Identification of ten corticosteroids in human hair by liquid chromatography-ionspray mass spectrometry.

摘要

This paper describes a screening procedure based upon high-performance liquid chromatography-ionspray mass spectrometry for the identification of ten corticosteroids in human hair: triamcinolone, prednisolone, prednisone, methylprednisolone, cortisone, cortisol, beta- and dexamethasone, flumethasone and beclomethasone. Hair strands were washed in methylene chloride, pulverized in a ball mill and 50 mg of the powdered hair were incubated in 1 ml Soerensen buffer, pH 7.6 for 16 h at 40 degrees C, in presence of 50 ng cortisol-d3 used as internal standard. Purification of the incubation medium was achieved on SPE C18 Isolute extraction columns. The eluates were evaporated to dryness and resuspended in 30 microliters MeOH before analysis by HPLC-IS-MS in positive and negative modes of detection. The validation parameters were found satisfactory for a corticosteroid screening procedure. The correlation coefficient of the calibration curve ranged from 0.939 to 0.997, showing linearity between 0.1 and 10 ng/mg, excepted for beclomethasone which was between 0.2 and 10 ng/mg. Extraction recovery at 4 ng/mg ranged from 43.2 to 85.7%. Repeatability (CV values) at 4 ng/mg ranged from 6.1 to 17.5%. The limits of detection ranged from 0.03 to 0.17 ng/mg for a signal-to-noise ratio of 2. The detection of prednisone and beclomethasone in three hair specimens obtained from forensic and clinical cases have documented corticosteroids incorporation into human hair.