Synthesis, characterization and fluorescent properties of cerium(III) glutathione complex.

The cerium (III) glutathione complex was synthesized by the redox reaction of cerium (IV) with glutathione reduced (GSH) in aqueous solution. The Job-plots indicate an ML (L = GSSG) stoichiometry of the complex. The fluorescent properties of the compound were investigated. The as-prepared complex showed the characteristic maximum emission spectra of Ce(III) at 350 nm (λ(ex) = 255 nm). The fluorescence results show that the Ce(IV) ions are first reduced to Ce(III), and then form Ce(III) complex after reacting with GSH. The complex was characterized by element analysis and FT-IR spectra; the stability of the complex was analyzed by cyclic voltammeters and DSC-TG as well. Finally, Ce(IV) was successfully employed to determine the concentrations of GSH in the presence of GSSG, in which the fluorescence intensities are proportional to the concentrations of GSH in the range of 1-100 nM with the detection limit of 0.05 nM of GSH, without interference from the presence of GSSG.