부산대학교 도서관

A simple fluorometric method has been developed for determining urinary free cortisol or corticosteroids. The procedure is as follows: Extract 2ml of urine with 2ml of dichloroethane, wash the organic layer once with 0.5ml of water and twice with 0.5ml of 0.1N NaOH, mix 0.2ml of the organic layer with ethanol-conc. H2SO4 (3:7, v/v), stand it for 40min, and then perform fluorometry (λex=468nm, λem=520nm).This method was compared with an isotope dilution method and other methods for the determination of urinary free cortisol or corticosteroids. The values obtained by the present method, dichloroethane extraction-fluorometry, showed good correlation with those by the isotope dilution method and dichloromethane extraction-RIA, and were coincident well with those by the latter two methods. A common method, dichloromethane extraction-fluorometry, showed good correlation with the present method but gave apparently high values. Application of RIA to unextracted urine gave three times the values assayed by the present method.Thus, this method is suitable for a routine laboratory test for urinary free cortisol from the view point of simplicity, accuracy and precision.