Abstract: The development of an indirect fluorimetric method for the determination of folic acid using Fenton reagent as oxidant is presented in this paper on the basis of the fact that after heating in a water bath at 80 ℃ for 8 min, hydroxyl radicals generated from Fenton reagent oxidize folic acid into pterin-6-carboxylic acid, whose fluorescence intensity is much higher than that of folic acid. The method displayed a linear relationship between fluorescence intensity and folic acid concentration over a range from 0.02 to 1.0 mg/L. The limit of detection was 2.69μg/L. The average recoveries for folic acid in pear, apple and cabbage separately spiked at three levels were between 91.0% and 96.1%. This method has been applied to determine the three fruits or vegetables, with satisfactory results. 

Key words: fluorimetry, folic acid, Fenton reagent