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

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.