Comparison of the separation of nine tryptamine standards based on gas chromatography, high performance liquid chromatography and capillary electrophoresis methods

Nine tryptamines, including α-methyltryptamine (AMT), N,N-dimethyltryptamine (DMT), 5-methoxy-α-methyltryptamine (5-MeO-AMT), N,N-diethyltryptamine (DET), N,N-dipropyltryptamine (DPT), N,N-dibutyltryptamine (DBT), N,N-diisopropyltryptamine (DIPT), 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), and 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT) were selected as model compounds. Comparisons of their sensitivity, selectivity, time, cost and the order of migration are described based on different separation techniques (GC, HPLC and CE, respectively). As a result, the limit of detection (S/N = 3) obtained by GC/MS and LC/UV-absorption ranged from 0.5 to 15 μg/mL and 0.3 to 1.0 μg/mL, respectively. In contrast to this, based on the CZE/UV-absorption method, the limit of detection (S/N = 3) was determined to 0.5–1 μg/mL. However, when the sweeping-MEKC mode was applied, it dramatically improved to 2–10 ng/mL. In the case of GC, HPLC and CE, migration times of the nine standards ranged from 11 to 15 min and 8 to 23 min by GC and HPLC, respectively; ranged from 20 to 26 min by sweeping-MEKC. The order of migration of DMT, DET, DPT and DBT follows the molecular weight, whereas the order of migration of AMT and 5-MeO-AMT (primary amines), DIPT (an isomer of DPT) and 5-methoxy-tryptamines (5-MeO-AMT, 5-MeO-DMT and 5-MeO-DIPT) can be altered by changing the separation conditions.