Abstract: A gas chromatography-mass spectrometry (GC-MS) technique was used to establish a method for the determination of β2-stimulants in animal tissues. Animal tissues were homogenized with 1% perchloric acid solution, extracted with ethyl acetate: isopropanol (6: 4), purified by solid phase extraction column, derivatized with BSTFA + 1% TMCS, and then determined by GC-MS. The lowest detectable concentrations in the samples were terbutaline 0.5 μg / kg, clenbuterol 110 μg / kg and salbutamol 0.2 μg / kg.
1. Chromatographic conditions
Chromatography column: HP-5MS 5% phenylmethyl polysiloxane elastic quartz capillary column (30m × 0.25mm × 0.25 μm); inlet temperature: 300 ℃; column temperature program: initial temperature 150 ℃, hold for 3 min , Then raised to 240 ° C at 10 ° C / min for 1 min, then raised to 280 ° C at 20 ° C / min for 3 min; carrier gas: high purity helium (99.999%), flow rate 110 ml / min, not Split injection.
2. Mass spectrometry conditions
EI source, source temperature 230 ℃; electron energy 70 eV; interface temperature 280 ℃, electron multiplier voltage 1388V, mass spectrometer scanning range 50 ～ 550 amu; solvent delay: 8 min.
3. Sample processing
Weigh 5.0 g of the minced sample, add 30 ml of 1% perchloric acid solution, homogenize in a high-speed tissue homogenizer for 1 min, then sonicate at 80 ° C for 15 min, and centrifuge at 5000 r / min for 10 min. The supernatant was transferred to a separatory funnel, adjusted to alkaline with 50% sodium hydroxide, added with 30 ml of organic solvent and extracted with shaking, centrifuged, the organic phase was transferred into a triangular flask with a stopper, and the extraction was repeated once. Rotate to dryness at 50 ° C with anhydrous sodium sulfate. First dissolve with 3 ml of acetonitrile and 3 ml of n-hexane and transfer into a test tube. Mix and separate the n-hexane phase. After the acetonitrile phase is evaporated to dryness, dissolve to 3 ml with 3% ethanol / ethyl acetate. Take the Cle-SLX column and rinse with 5ml 3% ethanol / ethyl acetate first, then add 1 ml sample extract, add 5 ml 5% methanol / ethyl acetate to elute the collected component 1, then use 10 ml 50% The methanol / ethyl acetate eluent was collected to fraction 2, and the eluent was blown dry with nitrogen, respectively. Add 100 μl BSTFA + 1% TMCS, derivatize at 60 ° C for 30 min, dry with nitrogen, add 200 μl toluene to dissolve and centrifuge, take 110 μl for GC / MS analysis.
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