Gamma Radiation-Induced Effects on Riboflavin Epr Investigation and Spectroscopic Analyses

Electron paramagnetic resonance (EPR) spectroscopy was used to investigate the gamma radiation induced free radicals in the riboflavin (RF, vitamin B2) and the behavior of the radicals upon radiation sterilization of RF. The physicochemical properties of RF subjected to γ-rays were also investigated by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and ultraviolet-visible spectrophotometry (UV-Vis). The un-irradiated RF exhibits a very weak EPR signal (g = 2.00950) and upon γ-ray exposure the signal increases proportionally with increasing absorbed dose. The EPR signal of irradiated RF decays significantly during the first week of storage then tends to decrease slowly until the end of 100 days of storage period. It was reported also that no significant changes in the FTIR spectra, XRD pattern and UV-Vis spectra of RF dry samples were observed upon γ-ray exposure up to an absorbed dose of 50 kGy.