DETERMINATION OF COBALT BY ADSORPTIVE STRIPPING VOLTAMMETRY USING COBALT(II)-NIOXIME-NITRITE CATALYTIC-SYSTEM

A differential pulse adsorptive voltammetric method for the cobalt determination with detection limit of 1.2x10- 10 M (100 sec preconcentration) is proposed. The preconcentration of Co(ll)-nioxime complex during the adsorption step and utilization of catalytic effect during the reduction of Co(II)-nioxime complex provides a great enhancement of cobalt voltammetric response. The ammonia buffer solution containing nioxime and nitrite is suitable for the adsorptive voltammetric determination of nanomolar cobalt concentrations in the presence of 1000-fold excess of nickel and 10 000-fold excess of zinc_. © 1990, Taylor & Francis Group, LLC. All rights reserved.