title: Automated liquid chromatographic determination of the 20-dihydro isomers of cortisol and cortisone in human urine.
abstract: A fully automated method for the simultaneous assessment of cortisol, cortisone and their 20-dihydro isomers in human urine is described. On-line sample enrichment, prepurification, focusing and injection are combined with automated high-performance liquid chromatographic separation and quantification. Losses of steroids throughout the total procedure are negligible. Thus, external calibration is feasible for quantification. Coefficients of variation range between 8.7 and 17.0% for inter-assay variability and between 1.3 and 5.2% for intra-assay variability. Assay sensitivity is 15 nmol/l. In normal students, the medians of the relative excretion rates of free 20 alpha-dihydrocortisol, 20 alpha-dihydrocortisone, 20 beta-dihydrocortisol and 20 beta-dihydrocortisone were 10.9, 6.1, 7.7 and 4.4 mumol/mol creatinine. The fully automated feature renders the present method well suited for routine diagnosis of hypercorticoidism.
mesh_terms: D001322:Autoanalysis; D002853:Chromatography, Liquid; D003348:Cortisone / Q000031:analogs & derivatives* / Q000652:urine; D006801:Humans; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000652:urine*; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet
chemical_list: D012997:Solvents; C016499:20-hydroxycortisol; D003348:Cortisone; D006854:Hydrocortisone