Ionic liquid coated zerovalent manganese nanoparticles with stabilized and enhanced peroxidase-like catalytic activity for colorimetric detection of hydrogen peroxide

Nanomaterials based colorimetric detection is an area of vital importance in the field of sensing applications. The nanoparticles are the main component of colorimetric sensor in replacing the natural enzyme based sensor. In this context, zero valent nanoparticles have revolutionized the field of optical sensing especially due to easily shift of electron, facile and low cost of preparation, and ease of surface modification. In this work, zero valent manganese nanoparticles (ZV-Mn NPs) are prepared through a simple and very quick method and modulated with new type of ionic liquid (IL). As-prepared materials were characterized through FE-SEM, HR-TEM, BET, FTIR, and XRD. Subsequently, the peroxidase like catalytic activity of pure and modified ZV-Mn NPs to catalyze oxidation of N,N′,N,N′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H₂O₂) investigated. Moreover, the absorbance peak is observed at wavelength 652 nm. The enhanced catalytic activity of ZV-Mn NPs was attributed to the fast transfer of electron mechanism in between substrate and H₂O₂. The coating of IL on ZV-Mn NPs permitted a low limit of detection 0.2 μM with a linear range of 10–280 μM. This work can find wide spread interest in the colorimetric sensing applications. In order to verify the successful demonstration of H₂O₂ sensor, we have applied it in the dairy milk products with satisfactory results. (paper)