Fe3O4@Au-metal organic framework nanozyme with peroxidase-like activity and its application for colorimetric ascorbic acid detection.

Abstract

A free radical scavenging system based on Fe3O4@Au/MOF-ABTS˙+ has formed the basis of a novel method for the highly sensitive and specific spectrophotometric determination of ascorbic acid (AA). The Fe3O4@Au/MOF nanozyme with magnetic separation properties was effectively prepared and evaluated using an environmentally friendly technique. Nanomaterials have the advantages of superparamagnetism, biocompatibility, chemical stability, and enhanced synergistic peroxidase-like activity, which can be utilized in catalysis to oxidise the peroxidase substrate 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) into a green-colored product in the presence of H2O2. AA as an antioxidant has scavenging effects on ABTS radicals and can reduce green ABTS˙+ to uncolored ABTS2-, contributing to a substantial reduction in green color. Based on such a premise, a highly selective and sensitive chromogenic sensing method depending on the peroxidase-like activity of the nanocomposites was developed in order to achieve the efficient detection of AA in real samples. Under optimum conditions, the proposed technique had a detection range of 0.001-0.1 mmol L-1, a limit of detection of 0.098 μmol L-1, and a detection time of only 30 seconds. The newly proposed colorimetric analysis method devoid of enzymes has broad application potential in the areas of quality control and quality and safety detection.