Differentiation of betamethasone and dexamethasone using liquid chromatography/positive electrospray tandem mass spectrometry and multivariate statistical analysis.
Betamethasone and dexamethasone are two corticosteroids differing in the stereoisomery of their C-16 methyl group. These two compounds are imperfectly separated by reversed-phase liquid chromatography and their mass spectra are very similar, leading to a difficult unambiguous identification according to European criteria. A method is proposed for differentiating betamethasone and dexamethasone using liquid chromatography/tandem mass spectrometry and multivariate statistical analysis. Multiple analysis of variance was used for the justification and the selection of diagnostic ions. Principal component analysis permitted the suitability of the approach to be tested on a large number of samples. Discriminant factorial analysis was finally performed to build a decisional model based on the six most significant ions. This novel utilization of mass spectrometric data appeared efficient for the unambiguous identification of the target analytes in urine samples.
Antignac
Jean-Philippe
JP
Laboratoire d'Etude des Résidus et Contaminants dans les Aliments (LABERCA), Ecole Nationale Vétérinaire de Nantes, BP 50707, 44307 Nantes Cedex 3, France. laberca@uet-nantes.fr
Le Bizec
Bruno
B
Monteau
Fabrice
F
Andre
François
F
D000818:Animals; D001623:Betamethasone / Q000032:analysis* / Q000652:urine; D002417:Cattle; D002853:Chromatography, Liquid; D003907:Dexamethasone / Q000032:analysis* / Q000652:urine; D007202:Indicators and Reagents; D015999:Multivariate Analysis; D021241:Spectrometry, Mass, Electrospray Ionization
D007202:Indicators and Reagents; D003907:Dexamethasone; D001623:Betamethasone