Trace and selective determination of cobalt(II) in water and saltudsamples using cathodic adsorptive stripping voltammetryudin the presence of Pyrogallol Red

摘要

Abstract: A sensitive and selective procedure is presented for the voltammetricuddetermination of cobalt. The procedure involves an adsorptive accumulation ofudcobalt Pyrogallol Red (PGR) complex on a stationary mercury drop electrode,udfollowed by cathodic stripping voltammetry measurement of the reductionudcurrent of the adsorbed complex at –1.17 V (vs. Ag/AgCl). The optimum conditionsudfor the determination of cobalt include pH 11.0, 35 μM Pyrogallol Red,udan accumulation potential of –0.9 V (vs. Ag/AgCl) and scan rate 80 mV s-1.udThe peak current is proportional to the concentration of cobalt over the concentrationudrange 5.0 to 280 ng mL-1 with a detection limit of 1 ng mL-1 and anudaccumulation time of 140 s. The method was applied to the determination ofudcobalt in analytical grade NaCl and water samples.