Subspeciation of nickel disulfide by carbon paste electrode voltammetry catalyzed by Ni2+

In subspeciation of sulfidic nickel, carbon paste electrode voltammetry was developed for the specific determination of Ni3S2 or NiS, but NiS2 was fou nd to be unreactive. Ni2+ in FH 7.2 acetate solution was able to catalyze N iS2 to undergo redox reactions. The cyclic voltammogram showed two anodic p eaks at -0.3 ansi +0.7 V and a cathodic peak at -0.6 V, The first anodic pe ak at -0.3 V and the cathodic peak were common among the three nickel sulfi des, but the second anodic peak at +0.7 V was unique to NiS2. This peak cur rent gave a linear dose response to NiS2 from 40 to 610 mug, with a correla tion coefficient of 0.994, and a detection limit of 40 mug.