微波消解-电感耦合等离子体质谱法同时测定土壤中4种重金属元素

摘要

The samples were first treated by microwave digestion of nitric acid hydrochloric acid and hydrofluoric acid system,and then four heavy metal elements lead,copper,chromium and cadmium in soil were determined by ICP-MS simultaneously.The experimental conditions for treating and analyzing samples were optimized;in the mass spectrum measurement,indium,bismuth,germanium elements were used as internal standard element for the correction of matrix effect and the signal drift.The accuracy of the method was confirmed by the recoveries of standard additions and standard material.The results showed that the detection limits were 0.010、0.020、0.050、0.005 μg/L,the recoveries were 98％～106％、97％～112％、94％～118％ and 98％～104％,for lead,copper,chromium and cadmium,respectively.The method was used for the determination of lead,copper,chromium and cadmium in different soil standard materials;results were in the standard value range,and the relative standard deviations (RSDs) were 0.5％～2.5％.This method has been proved to be good stability,high precision,easy operation and low cost,can be applied to determine lead,copper,chromium and cadmium in a large number of soil samples synchronously.%采用硝酸-盐酸-氢氟酸作消解体系,以微波消解的方法处理土壤样品,利用ICP-MS同时测定土壤样品中的4种重金属元素(铅、铜、铬、镉).设定了最佳的样品前处理条件和仪器测定条件,在进行质谱测定时,采用In、Bi、Ge元素作为校正基体效应与信号漂移的内标元素.依据国家标准参考物质并通过加标回收试验,对方法进行了验证.结果表明:该方法所得重金属元素铅、铜、铬、镉的检出限分别为0.010、0.020、0.050、0.005 μg/L,加标回收率分别为98％～106％、97％～112％、94％～118％和98％～104％;测定不同土壤标准物质,铅、铜、铬、镉测定结果均在标准值允差范围内,相对标准偏差(RSD)介于0.5 ％～2.5％.说明该方法稳定性好、精密度高、操作简便、成本低,适用于大量土壤样品4种重金属元素(铅、铜、铬、镉)的同时测定.