From Mn-Triazine Crystalline Framework to MnOx@NC: Biomimetic Double-Enzyme Activity and Labeling of Ascorbic Acid as Well as Application in Pharmaceuticals

Abstract

Imbalance in the levels of ascorbic acid (AA) can pose a risk to human health. Therefore, it’s essential to establish an accurate method for the detection of AA. In this work, a novel N-doped carbon composite (MnO x@NC) with dual enzyme-like activities to detect AA was prepared by calcination of Mn-MOF containing H ₃TTPCA ligand. Interestingly, the •O ₂ ^- that leads to its oxidase-like activity was not formed by dissolved oxygen, but came from the synergistic effect of lattice oxygen generated by calcination and the transformation of Mn ^II/Mn ^III/Mn ^IV, and the presence of H ₂O ₂ provided much •OH, which caused its peroxidase-like activity. Meanwhile, the residual N element came from H ₃TTPCA ligand assisted the catalytic process. Accordingly, a dual-signal sensing platform and smartphone-assisted recognition for detection of AA was developed and a colorimetric sensor array was established to distinguish three antioxidants. This work also demonstrates considerable promise for the detection of AA in authentic pharmaceuticals.

Keywords

Peroxidase-like activity / Oxidase-like activity / N-doped carbon composite / Ascorbic acid / Colorimetric detection / Biosensors / Enzyme catalysis / Mixed-valent compounds

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