Electrochemistry and sensitive determination of a metal complex azo dye using graphite paste electrode modified with Na-bentonite

Abstract

Graphite and its composites have gained considerable attention in electrochemical applications due to their excellent structural, electrical and chemical properties. In this study, a graphite paste electrode (GPE) modified with natural Na-bentonite (BGPE) is fabricated and utilized for the sensitive determination of Lanaset Red G (LRG) which is a kind of azo containing metal complex dye. The BGPE shows excellent enhancement in peak currents as compared to that of the GPE. The detection limit of LRG is determined to be as low as 0.65±0.08 when utilizing the BGPE as the working electrode in square wave voltammetry experiments (SWV). The electrochemical behavior of LRG is also investigated using a cyclic voltammetry (CV) technique to propose reaction mechanisms. Effects of pH and scan rate on the electrochemical behavior of LRG are studied to calculate transfer coefficients, the number of protons and electrons transferred in the redox reaction. The results show that a quasi-reversible reaction occurs on the BGPE surface/electrolyte interface. The morphology and the chemical characterization of both BGPE and GPE electrodes are investigated by the atomic force microscopy (AFM) technique and the diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), respectively.