Electrochemical Determination of Paraquat Using Ordered Mesoporous Carbon (CMK-3) Modified Glassy Carbon Electrode

Abstract

Herein, one of the ordered mesoporous carbons, CMK-3, was synthesized using nanocasting method and characterized using various physico-chemical analytical tools like X-ray diffraction, Raman, Brunnauer-Emmett-Teller, high-resolution scanning electron microscopy, and high-resolution transmission electron microscopy. From the physicochemical analysis, we determined that CMK-3 was successfully formed. It was then employed as an electrocatalyst for the determination of paraquat (PQ). Due to modification of the electrode the active surface area of the electrode increases, thereby enhancing the sensitivity for determination of PQ in phosphate buffer solution at pH 9.2 when compared to bare GCE. From the anodic stripping squarewave voltammetry, the sensitivity and limit of detection against the herbicide were evaluated as 9.512 µA/µM and 64 nM, respectively. The interfering ability of the other foreign molecules like metal ions, environmental samples, biomolecules, and pesticides were analysed using CMK-3/GCE. The results revealed that the electrode is able to sense paraquat, with the retention in sensitivity ranges between 91% and102%. Hence, it is believed that the electrode was selective in producing signal against PQ. The real time applicability of the electrode was examined using vegetable and fruit extracts. The analysis produces the recovery values between 102-105%.