断续流动在线分离富集-蒸气发生原子荧光光谱法测定复杂环境样品中痕量镉  

Intermittent Flow Injection On-line Pre-concentration and Determination of Ultra-trace Cadmium in Environmental Samples by Vapour Generation-Non-dispersive Atomic Fluorescence Spectrometry

作　　者：李中玺[1] 周丽萍[1] 

机构地区：[1]西北有色地质研究院,陕西西安710054

出　　处：《岩矿测试》2006年第3期233-238,共6页Rock and Mineral Analysis

摘　　要：用D201阴离子交换树脂富集样品中的痕量Cd,使Cd与共存干扰元素Cu、N i、Pb、Zn有效分离,消除了这些元素对镉蒸气发生的干扰,从而建立了断续流动在线分离富集-蒸气发生原子荧光光谱法测定复杂环境样品中痕量Cd的分析方法。方法的检出限为3 ng/L(3σ);测定精密度(RSD)为1.9%(对1μg/L Cd,n=11)。用该方法对国家一级标准物质(土壤、水系沉积物和岩石)中的痕量镉进行了测定,结果与标准值相符。A method of intermittent flow injection on-line pre-concentration and vapor generation coupled with non-dispersive atomic fluorescence spectrometry for the determination of ultra-trace amounts of cadmium in environmental samples was developed. Digested sample in O. 24 mol/L of hydrochloric acid was propelled through an anion-exchange resin （D201,80 mesh） column, where cadmium was retained and separated from coexisting elements. Elution was accomplished with O. 42 mol/L of ammonia and on-line measurements by AFS was carried out after acidity adjusting by adding 0.60 mol/L of hydrochloric acid and hydride generation of cadmium by reaction with potassium tetrahydroborate. The effects of main possible interfering ions on the generation of the volatile species were investigated. Large amounts of the common coexisting ions, such as copper, lead, nickel, zinc, cobalt and hydride-forming elements, had no significant interference on the determination of cadmium by HG-AFS after on-line matrix separation. Under the optimized conditions, the detection limit for Cd is 3 ng/L （3σ） and the precision of 1.9%RSD （n = 11） for the sample with 1 μg/L of Cd. The method has been successfully applied to the determination of cadmium in a series of national geological and environmental reference materials and the results are in good agreement with the certified values.

关 键 词：原子荧光光谱法 断续流动注射 在线富集 蒸气发生 镉 环境样品 

分 类 号：O657.31[理学—分析化学] O614.242[理学—化学]