Photophysical and photochemical processes of riboflavin (vitamin B2) by means of the transient absorption spectra in aqueous solution

Using time-resolved techniques of 337 and 248 nm laser flash photolysis, the photophysical and photochemical processes of riboflavin (RF, vitamin B-2) were studied in detail in aqueous solution. The excited triplet state of riboflavin ((RF)-R-3*) was produced with 337 nm laser, while under 248 nm irradiation, both (RF)-R-3* and hydrated electron (e(aq)(-)) formed from photoionization could be detected. Photobiological implications have been inferred on the basis of reactivity of 3RF* including energy transfer, electron transfer and hydrogen abstraction. The RF.+ was generated by oxidation of SO4.- radical with the aim of confirming the results of photolysis.