Hydrogen catalytic waves for the polarographic determination of 2-mercaptobenzothiazole in the presence of cobalt(II)

Abstract

2-Mercaptobenzothiazole (MBT) is electrochemically inactive, but in complex combination with cobalt it forms a hydrogen catalytic wave, controlled by the kinetics of a protonation-deprotonation reaction. This wave has a surface character and can be used for analytical purposes in the determination of MBT with very high sensitivity (1 × 10^–6–1 × 10^–5M) in soluble samples or in solutions in a water-solvent mixture. The main parameters affecting this wave were studied, i.e., cobalt, ammonium chloride, ammonia and acetic acid concentrations, ionic strength and solvent effect. A mechanism for the interpretation of both chemical and electron transfer reactions is proposed. Conditions suitable for analytical applications and real systems are described.