Electrochemical Derivatization of Thiamine in a Flow Injection System-Application to Thiamine Analysis

A novel technique using on-line electrochemical derivatization of thiamine is described which can enhance considerably both the sensitivity and specificity of detection. Material injected is electrolyzed in a flow electrolytic cell which may induce a reaction yielding highly fluorescent or ultraviolet (UV) -absorbing products. The electrolyzed eluent then passes into a suitable detector. An example of the use of this technique is in the detection of thiamine which was found to form a highly fluorescent product, thiochrome, by electrochemical oxidation in the presence of sodium hydroxide. In the present investigation, we used such a flow injection method to determine thiamine content specifically in some pharmaceuticals.