Simultaneous assay of corticosterone and cortisol in plasma by reversed-phase liquid chromatography.
We have developed a simple, specific, and sensitive reversed-phase liquid-chromatographic method for accurate and simultaneous analysis of corticosterone and cortisol in human plasma. We achieved a detection limit of 300 ng/L for both steroids by modifying the old solid-phase extraction method to make use of "Tef Elutor" C18 columns, using a minibore (100 x 2 mm) analytical column, and using an ultraviolet detector with a 10-mm-pathlength flow cell. With the new extraction method absolute extraction efficiencies were greater than 90% for all the analytes, including the internal standard, flumethasone. The mobile phase was water (containing 5 mL of triethylamine per liter and citric acid to adjust the pH to 6.5), tetrahydrofuran, and acetonitrile (82/10/8 by vol). The average interassay CV for corticosterone at 0-25 micrograms/L was 6.5%; that for cortisol at 0-300 micrograms/L was 3.8%. The analytical recovery relative to the internal standard was 100.2% for cortisol and 102.6% for corticosterone. Possible interferences from drugs and other steroids were studied.
Hariharan
M
M
University of Michigan Medical School, Department of Psychiatry, Ann Arbor 48109-0656.
Naga
S
S
VanNoord
T
T
Kindt
E K
EK
D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000706:statistics & numerical data; D003345:Corticosterone / Q000097:blood*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D011786:Quality Control
D003345:Corticosterone; D006854:Hydrocortisone