Estimation of optically active methamphetamine and amphetamine using alpha-methoxy-alpha-trifluoromethylphenylacetyl chloride.

A simple analytical method for determination of optically active amphetamine and methamphetamine using (+)-alpha-methoxy-alpha-trifluoromethylphenylacetyl chloride (MTPA-Cl) was developed. The method was found to be useful for determining the absolute configuration and optical purity. The results obtained using the capillary GC method agreed well with those of the NMR method. The absolute configuration for illegally used methamphetamine was the (S) form and its optical purity was greater than 99% enantiomeric excess. Racemic amphetamine was found to be resolved into optically active (S)-methamphetamine by barley roots.