Determination of Norfloxacin by square-wave adsorptive voltammetry on a glassy carbon electrode

The adsorptive and electrochemical behavior of norfloxacin on a glassy carbon electrode were investigated by cyclic and square-wave voltammetry. Cyclic voltammetric studies indicated that the process was irreversible and fundamentally controlled by adsorption. To obtain a good sensitivity, the solution conditions and instrumental parameters were studied using square-wave voltammetry. In acetate buffer of pH 5.0, norfloxacin gave a sensitive adsorptive oxidative peak at 0.920 V (versus Ag-AgCl). Applicability to measurement of norfloxacin at submicromolar levels in urine samples was illustrated. The peak current was linear with the norfloxacin concentration in the range 5-50 microg ml(-1) urine. The detection limit was 1.1 microg ml(-1) urine.