High-performance liquid chromatography-electrospray ionisation-tandem mass spectrometry for the analysis of 1,2,3,4-tetrahydro-beta-carboline derivatives.

A rapid and sensitive method is described for the detection of 1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid, 1-methyl-1,2,3,4- tetrahydro-beta-carboline-3-carboxylic acid and 1-methyl-1,2,3,4-tetrahydro-beta-carboline by electrospray ionization tandem mass spectrometry coupled to liquid chromatography. In combination with selected reaction monitoring (SRM) detection limits of 3 ng ml-1 (ca. 75 fmol on column) were established by the use of model solutions. Due to the excellent selectivity and sensitivity of SRM no sample preparation step was required prior to analysis of food samples. In addition, any artifactual formation of tetrahydro-beta-carbolines could be excluded. Application of the method revealed that all food samples analyzed contained both tetrahydro-beta-carboline-carboxylic acids at ng ml-1 to microgram ml-1 concentrations, whereas 1-methyl-1,2,3,4-tetrahydro- beta-carboline was identified in most samples as a minor constituent.