Determination of glucose by using MoS2 nanosheets as a peroxidase mimetic enzyme

MoS2 nanosheets (MoS2 NSs), which exhibited peroxidase-like activity, were prepared using the hydrothermal method. The microstructure and element speciation of the MoS2 NSs were characterized using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), respectively. The obtained MoS2 NSs could catalyze the H2O2-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to form blue oxidized TMB (ox TMB) with an absorption peak at 652 nm. The effects of MoS2 NS concentration, incubation time, temperature, and acidity on the color development of TMB were investigated. Under the optimal conditions (1.0 μg mL−1, 40 min, 40 °C, pH 4.0), the increase in absorbance, which was induced by MoS2 NS-catalyzed TMB oxidation, enabled the detection of H2O2 ranging from 2.5 μmol L−1 to 300 μmol L−1. As H2O2 is one of the products of glucose oxidase (Gox)-catalyzed glucose oxidation, a colorimetric method was further established for measuring the concentration of glucose. The absorbance response was linearly dependent on glucose concentration of 2.5–200 μmol L−1, with a detection limit of 2.1 μmol L−1. The proposed method was applied to the assay of glucose in urine samples with satisfactory results.