A Novel Electrochemical Sensor Based on Modified Carbon Paste Electrode with ZnO Nanorods for the Voltammetric Determination of Indole-3-acetic Acid in Plant Seed Extracts

Detection of indole-3-acetic acid (IAA), as a phytohormone, is important for precision farming, plant phenotyping, and crop management. Herein, IAA was detected in bean and wheat plant seeds extractions using zinc oxide nanorods/carbon paste electrode (ZnO NRs/CPE). ZnO NRs/CPE showed excellent electrocatalytic activity, high sensitivity, and selectivity toward the oxidation of IAA. The linearity range was from 30.×10⁻⁸ to 5.0×10⁻⁶ M (r²=0.996, n=10), with a detection limit of 1.7×10⁻⁸ M. Moreover, ZnO NRs/CPE exhibited high reproducibility, with a standard deviation of 1.0 % for six successive measurements of IAA.