Synchronous Fluorescence as a Rapid Method for the Simultaneous Determination of Folic Acid and Riboflavin in Nutritional Beverages

A rapid synchronous spectrofluorimetric method was first developed for the simultaneous determination of folic acid and riboflavin in nutrimental beverages. Folic acid could be detected by using H2O2 plus Cu(II) as oxidation system to produce pterine-6-carboxylic acid, which had strong fluorescence in aqueous solution, and riboflavin itself was obviously fluorescent. Various operational parameters were thoroughly discussed in terms of their effects on the fluorescence signals, including instrumental parameters, concentration of the oxidation system, and pH. Under optimum conditions, the calibration curves were linear in the ranges of 100-250 mu g/L for folic acid and 1-250 mu g/L for riboflavin, and the detection limits were 2.0 and 0.014 mu g/L, respectively. In addition, this method was applied to the determination of folic acid and riboflavin in nutrimental beverages with satisfactory results.