Antioxidants Recognition Colorimetric Sensor Array Based on Multicolor System

A colorimetric sensor array with three identification signals has been developed to visually recognize five antioxidants based on CuFe Prussian blue analogs nanocubes (CuFe PBA NCs) and 3,3′,5,5′-tetramethylbenzidine (TMB). The CuFe PBA NCs can oxidize TMB to produce three ultraviolet–visible (UV–Vis) absorption peaks at different wavelengths (370, 450, and 650 nm). Depending on the different reduction capacity of dopamine, cysteine, ascorbic acid, glutathione, and melatonin, the redox process can be inhibited to varying degrees, resulting in different changes in the signal generation of three identification elements. And in the presence of different antioxidants, the color of the solution also changes in different degrees. Five antioxidants (20 μM) can be identified by this colorimetric sensor array, and the identification accuracy was 100% for 40 unknown antioxidants. In addition, these antioxidants can also be quantified based on the regression equation between the concentration of the antioxidants and the absorbance change. The correlation coefficient is greater than 0.990, and the detection limit is less than 3.5 μM.