Zinc Oxide Nanorod-Based Sensor for Precision Detection and Estimation of Residual Pesticides on Tea Leaves

This study presents the development of a zinc oxide (ZnO) nanorod-based sensor for the detection and quantification of residual pesticides commonly found in tea plantations, with a focus on quinalphos and thiamethoxam. Exploiting the unique electrical characteristics of ZnO nanorods, the sensor exhibits high sensitivity and selectivity in monitoring trace levels of pesticide residues. The detection mechanism relies on measurable changes in electrical resistance when the ZnO nanorod-coated electrodes interact with varying concentrations of the target pesticides. A performance evaluation was carried out using water samples spiked with different pesticide concentrations. The sensor displayed distinct response profiles for each compound: a linear resistance–concentration relationship for quinalphos and a non-linear, saturating trend for thiamethoxam, reflecting their differential interactions with the ZnO surface. Statistical analysis confirmed the sensor’s reliability, reproducibility, and consistency across repeated measurements. The rapid response time and ease of fabrication underscore its potential for real-time, on-site pesticide monitoring. This method offers a promising alternative to traditional analytical techniques, enhancing food safety assurance and supporting sustainable agricultural practices through effective environmental surveillance.