Ascorbic acid, riboflavin and pteroyl glutamic acid in multi-vitamin preparations are determined polarographically at the same time in phosphate buffer (pH 6.8) by means of the anodic wave E1/2 -0.05,the reduction wave E1/2 -0.47 and the reduction wave E1/2 -1.2 V vs NCE respectively. The reduction wave E1/2 -0.41 V in 0.1 N HCI solution is also used for partial determination of pteroyl glutamic acid.
