DETERMINATION OF BLOOD ASCORBIC ACID

Since vitamin C has definitely been identified with ascorbic acid the clinical importance of this substance has increased. However, the interpre-tation of blood ascorbic acid values has been un-certain, in part, because of the variations in val-ues encountered in routine analyses. Tillmans, Hirsch and Hirsch (1) first developed the method of determining the presence of reduced ascorbic acid in serum. To make it clinically practical, this original method has been modified by Farmer and Abt (2, 3). Their procedure was to use metaphosphoric acid as a deproteinizing agent which had been introduced for this purpose by Fujita and Iwatake (4) and to determine the reduced ascorbic acid in the filtrate with 2: