摘要
介绍了微珠比色测定砷和镉的野外现场快速分析方法。微珠比色法测砷以钼酸铵为显色剂,在HNO3介质中,As(Ⅴ)与钼酸铵生成砷钼杂多酸,再用SnCl2还原生成砷钼蓝,硅、磷、锗干扰测定,可进行萃取加以分离,检出限为10ng,RSD(n=21)为13.3%。微珠比色法测镉以2-吡啶偶氮-2-萘酚为显色剂,锌、钴、铜等20多种离子干扰测定,可加入二安替比林甲烷-三氯甲烷进行萃取,加以分离,检出限5ng,加标回收率为100%～106%,RSD(n=21)为3.0%。对国家一级标准物质中痕量砷和镉进行测定,结果与标准值相符。
In this paper, two micro-bead colorimetric methods for determinations of arsenic and cadmium have been developed respectively. Arsenic is determined by using ammonium molybdate as chromogenic reagent. In HNO_(3) medium As (V) reacts with ammonium molybdate to form As-Mo heteropoly acids and then the product is reduced to arsenomolybdate by SnCl_(2). Interference from Si, P and Ge can be eliminated by solvent extraction and the detection limit for As by this method is 10 ng with precision of 13.3% RSD (n=21). Cadmium is determined by using pyridyl-azonaphthol as chromogenic reagent. Interference from over 20 coexisting elements(Zn, Cu, Co, etc.) can be removed by solvent extraction with DAM-CHCl_(3) and KCN. The recovery of standard addition for Cd is 100%～106% with precision of 3.0% RSD (n=21) and the detection limit for Cd is 5 ng. The methods have been applied to the determination of trace As and Cd in geological standard reference materials with satisfactory results.
出处
《岩矿测试》
CAS
CSCD
北大核心
2004年第1期25-29,共5页
Rock and Mineral Analysis
基金
国土资源部地质大调查项目(200002019017)
关键词
野外现场分析
微珠比色
砷
镉
analysis in the field
micro-bead colorimetry
arsenic
cadmium
