Sensitive colorimetric sensing of glutathione and H2O2 based on enhanced peroxidase mimetic activity of MXene@Fe3O4.

Abstract

Theperoxidase-like activity of MXene@Fe3O4 nanocomposites and the relevant colorimetric application have been investigatedfor the first time. According to a kinetic study, MXene@Fe3O4 nanocomposites displayed higher peroxidase activity than their individual components, and the catalytic process followed a ping-pong mechanism. The improved peroxidase-like activity of the MXene@Fe3O4 nanocomposites was obtained due to the synergetic impact of the Fe3O4 and MXene phases, the huge ion-accessible interface, and quick electron transfer channels in the nanocomposites. In the presence of hydrogen peroxide (H2O2), the MXene@Fe3O4 nanocomposites can catalyze the reaction of the colorless substrate 3, 3, 5, 5-tetramethylbenzidine (TMB) into oxidized TMB which revealed a blue color at 652nm. After the introduction of glutathione (GSH), the blue color was gradually fading owing to the hydroxyl radical scavenging effect of glutathione. A colorimetric detection platform based on the peroxidase-like activity of the MXene@Fe3O4 nanocomposites was developed for H2O2 and GSH with a detection limit of 0.4μM and 0.5μM, respectively. Thecalibration plot for glutathione detection is calculated by absorbance difference at 652nm, which ranged from 0.5 to 10μM with a detection limit of 0.2μM. The recoveries of GSH with different concentrations ranged from 93.76 to 108.50% and the relative standard deviation from 0.30 to 5.96%. This work significantly extends the application of MXene@Fe3O4 nanocomposites in the construction of colorimetric sensors and reveals a satisfactory result in real sample analysis.