Abstract:

The detection of folic acid by a fluorescent energy transfer method has been developed. In the folic acid-KMnO4-Eu3+-H2O2 system with the presence of HAc-NaAc buffer solution（pH=4.7, 0.2 mol/L), the folic acid can be oxidized by KMnO4 with the presence of H2O2 and converted into the purine of butterfly-6-carboxyl acid, which can coordinate with Eu3+ forming a complex. The experimental conditions including the concentration of buffer solution and pH value, choice of oxidant, the temperature and heating time, the concentration of Eu3+, etc., were optimized. This system can emit the characteristic fluorescence of Eu3+ through an intra-molecule energy transfer process. The fluorescent intensity is in proportional to the concentration of folic acid in the range of 4×10-8~4×10-5 mol/L with correlation coefficient of 0.9902. The detection limit is found to be 1.2×10-8 mol/L. The developed method has been successfully applied to the determination of folic acid in the actual samples.

Key words: folic acid, Eu, fluorescence