Method development for cortisol and cortisone by micellar liquid chromatography using sodium dodecyl sulphate: application to urine samples of rugby players.

The chromatographic behavior of cortisol and cortisone using a micellar medium of sodium dodecyl sulphate (SDS) as surfactant, a Hypersil C18 (150- x 3.2-mm i.d., 5 microm) column, a flow rate of 0.5 mL/min, and UV absorbance detection at 245 nm is described. The effect of several organic modifiers and the surfactant concentration on the separation is studied. A mobile phase of 18 mM SDS and 8.3% tetrahydrofuran allows for the separation of cortisol and cortisone up to baseline. These results are also achieved by applying a bivariant optimization method. The proposed method is sensitive, reproducible, and selective. In addition, it is less expensive than conventional high-performance liquid chromatography methods for cortisol and cortisone. The method is applied to the determination of cortisol and cortisone in urine samples of rugby players before and after stress for doping control purposes.