Determination of serum cortisol by thermospray liquid chromatography/mass spectrometry: comparison with gas chromatography/mass spectrometry.
The determination of serum cortisol by thermospray liquid chromatography/mass spectrometry (LC/MS) has been assessed. The method incorporates stable isotope dilution and immunoadsorption extraction. [M + H]+ ions are monitored during LC/MS. The within-assay reproducibility is satisfactory (coefficient of variation 7% at a concentration of 190 ng ml-1), though inferior to that achieved with the (more lengthy) procedure of gas chromatography/mass spectrometry (GC/MS). Satisfactory agreement between LC/MS (y) and GC/MS (x) data was observed (y = 0.934x + 12.4 ng ml-1; r = 0.968; n = 14). It is concluded that the generation of precise reference data for the assessment of routine cortisol assays is at present better achieved by GC/MS. LC/MS, however, provides satisfactory quantitative data via a more simple and rapid method.
Tenovus Institute for Cancer Research, University of Wales College of Medicine, Heath, UK.
S J
SJ
Gaskell
K
K
Rollins
R W
RW
Smith
C E
CE
Parker
D002853:Chromatography, Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D013058:Mass Spectrometry
D006854:Hydrocortisone