Simultaneous Separation and Detection of 18 Phenethylamine/Tryptamine Derivatives by Liquid Chromatography–UV Absorption and –Electrospray Ionization Mass Spectrometry

Abstract

The optimal conditions for the separation and detection of a mixture of 18 phenethylamine/tryptamine derivatives were determined, using liquid chromatography/UV-absorption (LC/UV) and liquid chromatography/electrospray ionization mass spectrometry (LC/ESI MS) methods, respectively. Complete separation could be achieved within ~25 min using gradient elution (A, 0.1% formic acid aqueous solution/pH 2.5; B, acetonitrile). The limit of detection (LOD at S/N = 3) obtained by LC/UV-absorption (absorption wavelength, 280 nm) was in the range from 0.3 to 3 mg/mL. In contrast, when the LC/ESI MS method was used, the LODs for primary, secondary and tertiary amines were in the ranges 0.1 -3.0, 0.1 -0.2, and 0.05 -1.8 mg/mL, respectively. The lower LOD obtained for a tertiary amine can be attributed to the fact that its ionization efficiency (during the ESI process) is better than the others. In order to improve the LOD of a primary/secondary amine, a derivatization procedure was used in which the chemical structure was altered to a secondary/tertiary amine, via a reaction with acetic anhydride. As a result, the LODs for primary/secondary amines could be significantly improved. The characteristic mass fragmentations of the 18 phenethylamine/tryptamine derivatives, as well as the products of the reaction with acetic anhydride, were investigated, and the data were reported. A urine sample was obtained by spiking urine from a volunteer with the 18 derivatives, and after liquid-liquid extraction the sample was examined by LC/UV and LC/ESI MS, respectively. The extraction procedures used for the urine sample and the experimental conditions for the separation and detection were optimized.

Test purchase of new synthetic tryptamines via the Internet: Identity check by GC-MS and separation by HPLC

“…There are articles dealing with similar separation techniques of tryptamine derivatives but they report on gradient elution which is more complex (Hsiao et al, 2009;Wang et al, 2008). A further benefit of the present method is the opportunity to distinguish between the two isomeric compounds AMT and 5-API.…”

“…Hsiao and co-workers reported on the simultaneous separation and detection of phenetylamine and tryptamine derivatives using HPLC-UV and LC/ESI MS (Hsiao et al, 2009).…”