Preparation of NiMn2O4/C necklace-like microspheres as oxidase mimetic for colorimetric determination of ascorbic acid

The NiMn2O4/C necklace-like microspheres (NLM) were successfully prepared by hydrothermal method and oil bath. This unique necklace-like structure makes them exhibit the enhanced intrinsic oxidase-like activity, as the special interface can help capture electrons from 3,3′,5,5′-tetramethylbenzidine. The fabricated NiMn2O4/C NLM were successfully used as the high-performance oxidase mimetic to catalyze the oxidation of TMB directly for the color reaction. A simple colorimetric method for detection of ascorbic acid by fading was developed, and the high sensitivity with the low detection limit (0.047 μM) was achieved. It is a facile route to fabricate the NiMn2O4/C NLM as the high-performance oxidase mimetic for colorimetric biosensing. [Display omitted] •The NiMn2O4/C necklace-like microspheres are successfully prepared by hydrothermal method and oil bath.•They can be used as the high-performance oxidase mimetic to catalyze the oxidation of TMB directly.•The enhanced intrinsic oxidase-like activity results from the special interface that can help capture electrons from TMB.•A simple colorimetric method for detection of ascorbic acid with the lowest detection limit (0.047 μM) was achieved.