Mass spectrometry methods—GC-EI/MS, LC-ESI/MS, and MALDI/TOFMS—were compared for analyzing 13 tryptamine and phenethylamine compounds, including AMT, DMT, 5-MeO-AMT, DET, DPT, DBT, DIPT, 5-MeO-DMT, 5-MeO-DIPT, methamphetamine, 3,4-MDA, 3,4-MDMA, and MBDB. Parent ions were difficult to obtain by GC/MS, but protonated molecular ions were clearly observed by ESI/MS and MALDI/TOFMS. Two major characteristic fragmentations occurred: alpha-cleavage (producing [3-vinylindole]+) and beta-cleavage (producing [CH2N(+)R(N1)R(N2)]). With ESI, alpha-cleavage was the major process; with MALDI, beta-cleavage dominated. The ionization efficiency and fragments from either cleavage depended on the degree of alkylation of the side chain nitrogen.
Three analytical methods—matrix-assisted laser desorption/time-of-flight mass spectrometry, gas chromatography–electron ionization–mass spectrometry, and liquid chromatography–electrospray ionization/mass spectrometry—were compared for characterizing 20 phenethylamine and tryptamine standards. For GC-EI/MS, three characteristic peaks (the molecular ion and fragments from Cβ-Cα bond breakage) uniquely identified 2C series compounds. For ESI/MS and MALDI/TOFMS, the protonated molecular ion and fragments from α-cleavage and β-cleavage provided useful information for rapid screening and confirmation of phenethylamine and tryptamine derivatives. The assay successfully determined samples containing illicit drugs.