Three-Channel Sensor Array Based on Switchable Nanozymatic Reactions of a Novel Trimetallic Nanozyme for Anti-Interference Identification of Tea Adulteration

Nanozymatic sensor arrays are widely used, and the rationality and anti-interference of their sensor channel composition has been a hotpot research. Here, we report a trimetallic nanozymatic array sensor for interference-free differentiation of tea polyphenols via exhibiting different substrate specificities. The selection of three metals, Cu, Mn and Zn, for the preparation of nanozyme was made on the basis of the favorable enzyme-like activity and extensive substrate responsiveness. At low pH, the oxidase-like activity of the nanozyme selectively catalyses the colour development of the substrate TMB. However, under neutral conditions, the nanozyme exhibits minimal catalytic activity towards TMB, but instead displays selective catalytic activity towards phenol and 4-AP colour development. Furthermore, the nanozyme demonstrated negligible oxidase-like activity at high pH, yet displayed considerable catalase-like activity. Innovatively, a three channel sensor array was developed based on switchable nanozymatic reactions of the trimetallic nanozyme for the anti-interference identification of tea polyphenols and tea adulteration. The relatively non-interfering nanozymatic reaction and the assistance of machine learning recognition algorithms enable the sensor array to discriminate 100% of tea polyphenol species between 2-100 μM without concentration interferences. The nanozymatic reactions were completed within a short period of five minutes at room temperature, which is suitable for rapid on-site detection.