Electrochemical sensor for the sensitive determination of norfloxacin in human urine and pharmaceuticals

Electrochemical determination of Norfloxacin (NF) has been presented at edge plane (EPPGS) and basal plane pyrolytic graphite sensors (BPPGS) by using square wave voltammetry at physiological pH 7.2. An increased peak current with a shift of peak potential to less positive value was observed at EPPGS as compared to BPPGS. The effect of pH, scan rate and analyte concentration has been examined. The peak current was found to be linear to the concentration of NF in the range 0.5 x 10(-6) to 50.0 x 10(-6) mol L(-1) for EPPGS and the detection limit (3 sigma/b) was found to be 28.3 x 10(-8) mol L(-1). The method has been successfully used to determine the content of NF in the pharmaceutical preparations. Biological relevance of the developed method has been described by the determination of NF in human urine samples of the patients undergoing treatment with NF. The method is selective and NF can be determined without any interference from common urine metabolites such as uric acid and ascorbic acid. (C) 2011 Elsevier B.V. All rights reserved.