Estimation of thiamine hydrochloride and sulphite using charge transfer complex reaction

A new spectrophotometric method is used for estimating Thiamine hydrochloride in its pure form and pharmaceutical formulations, the present method depends on the reaction between Thiamine hydrochloride and chrome azurol S to form a red complex which exhibit maximum absorption at 510 nm, the addition of Sulphite to the resulted red complex is bleaching it and this step was used for the determination of Sulphite which is considered an attacker of Thiamine hydrochloride, therefore, this method was developed for determination of Thiamine hydrochloride in presence of Sulphite. The linearity of the proposed method was obeyed Beer’s law from 2 to 48 and 0.04 to 2.4 ppm for Thiamine hydrochloride and Sulphite respectively. Also, the method sensitivity was measured by molar absorptivity values 5.9×104 l.mol-1.cm-1 and 1.68×104 l.mol-1.cm-1 for Thiamine hydrochloride and Sulphite respectively. The present method accuracy (average recovery) 100.06% and 100.04% the precision (RSD) of the method is ±0.98 - ±1.27% and ±0.76 - ±1.47 of Thiamine hydrochloride and Sulphite respectively. This method was applied for the estimation of B1 and SO32- in pharmaceutical preparations and various water samples respectively.