Evaluation and optimisation of separation buffers for the determination of corticosteroids with micellar electrokinetic capillary chromatography (MECC)

Separation buffers for the determination of the corticosteroids cortisone, hydrocortisone, prednisone and prednisolone with micellar electrokinetic chromatography were developed with respect to separation efficacy and the migration times, depending on the type and the concentration of the organic modifier acetonitrile as well as on the addition of gamma-cyclodextrin. The buffer containing 50 mM SDS and 16% (v/v) acetonitrile enables the rapid profiling of prednisolone together with cortisone and prednisone. Addition of gamma-cyclodextrin alters the elution sequence, but does not further enhance resolution of the corticosteroids. Baseline separation at long migration times for cortisone, hydrocortisone, prednisone and prednisolone is achieved with a buffer containing 50 mM each of SDS, dehydrocholic acid sodium salt and glycodeoxycholic acid sodium salt. (C) 1998 Elsevier Science B.V. All rights reserved.