Collect. Czech. Chem. Commun. 2002, 67, 1-9

Mass Fragmentography of Cortisol and Cortisone: Preliminary Studies on the Development of a Reference Method

Hugh L. J. Makina,*, David J. H. Trafforda and Norman F. Taylorb

a Department of Clinical Biochemistry, St. Bartholomew's & the Royal London School of Medicine & Dentistry, London E1 2AD, U.K.
b Department of Clinical Biochemistry, King's College School of Medicine, Denmark Hill, London SE5 9RS, U.K.


Cortisol and cortisone are the two main glucocorticoids found in human plasma. Cortisol is commonly measured as a means of assessing adrenal function, usually by immunoassay, but such procedures must be subject to proper quality control which ideally uses analyte target values measured by isotope dilution mass fragmentography (GC-MS). Three derivatives of these steroids have been investigated for their chromatographic and mass spectral characteristics in order to develop a simple and rapid GC-MS method for this purpose. Trimethylsilyl ether-O-methyloxime derivatives gave poor sensitivity and the syn- and anti-isomers were resolved into two peaks. Cyclic methylboronate-O-methyloxime derivatives gave excellent sensitivity but were difficult to prepare, occasionally giving rise, by some unknown mechanism, to 11-oxidation of cortisol. The underivatised 11-hydroxyl of this derivative of cortisol also gave rise to chromatographic problems. Enol-trimethylsilyl ethers however were easy to prepare and gave excellent sensitivity (10-17 times that achieved with the trimethylsilyl ether-O-methyloxime derivatives). Straight line calibration graphs were obtained and the method gave clean traces allowing high specificity and sensitive measurement of cortisol and cortisone in human plasma using tri-deuterated cortisol as an internal standard.

Keywords: Steroids; Mass spectrometry; Glucocorticoid hormones; Analytical methods; GC-MS.

References: 13 live references.