Fabrication of a Highly Sensitive and Selective Electrochemical Imidacloprid Sensor Using a Glassy Carbon Electrode Modified With MWCNTs/SBA-15@Si-CDs Nanocomposite
Nafiseh Kazemifard, Ali A. Ensafi, Marziyeh Poshteh Shirani
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 μ\textmol L <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> with a detection limit of 0.020 μ\textmol L <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> IMD. The evaluation of the effects of potentially interfering species showed that the method has high selectivity towardIMD's determination.Themethod's applicabilitywas also evaluated insome cropsamples, and its results were comparedwith those obtained by HPLC. No significant differencewas observed between the proposed and theHPLC 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.