Development of a urinary free cortisol assay using solid-phase extraction-capillary electrophoresis

Lokinendi V. Rao, John R. Petersen, Michael G. Bissell, Anthony O. Okorodudu, Amin A. Mohammad

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


In clinical practice, the measurement of urinary free cortisol (UFC) provides the most sensitive and specific diagnostic information for excess adrenal production of cortisol. The existing methodologies (RIA and HPLC) are time consuming, costly, involve tedious extractions, derivatizations and problems with non-specific interactions with cortisol metabolites in urine. In the present study, we describe the development of an SPE-CE method for the rapid analysis of UFC. UFC was concentrated using SPE C18 cartridges (3M Empore) under a vacuum and eluted with acetonitrile-SDS. The use of 10% acetone to wash cartridges before final elution with acetonitrile-SDS showed significant improvements in the free cortisol recovery. The complete extraction was accomplished in 10-15 min with a recovery of 89-94%. CE analysis was done on a Beckman P/ACE 5010 with detection at 254 nm using a neutral capillary. Detection limits of free cortisol in urine was improved to 10 μg/l with SPE compared to 500 μg/l without SPE. No interferences either from BSA or other urinary cortisol metabolites affected the free cortisol determinations. The results showed the feasibility of a rapid UFC detection with improved sample handling capacity. Copyright (C) 1999.

Original languageEnglish (US)
Pages (from-to)123-128
Number of pages6
JournalJournal of Chromatography B: Biomedical Sciences and Applications
Issue number1
StatePublished - Jun 25 1999


  • Cortisol
  • Steroids

ASJC Scopus subject areas

  • General Chemistry


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