ICP-MS测定蔬菜样品中重金属元素的两种微波消解前处理方法

Two Microwave Digestion Pretreatment Methods for Determination of Heavy Metals in Vegetable Samples

微波消解法是处理生物样品的主要技术,但存在处理效率不高等问题还有待进一步研究。本文采用高压低通量(12位)和低压高通量(41位)微波消解法对蔬菜样品进行前处理,电感耦合等离子体质谱法(ICP-MS)测定砷、镉、铬、铜、镍、铅和锌,氢化物发生-冷原子荧光光谱法(HG-CAFS)测定汞。采用两种前处理方法消解标准物质GBW 10010(大米)和GBW 10014(圆白菜),ICP-MS的测定值与标准值基本吻合,全流程加标回收率为91.5%～103.8%;用于测定GBW 10010和GBW 10014,因GBW 10010中铬、铅、砷,GBW 10014中砷的含量较低,测定值与标准值的相对误差较大;其余元素的测定值与标准值基本相符,表明两种前处理方法均能满足分析要求。但在保证测定结果质量的前提下,低压高通量微波消解处理样品,试剂用量少,单次样品处理量大,更加适合大批量生物样品的前处理。

Microwave digestion technology is a relatively recent method for processing biological samples, but there are some problems, such as low efficiency, which require further study. As described in this paper, vegetables were decomposed by two different microwave digestion methods of high pressure low flux and low pressure high flux microwave digestion. The contents of As, Cd, Cr, Cu, Ni, Pb and Zn in the sample solutions were determined by Inductively Coupled Plasma-Mass Spectrometry （ICP-MS） , and contents of Hg by Hydride Generation-Cold Atomic Fluorescence Spectrometry （HG-CAFS）. As shown by the experimental results, the measured value of National Standard Reference Materials is in agreement with the certified values by the two different methods. The relative errors of the two methods were less than 21%, the relative standard deviation was less than 4% and the recovery ratios were 91.5% - 103.8%. Low pressure high flux microwave digestion method is a better method of sample dissolution for large quantities of biological sample analysis because it improves the efficiency of sample digestion.