Development of a Ratiometric Fluorescence Sensor for Ascorbic Acid Based on Oxidase-mimicking Activity of CoOOH Nanoflake

This work aimed at developing a ratiometric fluorescence sensor for sensitive and accurate detection of ascorbic acid (AA) based on oxidase-mimicking activity of CoOOH nanoflake. CoOOH nanoflake with oxidase-like activity was prepared by using CoCl2 as precursor, NaClO as oxidant through a sonication method. The as-synthesized CoOOH nanoflake was characterized by transmission electron microscopy (TEM), UV–vis absorption, X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectra. Control experiments were used to demonstrate the feasibility for constructing the radiometric fluorescent sensor using the as-synthesized CoOOH nanoflake. Single-factor experiments were conducted to optimized the optimal concentration of CoOOH nanoflake and incubation time for AA detection. The results showed that the as-synthesized CoOOH nanoflakes exhibited typical hexagonal plate shape, and other characterization results also were consistent with those in previous works. The optimal concentration of CoOOH nanoflake wa