Novel synthesis of NiS/MMT/GO nanocomposites with enhanced peroxidase-like activity for sensitive colorimetric detection of glutathione in solution

In the present study, a facile method was proposed to prepare nickel sulfide (NiS) nanoparticles well-dispersed on the surface of montmorillonite/graphene oxide (MMT/GO). The NiS/MMT/GO nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), fluorescence spectrophotometry, etc. Significantly, the novel NiS/MMT/GO nanocomposites exhibited high peroxidase-like activity toward the typical chromogenic substrate, 3,3′,5,5′-tetramethylbenzidine (TMB). However, glutathione (GSH) could inhibit the peroxidase-like activity of NiS/MMT/GO along with a visible color variation. Based on the color change of the system of nanocomposites-H2O2-TMB, a novel colorimetric sensor was designed and conveniently used to quantitatively detect H2O2 as well as GSH. The limit of detection (LOD) of H2O2 and GSH is 9.73 and 0.5043 μM, respectively. The proposed H2O2 sensor has potential application in the field of biosensing, food, and environment.