A sensitive colorimetric method for estimation of ascorbic acid.

The reaction of ascorbic acid with ammonium molybdate to give molybdenum blue was investigated and used for microestimation of the vitamin in the pure state, dosage forms and plasma. The proposed method couples sensitivity (as little as 2 microg/ml can be determined) and specificity since no interference was found in the presence of common reducing sugars, antioxidants and degradation products of the vitamin. Recovery varied from 98.9 to 102.3% +/- 0.2-0.5%.