A New Fluorimetric Method for the Determination of Ascorbic Acid with Fluorescein and Iodine

A simple and sensitive fluorimetric determination method has been investigated for the determination of ascorbic acid with flourescein as fluorescence reagent. This mothod is based on the inhibiting effect of ascorbic acid on the reaction between flourescein and iodine at pH 7.2. The calibration graph is linear over the range 50～300 ng/mL ascorbic acid. The detection limit is 21.5 ng/mL. The proposed method has been used to determine ascorbic acid in pharmaceuticals and soft drinks with satisfactory results.