抄録
On determining thiamine sulfuric acid ester, even when a purified sample of it was used, by cyanogen bromide method, an isobutanol layer has always shown a weak fluorescence of about one-tenth intensity compared to a water layer. The water layer was repeatedly shaken with isobutanol and 5〜7% of its fluorescence was found to be lost at each extraction while isobutanol got extracted the same proportion of fluorescence. Moreover both the isobutanol and water layers contained only thiochrome sulfuric acid ester which was detected by paper partition chromatography. The equal mixture of thiamine and its sulfuric acid ester was estimated by this method. The thiamine value found was 9-10% higher than the expected one, while the thiamine sulfuric acid ester value determined by the fluorescence of a water layer was nearly the same as that from the sulfuric acid ester alone.
