Determination of quinolinic acid in human urine by liquid chromatography with fluorimetric detection

A system has been developed for the determination of quinolinic acid in human urine using liquid chromatography with fluorimetric detection. The compound is separated by reversed-phase chromatography using a 35 mM potassium dihydrogen-phosphate solution (adjusted to pH 3.8 with 0.2 M citric acid) containing 350 mM hydrogen peroxide and 0.05 mM tetramethylammonium hydroxide as a mobile phase. The compound in the column effluent is irradiated with ultraviolet light to produce fluorescence. This fluorescence is monitored with excitation at 326 nm and emission at 380 nm. The calibration graph for quinolinic acid is linear over the range 0.36–68.8 nmol ml−1 upon injecting 10 μl of the standard solution. Pretreatment of urine was achieved by dilution and filtration only. The mean recovery of quinolinic acid from urine is more than 95%.