Square-wave voltammetric behaviour and automated determination of cephalothin by a novel sample handling approach.

Abstract

The voltammetric behaviour of the cephalosporin cephalothin has been studied by rapid-scan square-wave voltammetry at single mercury drops and at the static mercury drop electrode (SMDE). A study of the variation of the peak current with solution variables such as pH, supporting electrolyte, concentration of cephalothin and instrumental variables such as scan speed, pulse width, pulse height and delay time has resulted in optimisation of the reduction signal for analytical purposes. This reduction signal can be used to monitor the degradation of cephalothin in acidic and basic media, and has also been applied to the rapid, accurate and precise determination of cephalothin in a pharmaceutical preparation using an automated sampling handling approach controlled by a polarographic analyser. Concentrations of cephalothin in the range 10–7–10–8M can be determined using this automated approach and involving rapid-scan square-wave voltammetric determination after adsorptive accumulation of cephalothin at the SMDE. The applicability of this latter technique to the determination of cephalothin in body fluids is assessed.