Surface Modified Electrodes Used In Cyclic Voltammetric Profiling Of Quinine An Anti - Malarial Drug

Abstract

In this paper electrochemical profiling of quinine, an effective anti - malarial drug administered to humans, was done using primarily the very versatile el ectrochemical technique - cyclic voltammetry. In the electro - analysis, the main supporting electrolyte used was sulphuric acid. The surface of the working electrode was modified using electronically conducting polymer - polyanailine and a clay montmorillonit e - bentonite. Quinine and metal cation Cu 2+ , Co 2+ , Zn 2+ and Sn 2+ were also used to modify the electrode surface.The results obtained showed that quinine oxidation /reduction potential on bare carbon graphite electrode occured at 0.495V/0.300V and 0.015V (0 .25M H 2 SO 4 supporting electrolyte). Bentonite modified electrode gave 0.434V/0.480V (1M H 2 SO 4 supporting electrolyte) and 0.360V/0.345V (1M HCl supporting electrolyte). A mechanistic pathway for the oxidation of quinine has also been proposed. It was also observed from the results obtained from studies on the effect of consumables such as tea, glycine and milk on quinine, that milk totally suppressed the redox process in quinine. Amino acids which are the building blocks in proteins and which is an importan t macromolecule in humans, does not affect significantly the redox process in quinine. Cyclic voltammetric profiling of quinine interaction with metal cations such as Cu 2+ , Co 2+ , Zn 2+ and Sn 2+ and drugs such as paracetamol, acetyl salicylic acid, hydroco rtisone and ferrous fumarate revealed interactions between the redox centers. Key Words: Surface modified electrodes, cyclic voltammetry, polyaniline, bentonite and quinine