Two-dimensional gas chromatography for the enantiomeric separation of ephedrine and phenaminum and their metabolites.

Two-dimensional gas chromatography was used for enantiomeric separation of ephedrine, phenaminum and their metabolites in human urine. The main column was coated with a 2,6-di-O-pentyl-3-O-trifluoroacetylated-alpha-cyclodextrin and an SE-54 phase column was used as precolumn. The results showed that two-dimensional chromatography could greatly simplify the sample preparation, eliminate the interference of sample matrices, and improve the resolution of the enantiomers of interest.