Direct determination of methamphetamine enantiomers in urine by liquid chromatography with a strong cation-exchange precolumn and phenyl-beta-cyclodextrin-bonded semi-microcolumn

Methamphetamine enantiomers in drug abusers' urine were clearly separated by semi-microcolumn liquid chromatography using a column-switching system. The system consists of two separation processes: firstly, a strong cation-exchange precolumn removes neutral and anionic substances in urine, and then methamphetamine enantiomers trapped in the column are transferred to and separated in a phenyl-beta-cyclodextrin-bonded semi-microcolumn (Chiral Drug, 150 mm x 1.5 mm I.D.). (S)-(+)-Methamphetamine was baseline separated from (R)-(-)-methamphetamine within 25 min, directly from urine samples. The detection limit for both enantiomers was 0.1 microg/ml.