AUTOMATED-DETERMINATION OF AMPHETAMINE ENANTIOMERS USING A 2-DIMENSIONAL COLUMN-SWITCHING CHROMATOGRAPHIC SYSTEM FOR DERIVATIZATION AND SEPARATION

A method for the on-line quantification of amphetamine enantiomers was developed. The assay uses a 20 mm X 2.1 mm id pre-column packed with a Hypersil C-18 (30 mu m) material for purification and derivatization of the analytes and a mixture of o-phthaldialdehyde and N-acetyl-L-cy steine as derivatizing reagent, The resulting derivatives were subsequ ently separated in a conventional C-18 achiral column using a mobile p hase of acetonitrile-methanol-acetate buffer (6 + 48 + 46 v/v), and de tected by fluorescence. Under optimized conditions, the system provide d average responses of 88 +/- 3 and 87 +/- 3% compared with those of t he analogous solution derivatization for the L- and D-amphetamine enan tiomers, respectively. The method shows good linearity and reproducibi lity in the 0.25-10.0 mu g ml(-1) concentration range, The limits of d etection mere 50 ng ml(-1) for both isomers. The method was applied to the quantification of amphetamine enantiomers in pharmaceuticals and urine samples.