Determination of Cd in Sediment Samples by Flow Injection On-Line Anion Exchange Combined with Vapour Generation-Atomic Fluorescence Spectrometry
WANG Yi-zhuang1,QIU Hai-ou1*,TANG Zhi-yong1,GU Yan-sheng2,ZHANG Shu-qing1
1. Faculty of Materials Science and Chemical Engineering, China University of Geosciences, Wuhan 430074, China 2. Key Laboratory of Biogeology and Environmental Geology, Ministry of Education, China University of Geosciences, Wuhan 430074, China
Abstract：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·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·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 μg·L-1 with a detection limit of 0.058 μg·L-1. The RSD(5 μg·L-1,n=7) was 1.09%. The method was convenient, rapid and successfully validated by using national water sediment standard reference materials.
