Determination of Cortisol and Cortisone in Human Saliva Using Dispersive Liquid-liquid Microextraction Coupled to HPLC Analysis

We examined the determination of cortisol and cortisone in human saliva with dispersive liquid-liquid microextraction (DLLME) coupled to HPLC/UV detection. In this study, by adding a mixture of acetonitrile (disperser solvent) and 1,1,2,2-tetrachloroethane (extraction solvent) into the sample, DLLME was performed. The resulting sedimented phase was injected into a reversed-phase HPLC column using a mixture of water, acetonitrile, and trifluoroacetic acid as a mobile phase for isocratic elution, and the analytes were determined with an ultraviolet detector at 254 nm. The enrichment factors of this method were ca. 20 and 40 for cortisol and cortisone, respectively, and the limits of detection were 0.30 ng mL(-1) and 0.20 ng mL(-1), respectively. We showed that the proposed method can be used to analyze trace amounts of cortisone in human saliva samples with sufficient sensitivity.