Determination of serum corticosteroids by mixed micellar electrokinetic capillary chromatography with sodium dodecyl sulfate and sodium cholate

Abstract
The application of mixed micellar electrokinetic capillary electrochromatography to the determination of the corticosteroid hormones cortisone, cortisol (hydrocortisone), and dexamethasone in serum samples is demonstrated. The serum samples were enzymatically hydrolyzed, precipitated, solid-phase extracted, and analyzed by capillary electrophoresis. A micellar system of sodium dodecyl sulfate and sodium cholate buffered with an organic compound provided the electrolyte solution. Spiked blank serum samples were used for the linearity testing and limits of detection and quantitation were measured. Patient samples were analyzed and the concentrations of cortisol and cortisone were measured. The method, which was fast and easy to perform, was confirmed to be useful for the determination of corticosteroids in serum.