Simultaneous determination of trace amounts of copper and lead in sediments by means of coprecipitation with zirconium hydroxide and differential pulse anodic stripping voltammetry.

Abstract

The simultaneous determination of copper and lead in sediments was achieved by means of coprecipitation with zirconium hydroxide and differential pulse anodic stripping voltammetry. Zirconium oxychloride solution containing 20mg zirconium was added to 50ml of sample solution containing 0.04g of sediments and the pH was adjusted to 8.8 with ammonia water (1:2). The precipitate was separated by filtration and then dissolved in 25ml of 4M hydrochloric acid. This solution was diluted to 50ml with distilled water. A portion of this solution was employed for the simultaneous determination of copper and lead. After bubbling nitrogen gas through the sample solution for 100 s, it was pre-electrolyzed for 100s. The potential was scanned from -0.70V to-0.10V vs. SCE for dissolution of copper and lead ions, which were determined from the peak current of the voltammogram. The results are as follows : (1) Zirconium hydroxide was the most effective collector of copper and laed when the pH was adjusted to 8.8 with ammonia water (1:2). (2) Bismuth(III) and arsenic(III) ions were found to interfere with the determination of copper. Thallium(I), tin(II) and arsenic(III) ions were found to interfere with the determination of lead. (3) This method is applicable to the simutaneous determination of trace amounts of copper and lead in river-bottom and sea floor sediments.