抄録
A fluorometric determination procedure of O-benzoylthiamine disulfide (BTDS) was established based on the results of fundamental investigations on the optimum condition for reduction of BTDS with sodium thiosulfate or cysteine. BTDS (1-100μg) was reduced quautitatively with 40mg of sodium thiosulfate at pH 4.0-5.0,60℃ for 20 minutes and with 5mg of cysteine hydrochloride at pH 8.4-8.8,37℃ for 60 minutes. Sodium thiosulfate reduced BTDS to O-benzoylthiamine (OBT) and a mixture of OBT and thiamine was produced with cysteine. The products were determined by the thiochrome method, since OBT was also converted to thiochrome with cyanogen bromide and alkali. When BTDS, thamine and esterified thiamine were contained together in blood, the total thiamine was satisfactorily determined as usual by the thiochrome method after hemolysis and diastase hydrolysis.
