Fabrication of a highly sensitive and selective modified electrode for imidacloprid determination based on designed nanocomposite graphene quantum dots/ionic liquid/multiwall carbon nanotubes/polyaniline

Abstract

In this paper, a simple, selective and sensitive electrochemical method was developed for the determination of imidacloprid. To fabricate the modified electrode, at first, a glassy carbon electrode (GCE) was modified with a nanocomposite consist of graphene quantum dots/ionic liquid/multiwall carbon nanotubes (GQDs/IL/MWCNTs). Then, polyaniline (PANI) film was formed on the surface of GQDs/IL/MWCNTs by electropolymerization via cyclic voltammetry at a surface of the modified GCE. Field emission scanning electron microscopy and transmission electron microscopy were used for elucidation the GQDs/IL/MWCNTs/PANI surface characterization. For investigation the electrochemical behavior of imidacloprid at the GCE/GQDs/IL/MWCNTs/PANI, cyclic voltammetry and differential pulse voltammetry techniques were utilized. Also, the effective variables on the modified electrode such as pH, electropolymerization cycles, accumulation potential and accumulation time were studied. The proposed modified electrode showed a linear range from 0.03 to 12.0 μmol L−1 imidacloprid with a detection limit of 9 nmol L−1. This modified electrode exhibited good repeatability and excellent selectivity. The proposed modified electrode was employed for imidacloprid determination in vegetable samples.