抄録
A new method for the determination of labeled thiamine or its derivatives, in stead of the widely applied wet oxidation method was deviced. The labeled thiamine or its derivatives in the materials was purified with permutit as usual and converted to thiochrome by the addition of BrCN and NaOH, then thiochrome was extracted with butanol. The butanol extract was dried up in a dish under infrared lamp and the counts of radioisotope was measured. The merits of this new method are as follows. 1) It does not require the troublesome oxidation with perchloric acid and nitric acid. 2) It is possible to assay in a shorter time than by the wet oxidation method. 3) The margin of the error is smaller compared with the wet oxidation method. 4) The sensitivity is much higher than that of the wet oxidation method. 5) This method is available not only for the determination of ^<35>S-labeled thiamine or its derivatives but also of ^<14>C-labeled compounds.
