Determination of corticosteroids in plasma by high-performance liquid chromatography after pre-column derivatization with 2-(4-carboxyphenyl)-5,6-dimethylbenzimidazole.
2-(4-Carboxyphenyl)-5,6-dimethylbenzimidazole (CDB) was used as a pre-column derivatization reagent for corticosteroids analysed by high-performance liquid chromatography with fluorimetric detection. Eight corticosteroids were derivatized with CDB to their esters in acetonitrile containing 4-piperidinopyridine and 1-isopropyl-3-(3-dimethylaminopropryl)carbodiimide perchlorate. The resulting CDB esters were extracted with a Sep-Pak C18 cartridge and the esters were separated on a reversed-phase column (Zorbax ODS) with water-methanol (25:75, v/v) containing 5 mmol/l tetramethylammonium hydrogensulphate as the mobile phase. The limits of detection for steroids were 0.06-0.3 pg per 100 microliters of plasma (signal-to-noise = 3). The within-day relative standard deviations (n = 6) were 7.8-11.1%, and day-to-day relative standard deviations (n = 6) were 7.0-10.4%.
Katayama
M
M
Meiji College of Pharmacy, Tokyo, Japan.
Masuda
Y
Y
Taniguchi
H
H
D000305:Adrenal Cortex Hormones / Q000097:blood*; D001562:Benzimidazoles; D001565:Benzoates; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D004024:Dicyclohexylcarbodiimide; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D012997:Solvents; D013050:Spectrometry, Fluorescence
C080307:2-(4-carboxyphenyl)-5,6-dimethylbenzimidazole; D000305:Adrenal Cortex Hormones; D001562:Benzimidazoles; D001565:Benzoates; D007202:Indicators and Reagents; D012997:Solvents; D004024:Dicyclohexylcarbodiimide