农田土壤中的重金属含量的测定

Determination of heavy metals in farmland soil

针对土壤重金属前处理方法选择多,抉择难的问题,将常见的电热板消解、全自动石墨消解法、微波消解法进行对比。通过观察3种消解方法处理对4种金属元素测定结果的影响,确定3种消解方法的优缺点。试验结果表明:3种消解方法处理的土壤检出限均满足《全国土壤污染状况详查土壤样品分析测试方法技术规定》要求,且相对标准偏差均未超过10%。在3种消解方法中,微波消解法不易受外界干扰,检出限最优,消解4种元素的相对标准偏差基本小于2%,且均值都在标样标准值不确定范围内,性能最佳。但微波消解法需要配套赶酸器,成本较高,因此,需要根据具体情况选择。

In view of the problem that there are many choices and difficult choices for soil heavy metal pretreatment methods,the common electric heating plate digestion method,automatic graphite digestion method and microwave digestion method were compared.By observing the influence of three digestion methods on the determination results of five metal elements,the advantages and disadvantages of three digestion methods were determined.The specific conclusions are as follows:the detection limits of the three digestion methods meet the requirements of“technical regulations on analysis and test methods of soil samples for national soil pollution survey”,and the relative standard deviation is more than 10%;among the three digestion methods,the microwave digestion method is not easy to be interfered by the outside world,and the detection limit is the best,and the relative standard deviation of the five digestion elements is basically less than 2%,and the relative standard deviation is less than 5%.The results showed that the average value is within the uncertainty range of the standard value of the standard sample,and the performance is the best;however,the microwave digestion method needs to be equipped with acid driving device,and the cost is high,so it needs to be selected according to the specific situation.