Rapid method for the determination of stanozolol in meat with supercritical fluid extraction and liquid chromatography-mass spectrometry

Stanozolol is isolated from animal tissues, such as bovine meat by automated supercritical fluid extraction (SFE). After the addition of the internal standard stanozolol-d3 and sample pretreatment, the analytes are extracted from the matrix by supercritical CO2 and trapped directly in-line on aminopropyl placed in the extraction vessel. The samples are analysed by liquid chromatography combined with single quad mass selective detection liquid chromatography-mass spectrometry (LC-MS) for screening and quantification and ion-trap mass selective detection (LC-MSn) for confirmation of the identity. For quantification, the deuterated internal standard is added and the protonated molecule of the analyte and internal standard are monitored. For confirmation of the identity of the analyte, two transition ions (two MS/MS ions) are monitored and the ratios between the ions are calculated and compared with those of standards. The detection limit of the screening method is 0.2 mug kg(-1), the limit of identification is 0.5 mug kg(-1). The mean within-laboratory reproducibility ranges from 11-18% (%R.S.D.) at the concentration level of 0.5-5 mug kg(-1) (n = 18). Running the SFE procedure overnight allows the analysis of 24 samples of meat per day. (C) 2002 Elsevier Science B.V. All rights reserved.