Ionic liquid assisted synthesis of h-MoO3 hollow microrods and their application for electrochemical sensing of Imidacloprid pesticide in vegetables

Abstract

Herein, we demonstrate the ionic liquid (1-butyl-3-methylimidazolium bromide [BMIM]+ [Br]−) assisted solvo-hydrothermal synthesis of novel hexagonal MoO3 hollow microrods (h-MoO3 HRs). The h-MoO3 HRs were preferentially obtained through the formation of electric double layer and strong electrostatic interactions of ionic liquids with colloidal particles, including the electrons and ions. As-synthesized h-MoO3 HRs were further anchored on glassy carbon electrode (h-MoO3 HRs/GCE) and directly employed as a working electrode towards the electrochemical sensing of Imidacloprid (IMD) pesticide. The electrochemical response of IMD at h-MoO3 HRs/GCE was verified by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The h-MoO3 HRs/GCE electrode exhibited two distinct quasireversible redox couple towards IMD. From the CV and DPV, the sensitivity was calculated to be 2.02 × 10−1 A L mol−1 cm−2 and 1.39 × 10−1 A L mol−1 cm−2, respectively. Under optimal conditions, h-MoO3 HRs/GCE sense IMD with wide linear range of CV from 38.7 to 114 μM and from DPV 38.7 to 132 μM. The estimated detection limits from CV and DPV was calculated as 8.3 and 5.9 μM, respectively. In view of practical application, the proposed electrochemical sensor h-MoO3 HRs/GCE is successfully applied for the detection of IMD at low levels in vegetable samples. © 2020 Elsevier B.V.