Determination of 5-hydroxyindoleacetic acid in urine by high-performance liquid chromatography: a fully automated method

High-performance liquid anion-exchange chromatography is combined with continuous flow spectrofluorometry at an optimalized pH for the determination of 5-hydroxyindoleacetic acid (5-HIAA) in urine. Its chief advantages are speed (7 min per determination), enabling measurement of large series of samples, precision (coefficient of variation = 0.72%), sensitivity (detection limit: 1 pmol) and specificity (no interference with 5-HIAA precursors or with the drugs tested). Reference values ( n = 112) are 25 ± 20 μmol per 24 h. Comparison with a reference spectrofluorometric technique shows a correlation coefficient of 0.96.