?-CYCLODEXTRIN ENHANCED FLUORIMETRY FOR A DETERMINATION OF ASCORBIC ACID

A simple, sensitive and selected fluorimetry for determination of ascorbic acid (AA) is described. The method is based on the reaction of ascorbic acid in alkaline medium with 2,3diaminonaphthalene without oxidant. The addition of ?cyclodextrin (?-CD) greatly enhance A the fluorescence of the system. Under optimum conditions, a linear relationship was obtained between the fluorescence intensity and the concentration of ascorbic acid in the range of 0.05-600 µg/ml, the detection limit is 8 ng/ml. In AA-DAN-?-CD system, the inclusion complex is formed. Its inclusion constant is 1.1 × 106L2/mol2.