title: [GC-MS determination of l-ephedrine and d-pseudoephedrine in human plasma].
abstract: To determine l-ephedrine (E) and d-pseudoephedrine (PE) concentrations in human plasma simultaneously, we used a selected-ion monitoring method with gas chromatography-mass spectrometry (GC-MS) using deuterium-labeled E and PE as internal standards. The E and PE in human plasma were extracted with hexane-ethylacetate (9/1) under alkaline conditions and were easily converted into their heptafluorobutyryl derivatives by treating with heptafluorobutyrylimidazole. The calibration curves of E and PE showed a good linearity in the range from 0.82 to 81.9 ng/ml for E, and from 0.41 to 41.0 ng/ml for PE, respectively. The limit of detection was 0.82 ng/ml for E and 0.41 ng/ml for PE in human plasma, respectively.
authors.affiliation: Kampo and Healthcare Research Laboratories, Kanebo, Ltd., Osaka, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Nakano
authors.forename: Y
authors.initials: Y
authors.lastname: Morimoto
authors.forename: S
authors.initials: S
authors.lastname: Tajima
authors.forename: N
authors.initials: N
authors.lastname: Kosaka
mesh_terms: D004809:Ephedrine / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D015203:Reproducibility of Results; D013237:Stereoisomerism
chemical_list: D004809:Ephedrine