DIRECT ANALYSIS OF CORTISOL AND CORTISONE IN HUMAN URINE BY SEMI-MICROCOLUMN LIQUID-CHROMATOGRAPHY WITH MIXED-FUNCTION PRECOLUMN

A column-switching system based on semi-microcolumns is constructed for direct analysis of cortisol and cortisone in human urine samples. Urine samples (100 mu l) were directly injected into a polymer-coated mixed-function (PCMF) column (35 mm x 1.5 mm i.d.), which removes proteins and fractionates an analyte-containing zone. The analyte-containing fraction was thereafter transferred to a C18 semi-microcolumn (250 mm x 1.5 mm i.d.). The analytes were monitored with ultraviolet (UV) absorption at 242 nm, with the detection limit for cortisol and cortisone, 3 pmol/mL (at a S/N ratio of 5) for each. The system showed quantitative results for dilute standard samples using human urine as a solvent. The method could be applied to the routine assessment of cortisol and cortisone in human urine. (C) 1995 John Wiley & Sons, Inc.