Colorimetric glutathione assay based on the peroxidase-like activity of a nanocomposite consisting of platinum nanoparticles and graphene oxide

This work describes a colorimetric glutathione (GSH) assay that is taking advantage of (a) the peroxidaselike activity of a nanocomposite prepared from platinum nanoparticles and graphene oxide (PtNP/GO), (b) the decolorizing reaction of GSH with oxidized 3,3', 5,5'-tetramethylbenzidine (TMB), and (c) the GSH-induced scavenging of hydroxy radicals produced from H2O2. The assay has a detection limit as low as 4 nM of GSH. It is flexible because it involves a single step reaction. The method was successfully applied to the determination of GSH in hemolyzed human blood. The concentrations determined by this method in GSH-spiked blood samples ranged from 95.0 to 112.5%, with relative standard deviations between 0.5 and 4.2%.