Distinction of antioxidants using a three-channel colorimetric sensor array constructed with bimetallic FeCo nanozyme

The content of antioxidants in food is related to the dietary safety of consumers. In this context, two dimensional (2D) iron/cobalt metal nanosheets (Fe/Co NSs) are synthesized through the synergistic self-assembly reaction of Fe3+/Co2+ with terephthalic acid. This Fe/Co NSs exhibit excellent peroxidase-like activities. Based on nanozyme property of Fe/Co NSs, three-channel sensor array based on Fe/Co NSs nanozyme is constructed using 3,3',5,5'-tetramethylbenzidine (TMB) as colorimetric substrate and three wavelengths (370, 456, and 654 nm) as array’s channels, enabling distinct absorbance response signals for the identification of five antioxidants with a 100% accuracy. The sensor array is able to accurately detect the five antioxidants in the range of 100 nM-100 μM, achieving accurate quantitative analysis. The sensor array also has excellent anti-interference ability to other interferents even at high concentration. These abilities endow the sensor array with great potentials for discrimination of blind and actual antioxidant samples.