Gas chromatography of 5-hydroxy-3-methylindole in human urine.

Electron capture gas chromatography was used to estimate the urinary 5-hydroxy-3-methylindole in epileptic patients and normal controls. The urine was filtered, concentrated in vacuo, extracted into benzene-ethanol and passed through a silica gel column. The dried eluate was dissolved in acetonitrile, tri-fluoroacetylated and estimated by gas chromatography as di-trifluoroacetylated 5-hydroxy-3-methylindole. This structure was confirmed by gas chromatography-mass spectrometry. 5-Hydroxy-3-methylindole was excreted at high concentrations in some epileptics and at low concentrations in normal control subjects.