Poly(o-phenylenediamine)-Multiwalled Carbon Nanotube Nanocomposite Based Electrochemical Sensing Platform for Paraquat Detection

Poly(o-phenylenediamine)-Multiwalled Carbon Nanotube nanocomposite was prepared by the electropolymerization of o-phenylenediamine (PoPD) onto the functionalized multiwalled carbon nanotube nanocomposite (MWCNT) which acts as the good sensing materials for the electrochemical sensing of paraquat. Atomic force microscopy (AFM) image confirms somewhat large agglomerated structures suggesting the deposition of PoPD onto the MWCNT. The electrochemical reduction of paraquat at four electrodes viz. glassy carbon electrode (GCE), MWCNT/GCE, PoPD/GCE and PoPD- MWCNT/GCE are studied. The cyclic voltammograms has been studied for the electrochemical reduction of paraquat at four different electrodes such as glassy carbon electrode (GCE), MWCNT/GCE, PoPD/GCE and PoPD-MWCNT/GCE. Poly (o-phenylenediamine)-Multiwalled Carbon Nanotube nanocomposite shows highest cathodic current compared to other modified eletrodes. Different experimental parameters such as influence of scan rate and pH have been optimized for the sensor studies. The sensor calibration plot for paraquat has been constructed using square wave voltammetry (SWV) sensor in the linear range from 8.8 x 10-7 M to 2.5 x 10-8 M. The developed sensor resulted in a detection limit and current sensitivity values of 1.4 x10-9 M and 80.38 pA pM-1 respectively. Real sample analysis for cabbage samples and interference studies in the presence of selected metal ions and surfactants have been carried out.