Separation of enantiomeric ephedrine and pseudoephedrine - High pressure liquid chromatography and capillary electrophoresis

Ephedrine and pseudoephedrine (psi-ephedrine), frequently found in packaged drugs of abuse, art: common over-the-counter pharmaceuticals. Present in h igh concentrations, these compounds have reportedly caused false identifica tion of methamphetamine in urine specimens, Furthermore, (-)-ephedrine and (+)-psi-ephedrine are used for manufacturing (+)-methamphetamine. Thus, kno wledge on the enantiomeric compositions of these compounds may help identif y their sources, providing valuable information to the investigation proces s. High pressure liquid chromatography (HPLC) and capillary electrophoresis (CE) methods were evaluated and compared for their application in analyzin g the enantiomeric compositions of these two compounds. A chiral column (Su pelcosil LC-(S) Naphthyl Urea) was found effective in resolving the resulti ng four components when derivatized with both of the following two chiral d erivatization reagents: N-trifluoroacetyl-l-prolyl chloride (l-TPC) and 2,3 ,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (GITC), A C18 colu mn, although less effective, can also adequately resolve these four compone nts for identification purposes. With CE, inclusion of 30 mM hydroxypropyl- beta-cyclodextrin in 50 mM phosphate buffer (pH 2.5) was very effective in resolving all four components using an uncoated fused silica capillary with out Drier derivatization.