Rapid determination of amphetamine stereoisomer ratios in urine by gas chromatography-mass spectroscopy.

We describe a method for the determination of amphetamine optical isomer ratios. A simple basic extraction of amphetamine from urine is followed by on-column derivatization with (S)-(-)-N-(trifluoroacetyl)-L-prolyl chloride and analysis by gas chromatography-mass spectroscopy. This approach has been shown to be satisfactory for the separation of d- and l-amphetamine isomers and precision data shows the method to be reproducible. Patient data is presented to demonstrate the ability to differentiate between patients taking d-amphetamine and those using illicit (racemic) amphetamine by their l/d amphetamine ratio.