Nickel ferrite nanoparticles on a carbonaceous matrix and their colorimetric assay for ascorbic acid detection

In this study, nickel ferrite nanoparticles highly dispersed in a carbonaceous matrix (C/NiFe 2 O 4 ) demonstrated a high catalytic activity oxidizing 3,3′,5,5′-tetramethylbenzidine (TMB) without the use of hydrogen peroxide. The blue color of oxidized TMB decreases by the introduction of ascorbic acid (AA) in the reaction system, which allowed the development of a colorimetric analytical method for AA detection. To achieve the best analytical performance, the parameters such as pH, temperature, reaction time, TMB concentration, and amount of C/NiFe 2 O 4 , were optimized. Under optimal conditions, the variation in absorbance measured at 653 nm was found to be proportional in the concentration range of 1.0 to 25 μmol L −1 with a detection limit of 0.26 μmol L −1 . C/NiFe 2 O 4 was synthesized following a simple combustion method using egg white as a fuel and carbon source, and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and vibrating sample magnetometry. Graphic abstract