Sample Prep
Homogenize the defatted tissue sample in a homogenizer. Weigh 4.00±0.05 g of the homogenized sample into a 15 mL centrifuge tube, add 4 mL of Reagent A, vortex for 2 min, then add 1 mL of Reagent B, vortex for 2 min. Add 5 mL of extraction solvent, close the centrifuge tube cap, vortex to mix for 1 min, centrifuge at 4000 r/min for 5 min. Transfer 3 mL of the upper organic phase into a 10 mL centrifuge tube, then add 50 μL of protectant, vortex for 5–6 s to mix thoroughly, and evaporate to near dryness under a nitrogen stream at 40–50°C. Add 300 μL of sample diluent, vortex for 30 s to obtain the test solution. [Note: 1. The drug is volatile; when approximately 50 μL of liquid remains at the bottom of the centrifuge tube during nitrogen evaporation, remove immediately. The laboratory reference time for nitrogen evaporation is 5 min. 2. If emulsification occurs, break the emulsion and perform a second centrifugation.]