Kinetic Determination of Ultratrace Amounts of Ascorbic Acid with Spectrofluorimetric Detection

A simple, fast and highly sensitive fluorimetric method is reported for the determination of ultratrace amount of ascorbic acid. The method is based on the activating effect of ascorbic acid on the oxidation of rhodamine 6G by potassium bromate in the presence of vanadium(V), which acts as a catalyst. The detection limit for ascorbic acid is 0.62ng/ml; the linear range of the determination is 1.6-28ng/ml The proposed method was used to determine ascorbic acid in pharmaceuticals, fruit juices and vegetables with satisfactory results.