Infrared discrimination of enantiomerically enriched and racemic samples of methamphetamine salts.

A relatively rapid and simple means of enantiomer determination is described for the determination of methamphetamine, a common drug of abuse. The method employs the well known technique of infrared transmission spectrometry on solid samples dispersed within an alkali metal halide matrix. This approach exploits the solid-state, ion-exchange reaction between methamphetamine hydrochloride and a potassium iodide matrix and the subsequent formation of the hydriodide salt in situ. The infrared properties of the hydriodide salt are distinct for enantiomerically enriched and racemic samples, and therefore are readily distinguished by infrared transmission spectrometry. This technique uses materials and instrumentation that are generally available to most crime laboratories. The applicability of this method to some other amine drugs is discussed.