THE DETERMINATION OF COBALT IN WATER SAMPLES BY CATHODIC STRIPPING VOLTAMMETRY

An analytical procedure for determination of cobalt using cathodic str ipping voltammetry with adsorptive preconcentration of complex species with alpha-benzyldioxime (alpha-BD) on a hanging mercury drop electro de was applied for sea and tap water analysis. The optimized condition s include: pH 9 (0.1 mol l(-1) ammonia buffer), alpha-BD concentration 2.6x10(-5)mol l(-1) and nitrite concentration 0.1 mol l(-1). The cata lytic effect of nitrite ions is responsible for high sensitivity of th e method. The limit of detection for cobalt in sea water is below 2 ng l(-1) ata deposition time of 30 s. The total cobalt concentration, de termined after UV irradiation of the sample at pH 2, is the same as wi thout UV irradiation. The square-wave CSV with background subtraction was succesfully applied for determination of cobalt traces in the non- deaerated sea water from Ati antic near Gran Canaria.