A new poly carboxylic catex polymer-gold nanoparticles modified electrode for determination of paraquat by voltammetry method

Abstract

A new catex polymeric-gold nanoparticle composite modified electrode for the determination of paraquat (PQ) in various samples is introduced. Fabrication of the electrode is based on casting a poly carboxylic polymer on a glassy carbon electrode, which was prepared separately in an electrochemical system; after which electrodeposition of the gold particles on the surface of electrode took place. The morphology of the electrode surface was investigated by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectrometry (EDS) and mapping. Chemical structure of prepared composite was studied by differential scanning calorimetry (DSC), Fourier-transform infrared spectrometry (FTIR), and H NMR spectrometry. The obtained results show that the prepared polymer is a weak catex with carboxylate groups. The presence of the gold particles in the composite enhanced the sensitivity of the electrode for the determination of paraqaut. The application of this electrode for determination of paraquat is based on the redox property of paraquat. The fabricated electrode shows a wide range of linearity (1.9 × 10−8−7.8 × 10-7 mol L-1) and LOQ (7.78 × 10-10). The mean, standard deviation and RSD for five repetitive determinations of paraquat (3.20 × 10-7 mol L-1) are 3.15 × 10-7 mol L-1, ±1.40 × 10−8 mol L-1 and 4.28 % respectively. This electrode was successfully applied for determination of paraquat in natural waters and soils. The obtained results were compared with the results of standard methods. The characteristic parameters of the offered method were compared with other electrochemical methods.