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

The NiMnO/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 NiMnO/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 NiMnO/C NLM as the high-performance oxidase mimetic for colorimetric biosensing.