Photoactivated oxidase mimetics derived from dicyandiamide and barbituric acid for colorimetric detection of glutathione.

In this work, photoactivated oxidase mimetics was prepared by copolymerizing dicyandiamide with barbituric acid (BA) and characterized by X-ray diffraction pattern, Fourier transformed infrared spectrum, X-ray photoelectron spectroscopy, transmission electron microscopy, photoluminescence spectrum, diffuse reflectance spectrum. Experimental results and density functional theory calculation indicated that the substitution of nitrogen atoms by carbon atoms in tri-s-triazine structure due to the copolymerization of BA enhanced visible light absorption and weakened the barrier of photocarrier transfer. In the presence of visible light and oxygen, 3, 3', 5, 5'-tetramethylbenzidine was oxidized under the catalysis of photoactivated oxidase mimetics to produce a green colored product, which could be reduced by glutathione (GSH). Therefore, a facile method based on the photoactivated oxidase mimetic has been developed for colorimetric detection of GSH. The linear range for GSH was ranged from 2.0 to 50.0 μmol L-1 (R2 = 0.998) with the detection limit of 1.4 μmol L-1. The proposed method was applied to detect the cellular GSH with satisfactory results.