Multi-matrix assay of cortisol, cortisone and corticosterone using a combined MEPS-HPLC procedure

The development and validation of a bioanalytical assay for the simultaneous determination of cortisol, cortisone and corticosterone levels in several matrices, such as saliva, plasma, blood and urine samples have been described. The method is based on a rapid test which combines a microextraction by packed sorbent procedure and liquid chromatography-diode array technique. Chromatographic separation of the analytes (cortisol, cortisone and corticosterone) and the internal standard (methylprednisolone) was achieved in less than 10min on a reversed-phase pentafluorophenyl column using a mobile phase composed of phosphate buffer and acetonitrile. The assay was performed after an innovative microextraction procedure by means of C8 sorbent which guaranteed good clean-up of the matrices and satisfactory extraction yield of the analytes. Moreover, the method gave linear results over a range of 5-100ngmL(-1) and showed good selectivity and precision. This method was successfully applied for quantifying corticosteroids in specific matrices derived from some healthy volunteers in comparison to two socially diversified groups, namely former heroin addicts undergoing opioid replacement therapy and poly-drug abusers.