Synthesis of cobalt-modified MSN as a model enzyme: Evaluation of the peroxidatic performance

Abstract

Abstract The cobalt incorporated mesoporous silica nanomaterials (Co-MSN) with different ratios of Si/Co in the framework were synthesized. The as-obtained products were characterized by X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FT-IR), X-ray fluorescence (XRF), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), N2 adsorption/desorption (BET) and UV–Vis spectroscopic techniques. The effect of the various content of Co incorporated into the framework on the catalytic activity was studied. The Co-MSN samples exhibited an excellent catalytic activity toward the reduction of hydrogen peroxide (H2O2) and the oxidation of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) as a chromogenic substrate and followed Michaelis−Menten kinetics. It means that they have intrinsic peroxidase-like activity. The results showed that the Co-MSN catalyst with Si/Co = 75 (as the optimum ratio), has the higher affinity to ABTS and H2O2 and higher catalytic efficiency. These features made this nanocatalyst suitable to apply for the determination of H2O2 and glucose. The linear range for detecting H2O2 was from 22.5 μM to 0.2 mM with a detection limit of 6.7 μM. Coupled with glucose oxidase, the Co-MSN(75) was successfully used for the determination of glucose with the linear range of 11.6 μM−0.1 mM and a detection limit of 3.5 μM.