Abstract
Polarographic reduction potentials of 2, 6-dichlorophenolindophenol were determined by the half-wave method and the results agreed with the normal redox potentials determined in the CLARK'S laboratory by the usual potentiometric method.
The reduced form of 2, 6-dichlorophenolindophenol was obtained by the electrolytic reduction using platinum cathode, and it was confirmed that its oxidation potential coincided with its redp-ction potential of the oxidized form. I The rate of oxidation of the reduced form by aeration is not constant with the pH of the med-ium; the rate is very slow at pH<6 and is very large at pH>7.
It could be concluded that 2, 6-dichlorophenolindophenol is reversible within the pH range of 4, 1<pH>11.7 and irreversible at pH<3.5 or pH>12.2.
2, 6-dichlorophenolindophenol has the tendency to decorppose especially in acidic or alkaline medium; for instance at pH 3.2, 82% is decomposed on 5 hours' standing.
That 2, 6-dichlorophenolindophenol is reduced by Na
2SO
3, Na
2S
2O
4, glutathione, and vitamin C has been proved polarographically.
