Abstract
Naftazone (1,2-naphthoquinone-2-semicarbazone) undergoes a reversible two-electron transfer in both acidic and alkaline solutions and also gives rise at pH > 7 to an anodic wave attributed to the formation of a mercury derivative. Cathodic stripping voltammetry is proposed to determine the compound down to 5 × 10−9 M after accumulation of its mercury salt formed at -0.05V in a 0.05M sodium hydroxide solution. These results have been compared with those obtained by performing an adsorptive collection of the drug in a pH 3 sodium perchlorate solution. Concentrations ranging from 1 × 10−7 to 2 × 10−7M can be easily investigated, the detection limit being 7 × 10−11M. The influence of several operational parameters has also been considered.