Abstract:

A method was developed for the determination of seven glucocorticoid residues in animal muscle using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample extraction was performed using ethyl acetate, followed by cleanup based on solid phase extraction (SPE). The chromatographic separation was achieved on a C18 column (150 mm×2.1mm, 3.5μm) with water/acetonitrile/formic acid system as the mobile phase in gradient elution mode. The MS condition used was negative electrospray ionization mode. Under these conditions, the linear range of the developed method was between 0.5 ng/mL and 5 ng/mL, with a linear correlation coefficient of no less than 0.9963, the detection limit was 1.0μg/kg for beclomethasone, 2.0 μg/kg for hydrocortisone, 0.5μg/kg for the others, and the average spike recoveries for the seven molecules were between 82.75% and 91.87%, with a relative standard deviation (RSD) of 4.43% or lower (n = 5).

Key words: glucocorticoid, solid phase extraction, liquid chromatography-tandem mass spectrometry