1982 Volume 31 Issue 9 Pages 513-517
Measurement of sulfur was attempted to simplify the determination of thiamine hydrochloride. Thiamine hydrochloride did not react with bromine in an acidic solution, but after heating with a 10 % NaOH solution on boiling water bath followed by cooling in ice water, it could be titrated with a 0.02 N KBrO3-KBr solution in an HCl-acidic solution. The yellowish thiamine hydrochloride solution colored by heating with NaOH was decolored by this titration and then the decolored solution returened yellow again with surplus bromine. At the time, a potassium iodide solution and starch were added to the recolored solution, which was back titrated with a sodium thiosulfate solution. The defference of both titres corresponds to the content of thiamine hydrochloride in the original solution.One mole of thiamine hydrochloride was reacted with 4.3 equivalents of KBrO3-KBr that correspond to 4.3 equivalents of bromine atom.This reaction mechanism cannotbeelucidated, however, as 4.3 equivalents of bromine are quantitatively reacted with one mole of thiamine hydrochloride, this method may be used for determining thiamine hydrochloride.The most suitable recipe is that(1050)mg of sample (thiamine HCl)are taken and the solution is heated with (1020)% NaOH for 15min.As this method is not influencedby D-glucose, thiamine hydrochloride in the commercial injections that usually contain large amounts of glucose may be determined with ease by this method.Precission of this method was within ±0.5%.
