Fluorometric Determination of Nalidixic Acid in Human Urine Using High-Performance Liquid Chromatography with Postcolumn Photochemical Reaction

Abstract

A high-performance liquid chromatographic method involving a postcolumn photochemical reaction and fluorometric detection has been developed for the determination of nalidixic acid concentration in human urine. The mobile phase consists of 0.1 M potassium dihydrogenphosphate-sodium tetraborate buffer (pH 8.6)-methanol (75 : 25, v/v) containing 20 mM hydrogen peroxide. The compound in the column effluent is irradiated with ultraviolet light to produce fluorescence. This fluorescence is monitored with excitation at 380 nm and emission at 440 nm. The calibration curve for nalidixic acid is linear over the range of 0.2-300 ng/injection. The mean recovery from urine is nearly 100%.