Spectrofluorimetric determination of 5-fluorouracil by fluorescence quenching of 9-anthracenecarboxylic acid.

Photo-induced intermolecular electron transfer (PET) interaction between excited singlet (S(1)) state of 9-anthracene carboxylic acid (9-ANCA) and DNA bases of pyrimidines as uracil and 5-fluorouracil (5-FU) has been studied in water and ethanol solutions using steady-state fluorescence spectroscopy. The intensity of all emission bands of 9-ANCA was quenched in presence of uracil and 5-FU by electron transfer reaction without formation of an exciplex. It was found that uracil and 5-fluorouracil acts as effective electron donors and simultaneously quench the fluorescence of electron-accepting sensitizer 9-ANCA.