Determination of Glucocorticoids in Muscle Tissues by Liquid Chromatography-Electrospray Tandem Mass Spectrometry

A method was developed to determine cortisone, cortisol, prednisone and dexamethasone in muscle tissues by high performance liquid chromatography. tandem mass spectrometry (LC-ESI-MS/MS). Deconjugation of glucocorticoids was carried out by enzymatic hydrolysis. These preliminary steps were followed by ethyl acetate extraction and HLB solid phase extraction clean up step for all matrices. Chromatographic separation was achieved on C-8 column and MS/MS data were obtained in the multiple reaction monitoring mode using negative electrospray ionization. Calibration graphs were prepared in the 0. 5-50. 0 mu g/L range and good linearity was achieved (R-2 >= 0. 99). The limits of detection (LOQ) and the limits of quantification (LOD) were 0. 13-0. 25 mu g/kg and 0. 25-0. 50 mu g/kg, respectively. Spiking at the levels of 0. 5, 5. 0 and 10. 0 mu g/L, the average recovery for glucocorticoids ranged from 74. 0% to 101. 8%. The relative standard deviations (RSD) were between 0. 7%-8. 6%.