Visual Sensor Arrays for Distinction of Phenolic Acids Based on Two Single-Atom Nanozymes

Although great achievements have been made in the studyof artificialenzymes, the design of nanozymes with high catalytic activities ofnatural enzymes and the further establishment of sensitive biosensorsstill remain challenging. Here, two nanozymes, i.e., ZnCoFe three-atomnanozyme (TAzyme) and Sn single-atom nanozyme (SAzyme)/Ti3C2T (x) , are developed, whichshow peroxidase-like catalytic activities by catalyzing the reactionof hydrogen peroxide (H2O2), 4-aminoantipyrine(4-AAP), and phenolic acids to generate colorimetric reactions. Theinvolvement of different phenolic acids leads to the generation ofdifferent color products. These subtle color-variation profiles betweenthese phenolic acids prompt us to exploit an electronic tongue basedon the two nanozymes to distinguish phenolic acids. Data interpretationby the pattern recognition method, such as linear discriminant analysis(LDA), displays good clustering separation of six different phenolicacids at concentrations of 0.1 mu M to 1 mM, validating the effectivenessof the colorimetric nanozyme sensor array.