Anodic Adsorptive Voltammetric Determination of Norfloxacin Using Carbon Paste Electrode

A highly selective and rapid anodic adsorptive voltammetric method was developed for the determination of trace amounts of Norfloxacin by using a carbon paste electrode (CPE). The Norfloxacin was adsorbed on the surface of the CPE in a medium of 0.40 mol·L-1 NH4OAc-HOAc buffer (pH 4.51) yielding an oxidation peak at 1.16 V (vs.SCE). The linear relationship between the peak current and Norfloxacin concentration was found in the range of 4.0×10-9~4.0×10-7mol·L-1 with correlation coefficient of 0.996. The detection limit was found to be 1.0×10-9mol·L-1 (S/N=3) with acummulation for 110 s. Mechanism of the electrode reaction was discussed. The proposed method has been applied to the direct determination of trace amounts of Norfloxacin in urine samples with RSD′s less than 4%,and recoveries in the range of 99.1%-104.0%.