Nafiseh Kazemifard, Ali A. Ensafi , and Marziyeh Poshteh Shirani

IEEE SENSORS JOURNAL, VOL. 21, NO. 8, APRIL 15, 2021, https://ieeexplore.ieee.org/abstract/document/9350262

Abstract—In this work, a sensitive and highly selective electrochemical sensor for the determination of imidacloprid (IMD) is presented. This sensor was fabricated with the modification of a glassy carbon electrode using multiwall carbon nanotubes (MWCNTs) and mesoporous silica (SBA-15) that was modified with silane functionalized carbon dots (Si-CDs). The electrochemical studies were performed by two methods, including cyclic voltammetry (CV) and differential pulse voltammetry (DPV). After investigating and optimizing all of the instrumental and experimental parameters, the figures of merit of the suggested quantitative method were evaluated. Under optimal conditions, a linear range was measured from 0.05 to 3.5 µmol L−1 with a detection limit of 0.020 µmol L −1 IMD. The evaluation of the effects of potentially interfering species showed that the method has high selectivitytoward IMD’s determination.The method’s applicabilitywas also evaluatedin some crop samples, and its results were compared with those obtained by HPLC. No significant difference was observed between the proposed and the HPLC methods. Although MWCNTs and SBA-15 have been used in electrochemical sensors to measure different analyses so far, the SBA-15 modified with Si-CDs has been used in this work for the first time that increased the surface area, and improved the sensitivity of the method. The proposed electrochemical method is sensitive, selective, inexpensive, and rapid for IMD trace concentrations.

Index Terms—Electrochemical sensor, mesoporous silica, Si functionalized carbon dots, multiwall carbon nanotubes, imidacloprid