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PubMed · 16158300

A fluorimetric assay for cortisol.

Daniel Appel·Rolf D Schmid·Calin-Aurel Dragan·Matthias Bureik·Vlada B Urlacher
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Abstract

A simple, rapid and sensitive fluorimetric assay for the quantitative determination of cortisol is reported. The assay is based on the formation of a fluorescent dye when cortisol is incubated with a mixture of sulfuric acid and acetic acid. The fluorescence spectrum recorded for the resulting dye shows a maximum extinction at 475 nm and a maximum emission at 525 nm. The solvent 2-methyl-4-pentanone was used for extraction and was found to act as a fluorescence amplifier. A limit of detection of 2.7 muM was achieved, making it possible to forego solvent evaporation. The assay suffers minor interference from 11-deoxycortisol which exhibits low fluorescence at lambda (ex): 460 nm; lambda (em): 505 nm. Typical standard deviations were below 4%. We validated the assay using a biotransformation with recombinant Schizosaccharomyces pombe which regioselectively hydroxylates 11-deoxycortisol to cortisol. The method described herein is suitable for preliminary screening of microorganisms capable of steroid hydroxylation.

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BiotransformationCortodoxoneFluorescent DyesFluorometryHydrocortisoneHydroxylationModels, ChemicalPentanonesReproducibility of ResultsSchizosaccharomycesSolventsSpectrometry, FluorescenceSteroidsJournal ArticleResearch Support, Non-U.S. Gov't

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Daniel Appel, Rolf D Schmid, Calin-Aurel Dragan, Matthias Bureik, Vlada B Urlacher. 2005-10-12. A fluorimetric assay for cortisol.. https://doi.org/10.1007/s00216-005-0022-9

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