Abstract
Vitamin B1 showed three kinds of polarographic waves in alkaline media: (1) the unstable cathodic wave at negative potential as nearly -2.0 V. vs. N. C. E., (2) the catalytic wave of BRDICKA in usual cobalt buffer, and (3) the anodic wave with the half wave potintial of -0.439V. vs. N. C. E. (pH 11.0). These waves were eliminated by the reaction with monoiodoacetic acid. By the air oxidation, the anodic wave changed to two separate waves, one anodic and one cathodic, and also catalytic wave was eliminated. From these observations we pointed out that vitamin B2 converts to its SH-form in the alkaline media of pH above 9.0. Consequently, the percentage of the formations of SH-form at different pH was graphically calculated from the heights of the anodic waves in buffered solutions. In cobalt buffer, the catalytic wave was observed even with acidic medium as pH 4.0 and its shape was perfectly identical with that apearing in alkaline media. But a difference was found that the heights of maxima decreased gradually until almost zeor in 150 minutes at pH 10.6 and 9.6, while a little decreasing was observed in the first 30 minutes but its height was kept constant after then at pH 3.0 and 8.5.
