Electrochemical Behaviour of the Antibiotic Drug Novobiocin Sodium on a Mercury Electrode

Abstract

In this paper, electrochemical and adsorption behaviors of the antibiotic drug novobiocin sodium in 0.04 mol dm-3 Britton-Robinson buffers (pH = 2-12) at a hanging mercury drop electrode have been studied by means of cyclic voltammetry, square-wave voltammetry and square-wave adsorptive stripping voltammetry techniques. In 0.04 mol dm-3 Britton-Robinson buffers, novobiocin sodium has developed an irreversible cathodic wave over the pH range 5-12. The variation of the potential and/or current of reduction signal with pH of the supporting electrolyte and instrumental variables such as scan rate, frequency, pulse height and deposition time have been studied. Novobiocin exhibits an adsorption characteristic due to its adsorption phenomena. It has been also found that the adsorption of novobiocin on the electrode surface depends predominantly on the pH of the supporting electrolyte. Since the electrode reaction mechanism of novobiocin sodium has been firstly discussed, a mechanism is proposed for the reduction process. At the mercury electrode, the reduction of novobiocin sodium has been probably carried out by means of the attack of hydroxyl ion to the coumarin moiety in the molecular structure and then the consumption of two electrons.