Far UV photolysis of uracil and cytosine in phosphate solution.

The photolysis of nucleobases, nucleosides and nucleotides (NA) was enhanced by phosphate under irradiation of medium pressure mercury lamp (MPML). Uracil and Cytosine in phosphate solution were selected to study the mechanism of phosphate effect. Photoproducts were produced in the irradiated uracil and cytosine of phosphate solution which have been isolated by anion exchange resin. Ultraviolet irradiation (190-220nm) of uracil in 0.05 mol/dm3 phosphate buffered solution at pH 8-9 leads to the production of a novel compound C4H5N2O6P which has been identified by UV, 1H-NMR spectroscopy and LC/MS/MS. The formation mechanism of the photoproduct and the kinetics were studied.