Liquid-chromatographic study of fluorescent materials in uremic fluids

Using reversed-phase "high-performance" liquid chromatography with fluorescence detection, we separated and identified some naturally fluorescent compounds in uremic serum and hemodialysate from patients with chronic renal disease. Several of the naturally fluorescent compounds were identified as indole derivatives by co-chromatography with authentic standards. In one specific case, the identity was confirmed by an enzymic peak-shift method. Compounds identified included indican, kynurenic acid, tryptophan, and 5-hydroxy-indole-3-acetic acid. Comparison of normal and uremic serum showed that the fluorescent materials are present in significantly greater concentrations in samples from uremic patients.