An Electrochemical Study of Thiamine Disulphide on Mercury

Abstract

The electroreduction of thiamine disulphide was studied by using dc, dp, np and rp polarography in aqueous buffered media. Depending on thiamine disulphide concentration, pH, temperature and drop time, up to four waves (peaks), I-IV, were obtained. Waves 11 and 111 are characterized as adsorption post-waves and wave I corresponds to the "main wave", the latter being the only wave previously described in the literature. Involvement of the product of the charge transfer reaction (thiolic form of thiamine) in an irreversible chemical reaction was detected. Taking into account additional recent kinetic studies on the structural transformations of thiamine, a mechanism for the electroreduction of thiamine disulphide that explains the observed dependence of E,,, of I on pH is proposed.