Anion-exchange preconcentration-spectrophotometric determination of traces of copper in natural water samples

Abstract

A preconcentration-spectrophotometric determination of copper in sea and fresh water samples is described. After the sample is treated with permanganate, copper is allowed to enrich on a strongly basic anion-exchange column (Amberlite GG 400 in the chloride form; ɸ 0 1.0X4.5 cm) from 2 1 of acidified, heated sample water (40�°C, 0.01 M in HC1) in the presence of 0.01 M ascorbic acid. To enhance the adsorption the fresh water is made saline before sorption by adding sodium chloride to yield ca. 0.5 M concentration. Copper sorbed on the column can be stripped by elution with 20 ml of 1 M nitric acid. Copper is then determined spectrophotometrically with diethyldithiocarbamate. This combined method is sensitive to as low as 2X10-10 M of copper in 21 sample. Cadmium, nickel, manganese(II), lead, zinc, iron(III), cobalt, mercury(II) and silver do not interfere in the presence of even 100 times as much as their contents in seawater samples. The precision (rsd) of 3~7% at a copper level of 0.4~0.8 (μg/l can be obtained. © 1993, The Japan Society for Analytical Chemistry. All rights reserved.