流动注射在线离子交换分离-蒸气发生原子荧光测定沉积物中的镉

提出了Co2 -1,10-二氮杂菲作为增感剂,流动法测定水系沉积物中超痕量镉的分析方法.设计了流动注射在线离子交换分离富集流路,优化了仪器各项操作参数及各项化学条件.方法在2.0 mol·L-1盐酸介质中,以717型强碱性阴离子交换树脂为吸附剂富集镉,铜、铅因不被吸附而与镉分离,然后用0.5 mol·L-1硝酸洗脱镉,洗脱液直接经断续流动蒸气发生原子荧光光谱法进行测定.实验结果表明,方法操作简便、快速,能有效地富集镉和消除大量铜、铅对测定镉的干扰,且Co2 和1,10-二氮杂菲能极大的提高镉的蒸气发生效率.该方法检出限(3δ)为0.058μg·L-1,相对标准偏差(RSD)为1.09%(5 μg·L-1,n=7),线性范围0～12 μg·L-1.经国家一级水系沉积物标准物质分析验证,分析结果可靠.

Determination of Cd in Sediment Samples by Flow Injection On-Line Anion Exchange Combined with Vapour Generation-Atomic Fluorescence Spectrometry

In the present work, a method was developed for the determination of ultra-trace levels of Cd in sediment samples by atomic fluorescence spectrometry (AFS). A flow injection on-line separation and preconcentration technique coupled with an intermittent injection vapor generation technique was employed in the study. The instrument operating parameters and chemical conditions were optimized. In a 2.0 mol x L(-1) HCl solution, Cd (II) was adsorbed on 717-strong alkaline anion exchange resin, while Cu (II) and Pb (II) passed throngh. Then Cd (II) was eluted by 0.5 mol x L(-1) HNO3. The eluting solution was determined directly by intermittent injection vapor generation atomic fluorescence spectrometry. It was showed that Cd (II) can be preconcentrated effectively and the interference can be completely eliminated by this improved method. The Cd atomic vapor generation efficiency could be greatly enhanced in the presence of Co (II) and 1, 10-phenanthroline. The linear range of the determination was 0-12 microg x L(-1) with a detection limit of 0.058 microg x L(-1). The RSD (5 microg x L(-1), n=7) was 1.09%. The method was convenient, rapid and successfully validated by using national water sediment standard reference materials.