Indole derivatization procedures for electron capture negative chemical ionization mass spectrometry: identification of 1-methyl-1,2,3,4-tetrahydro-beta-carboline in rat brain and lung.

Procedures have been developed for the isolation of pharmacologically active indole compounds from biological samples and for the introduction of electron-capturing groups, pentafluorobenzyl and trifluoroacetyl, onto the indole nitrogen atom. The resulting derivatives have good gas chromatographic properties and strong electron affinities which make them highly suitable for detection by electron capture negative chemical ionization mass spectrometry. These procedures were used to identify 1-methyl-1,2,3,4-tetrahydro-beta-carboline as a component of rat brain and lung.