[Point of micropreparative high pressure liquid chromatography and thin-layer chromatography for the identification of indole compounds in human plasma (author's transl)].

Results are presented on the analysis of indolic metabolites of tryptophan in human plasma, using high-pressure liquid chromatography and thin-layer chromatography. Dichloromethane/ethanol extracts of denaturated plasma were analysed. Thin-layer chromatography proved to be more advantageous for the analysis of this class compounds because it is possible to use a specific staining reagent (4-dimethylaminobenzaldehyde). The advantage of high-pressure liquid chromatography lies in the rapid isolation and purification of unknown compounds for identification in an off-line method. This application is demonstrated with the isolation of N-acetyltryptophan from human plasma. Preliminary results are presented on the plasma concentration of indole-3-lactic acid, indole-3-acetic acid and N-acetyltryptophan in healthy persons, phenylketonurics, and uremic patients.