Rate of Oxidation of Thiamine by Hg(II) in Alkaline Medium

Abstract

A differential kinetic spectrophotometric method is proposed for studying
the rate of oxidation of thiamine, TM (vitamin B₁) by mercury(lI) in basic
medium (pH = 12.5). The reaction has been studied in the range of 277.7 K to
320.5 K. The concentration of thiamine used: 0.35 x 10^-5 M, 0.70 X 10^-5 M
and 1.40 x 10^-5 M. The concentrations of OH^- and Hg(Il) were kept constant
by using 2 M NaOH and 2.0 x 10^-3 M Hg(lI). Under these conditions, the only
reaction product detected was thiochrome (TC). The initial rate was followed
by recording the rate of formation of TC at  λ = 350 nm for the first 20 seconds.
Different kinetic parameters have been measured under reaction conditions.