四种酸体系对微波酸溶-电感耦合等离子体质谱法测定固体废物中16种金属元素含量的影响

Influence of Four Kinds of Acid Systems on Determination of 16 Metal Elements in Solid Wastes by ICP-MS with Microwave Acid Digestion

微波酸溶消解方法是测定固体废物中金属元素最主要的前处理方法,消解时使用不同的酸体系对测定结果有较大的影响。本文以国家土壤标准样品、固体废物标准样品和固体废物实际样品为材料,比较了在硝酸-盐酸、硝酸-氢氟酸、硝酸-盐酸-双氧水、硝酸-盐酸-氢氟酸-双氧水4种酸体系下,16种金属元素测定结果的差异以及在硝酸-盐酸和硝酸-盐酸-氢氟酸-双氧水酸体系下各元素的精密度和准确度。研究表明：一些土壤基体中加入氢氟酸能使Mo和Sb的回收率提高40%左右,固体废物样品中只有Sb的回收率能提高33%~50%。对于含氢氟酸的酸消解体系,改变硝酸和盐酸的比例,其测定结果没有明显差异;对于元素含量相差悬殊的铬渣样品,由于空间电荷效应,高浓度的Cr对V的测定有抑制作用。从方法的准确度和精密度来看,硝酸-氢氟酸-盐酸-双氧水的消解效果最好。

Microwave acid digestion is the most important pretreatment method for the determination of metal elements in solid wastes by Inductively Coupled Plasma-Mass Spectrometry（ ICP-MS）. Different acid systems have significant influences on the results. In this study,comparative analysis results of 16 metal elements in national soil standard sample,solid waste standard samples and solid waste actual samples were carried out in four different acid systems of HNO_3-HCl,HNO_3-HF,HNO_3-HCl-H_2O_2 and HNO_3-HF-HCl-H_2O_2. The precision and accuracy of different elemental determination in HNO_3-HCl and HNO_3-HF-HCl-H_2O_2 systems were also evaluated. Results show that adding HF can improve the 40% recovery of Mo and Sb in soil matrix. Recovery of Sb in solid waste can improve 33%- 50% by adding HF. In the system containing HF acid,the varied ratios of HNO_3 and HCl show no significant effect in elemental determination. However,for the Cr slag samples,the high concentration of Cr inhibited the V signals because of the space charge effect. In terms of precision and accuracy,the HNO_3-HF-HClH_2O_2 is considered as the best acid system for determination of metal elements in solid waste.