Separation and simultaneous determination of nalidixic acid, hydroxynalidixic acid and carboxynalidixic acid in serum and urine by micellar electrokinetic capillary chromatography.

T Pérez-Ruiz, C Martínez-Lozano, A Sanz, E Bravo

Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, Spain.

Journal of chromatography. B, Biomedical sciences and applications 1999 Mar 19

filter terms:

Separation in capillary electrophoresis is governed by various factors, including buffer type, buffer concentration, pH, temperature, voltage and micelles. Through proper adjustment of these parameters, nalidixic acid and its two major metabolites, 7-hydroxynalidixic and 7-carboxynalidixic, could be separated by micellar electrokinetic capillary chromatography using an electrophoretic electrolyte consisting of 50 mM borate buffer (pH 9) containing 25 mM sodium dodecyl sulphate and 10% acetonitrile. A linear relationship between concentration and peak area for each compound was obtained in the concentration range 0.15-100 micrograms ml-1, with a correlation coefficient greater than 0.999 and detection limits in the 0.2-0.7 ng ml-1 range. Intra- and inter-day precision values of about 0.8-1.2% RSD (n = 11) and 1.3-2.0% RSD (n = 30), respectively, were obtained. The method has been applied to the analysis of nalidixic acid and its two major metabolites in serum and urine with limits of sensitivity lower than 0.8 ng ml-1.

Citation

T Pérez-Ruiz, C Martínez-Lozano, A Sanz, E Bravo. Separation and simultaneous determination of nalidixic acid, hydroxynalidixic acid and carboxynalidixic acid in serum and urine by micellar electrokinetic capillary chromatography. Journal of chromatography. B, Biomedical sciences and applications. 1999 Mar 19;724(2):319-24