PH OPTIMUM OF THE REDUCTION OF DEHYDROASCORBIC ACID BY DITHIOERYTRITOL

Ascorbic acid is a water soluble antioxidant, that is itself oxidized to dehydroascorbic acid. In order to detect dehydroascorbic acid by am perometri it has to be reduced to ascorbic acid beforehand. This reduc tion was performed with dithioerytritol at pH = 6.0 for 10 min, which is a choice between optimal reaction rate and stability of ascorbic ac id. The limit of detection of ascorbic acid is 1.1 pmol making the ass ay useful for determination of ascorbic and dehydroascorbic acid in sm all tissue biopsies. Results of this method and a colorimetric method were comparable.