Abstract
A precise and sensitive method for the fractional determination of thiamine and 2-(1-hydroxyethyl)thiamine (HET) in biological materials was described. Thiamine compounds in tissues were extracted by homogenizing and heating in an acidic medium, and dephosphorylated by phosphatase after deproteinization by metaphosphoric acid. The extract was partially purified by adsorption on permutit and elution with hot KCl-HCl solution. WET in the eluate was determined by a thiochrome method using ferricyanide as the oxidizing agent after destroying thiamine by an alkaline incubation in the presence of a small amount of mercuric ion. Thiamine, on the other hand, was determined without interference of HET by a thiochrome method using mercuric chloride as the oxidizing agent. The reliability of this method was not appreciably affected by the molar ratio of thiamine and HET, and a small amount of HET could be determined precisely in the presence of excess thiamine.
