Colorimetric Nanozyme Sensor Array Based on Metal Nanoparticle-Decorated CNTs for Quantification of Pesticides in Real Water and Soil Samples

Pesticides have become a concern to the environment and human health, since they are frequently employed to control pests and regulate plant growth. Although array-based pattern recognition has been demonstrated to be a successful method for identifying a variety of analytes, developing sensing components that possess a desirable surface diversity remains a difficult task. Herein, we fabricated a metal nanoparticle-decorated CNT (MDC) nanozyme in the presence of a cationic receptor to produce diverse noncovalent interactions when various pesticides were adsorbed on the MDCs, which resulted in the enhancement of their peroxidase-mimicking activities with different degrees, and utilized it as a colorimetric sensor array for pesticide identification. The designed MDC sensor array could successfully distinguish eight pesticides that exhibited different fingerprint-like sequences at a concentration of 10 μM or successfully segregated CBZ, DTM, and ISP pesticides having a linear range varying from 1 to 8 μM and quantified as low as 10.8, 28.8, and 16.8 nM with R2 values of 0.983, 0.949, and 0.977, respectively. Very interestingly, two pesticides having similar structures (CBZ and ISP) have been precisely discriminated by a sensor array without any overlapping. Additionally, the effective segregation of pesticides in spiked soil and water samples without cross-classification demonstrated the practicability of the MDC sensor array.