Colorimetric detection of glutathione in human blood serum based on the reduction of oxidized TMB

In this paper, a novel and simple colorimetric method for the determination of glutathione (GSH) was developed. The BSA–MnO2 NPs possess oxidase-like activity that can catalyze the oxidization of 3,3′,5,5′-tetramethylbenzidine (TMB), and the existence of GSH can cause reduction of oxidized TMB along with a visual color variation. A good linear relationship can be obtained from 0.26 to 26 μM with a limit of detection of 0.1 μM. Furthermore, the good recoveries for serum samples indicated that the present colorimetric methodology was feasible, simple and sensitive, with a promising application in routine analysis of biosamples.