Quantitative determination of amphetamine and alpha-phenylethylamine enantiomers in judicial samples using capillary gas chromatography.

alpha-Phenylethylamine was recently reported by us in various samples seized from the illicit drug circuit. At first, alpha-phenylethylamine was identified in powders that generally contained amphetamine and caffeine. Then, a couple, who were known drug users, was found dead in their apartment. Urine samples from both victims contained large amounts of amphetamine and alpha-phenylethylamine. All of the positive samples were re-examined with gas chromatography to determine the chirality of the detected drug or drugs. The homochiral derivatizing reagent N-trifluoroacetyl-L-prolyl chloride was used to convert the drug enantiomers into their corresponding diastereomeric derivatives. These derivatives were separated on an achiral stationary phase and detected using either flame ionization detection (FID) or on-line Fourier-transform infrared spectrometry (FTIR) for quantitative or qualitative purposes, respectively. Excellent separation was realized between all diastereomeric derivatives, and interference of excess, nonvolatile derivatizing reagent was reduced to a minimum. All powder samples consisted of racemic mixtures for alpha-phenylethylamine and for amphetamine. The urine samples also contained both enantiomers of alpha-phenyl ethylamine and amphetamine, albeit in varying proportions. These findings again substantiate the synthetic origin of alpha-phenylethylamine, attributing its presence in the urine of both victims to intentional or accidental intake. The disproportionate isomeric composition found in the urine samples confirms previous reports of a stereoselective metabolism for amphetamine enantiomers and suggests a similar pharmacokinetic profile for alpha-phenylethylamine.