Identification of endogenous and exogenous glucocorticoids by HPLC-MS in human urine
2010
Dikunets, M. A | Appolonova, S. A | Rodchenkov, G. M
A selective and sensitive screening method for identifying 20 endogenous and exogenous corticosteroids in human urine is presented. Analysis was performed by HPLC with a mass-selective “ion trap” detector and spray ionization. Urine samples were prepared by liquid-liquid extraction (with a mixture of toluene and di-ethyl ether, 50:50 v/v). The dry residue was redissolved in 50 μl of methanol and aliquots of 5 μl were loaded onto the HPLC-MS system. Chromatographic separation was performed on a Restek Ultra C18 (2.1 × 100 mm, 5 μm) column. The mobile phase was a solution of 0.05% formic acid containing 20 mM ammonium acetate pH 3 (A) and acetonitrile (B). The detection limits for all corticosteroids were 1 - 3 ng/ml. Chromatographic separation and mass spectrometric data for identification of mixtures of steric isomers of betamethasone and dexamethasone are presented.
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