Quantitative Fluorometric Microdetermination of Alloxan Monohydrate as Riboflavin

Reinvestigation of Alloxantin and Dialuric Acid

“…Nitrogen was now passed in through the side arm, the condenser was removed, 25 g. of dry, crude alloxantin dihydrate was added, the stopcock was closed and the condenser replaced, and (with nitrogen admitted through the condenser) the suspension was boiled under reflux until the crystals had just dissolved. The heat source was removed, the condenser was quicldy replaced by a rubber stopper through which passed nitrogen inlet and outlet tubes, and the flask was tilted through 90°so that the stopcock was underneath.…”

“…The colorless crystals were filtered off under nitrogen and dried in the vacuum-desiccator; yield (dry), 22.5 g. [cf. (25)].…”

Reduction of Alloxan in Aqueous Solution. II. Effect of Certain Organic Reductants at pH 1.6

“…This is a much poorer sensitivity than is achieved b y the fluorometric procedure we previously reported (13). However, even in the presence of, say, cysteine, this peak results on reduction with excess hydrogen sulfide.…”

“…According to the literature , alloxan in aqueous solution is reduced by excess cysteine (5-lo), glutathione (9-ll), or L-ascorbic acid (7, 12,13).…”

Reduction of alloxan in aqueous solution. I. By hydrogen sulfide

“…It was colorless, and readily and completely soluble in five volumes of cold water. It assayed 99-100% alloxan monohydrate by Tipson and Cretcher's method (32). From our experiment reported above, it is seen that the organic product is soluble to the extent of ca.…”