的检出限最低。5种元素标准曲线线性关系较好(相关系数r>0.999 90),RSDmax(Cr、Cd、Pb)

Effect of Digestion Methods on Quantitative Analysis of Heavy Metal Elements

In order to investigate the effects of three digestion methods(platen heating digestion,high pressure closed-vessel digestion and microwave digestion) on analysis of Cr,Cu,Zn,Cd and Pb in the digestion,Cr,Cu,Zn,Cd and Pb in the digestons of the national standard reference material(GBW07440) digested respectively with three methods above were analyzed by ICP-MS under its optimized model to establish a best method for determining and analyzing a variety of heavy metals in soil.The results suggested that microwave digestion was a most complete method and its digestion solution was most clarifying,but the residue by platen heating digestion and pressure close-vessel digestion remained more than microwave digestion.Detection limits of three methods were up to level of μg/L or lower level.However,the level of microwave digestion was lowest.Correlative coefficient of the calibration curves was over 0.999 90 by using ICP-MS determination of five types of elements.Maximum RSD of Cr,Cd and Pb was lower than that of Cu and Zn.The sensitivity and accuracy of ICP-MS were satisfied.Basically,testing value of three methods brought into correspondence with standard value in certified reference material.In conclusion,the method of microwave digestion was more first recommended to digest soil heavy metals.