Quantitative analysis of human serum corticosterone by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry

An original method based upon high-performance liquid chromatography coupled to electrospray ionization mass spectrometry has been developed for corticosterone (B) quantification in human serum. After extraction by diethyl ether using triamcinolone (T) as an internal standard, solutes are separated on a C-18 microbore column (250x1.0 mm, I.D.), using acetonitrile-water-formic acid (40:59.9:01, v/v/v) as the mobile phase (flow-rate 40 mu l/min). Detection is performed on an API 1 single quadrupole mass spectrometer equipped with a ESI interface and operated in positive ionization mode. Corticosterone quantifications were realized by computing peak area ratios (B/T) of the serum extracts analyzed in SLM mode (m/z 347 and m/z 395 for B and T, respectively), and comparing them with the calibration curve (r=0.998). (C) 1999 Elsevier Science B.V. All rights reserved.