Construction of a Disposable Modified Pencil Graphite Electrode for Sensitive, Simple, Cost‐Effective, and First Voltammetric Determination of Hymexazole Fungicide

Abstract Hymexazole is a systemic fungicide in the oxazole family that is widely used to control a variety of diseases caused by fungi, such as A phanomyces cochlioides , Fusarium, and Pythium . In this study, a simple, selective, disposable, and sensitive electrochemical poly(aniline) pencil graphite electrode (PANI/PGE) sensor was developed for the first time to study the behavior of hymexazole and quantitatively analyze by cyclic voltammetry (CV) and square wave voltammetry (SWV) for the first time on PANI/PGE. The PANI/PGE exhibited more effective catalytic performance than PGE, and the sensitivity of hymexazole was increased by nearly 70%. The electroactive surface area and surface morphology of the sensor were elucidated, and the pH effect, scan rate effect, electron transfer kinetics, and sensitivity were investigated in the determination of hymexazole. In addition, the oxidation mechanism of hymexazole was proposed for the first time. The SWV exhibited satisfactory dynamic linearity for hymexazole within 5.08–49.5 µg/mL with a detection limit of 1.53 µg/mL. The selectivity of the proposed modified electrode and hence the method for the determination of hymexazole was investigated in the presence of various pesticides. Finally, electrochemical determination of hymexazole was successfully performed in real samples with high recovery and low relative error on the modified PANI/PGE.