This paper reports on the preparation and evaluation by gas chromatography with mass spectrometry for the detection of regioisomers in order to resolve derivatives.
A series of regioisomeric dimethoxyphenethylamines have a mass spectra essentially equivalent to the drug substance 2,5-dimethoxyphenethylamine (2,5-DMPEA). These substances have a molecular weight of 181, and major fragment ions in their electron ionization mass spectra at m/z 151/152. The trifluoroacetyl, pentafluoropropionyl, and heptafluorobutryl derivatives of these primary amines were prepared and evaluated by gas chromatography with mass spectrometry detection (GC–MS). The mass spectra for these derivatives do not show unique fragment ions to allow the specific identification of a particular isomer. Thus, GC–MS does not provide for the confirmation of identity of any one of the six isomers to the exclusion of the other five compounds. However, GC–MS does divide the compounds into two groups depending on the mass of the base peak. GC with infrared detection provides direct confirmatory data for the identification of 2,5-DMPEA from the other regioisomers involved in the study. Perfluoroacylated derivatives of the six regioisomeric dimethoxyphenethylamines were successfully resolved via capillary GC on a non-polar stationary phase consisting of 50 percent phenyl and 50 percent methyl polysiloxane (Rxi-50). (Published Abstract Provided)