Radiolysis of pyridoxine (vitamin B6) in aqueous solution under different conditions

Aqueous solutions of pyridoxine (1 mM) without or with additive of K-3[Fe(CN)(6)] (2.5 mM) were gamma-irradiated at different doses and dose rate of 2.16kGy/h in the absence of air, in the presence of air or by their saturation with NO. The radiolytic products were analyzed with HPLC, mass spectrometry and UV spectroscopy. 2,4,5-Trihydroxymethyl-3-pyridinol, pyridoxal, isopyridoxal and 6-hydroxypyridoxine were formed by radiolysis in tile absence of K-3[Fe(CN)(6)], and their concentrations were much higher in samples saturated with N2O. Pyridoxi-3,6-quirione was found by radiolysis under all tile above-mentioned conditions but only in the presence of K-3[Fe(CN)(6)]. Besides, the pyridoxal formation increased in the presence of this oxidizing agent. G values of pyridoxal formation and pyridoxine degradation were quantified. Some details of the radiolytic product formation were discussed. (c) 2007 Elsevier Ltd. All rights reserved.