Abstract: Objective To establish a simple high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS)
system for determination of capsaicin in rat plasma. Methods Rat plasma (100 μl) was extracted with mixed solvent (ethyl
acetate∶acetone 85∶15) after addition of 50 ng/ml internal standard, and analyzed by Agilent 6460 Triple Quadrupole LC/MS
system. The detection was performed with multiple reactions monitoring using electrospray ionization. The precursor/product
ion transitions were monitored at m/z 306→137 (+Ion mode) for capsaicin. Verapamil was used as the internal standard at m/
z455→165. Results The analysis time was only 1.5 min in the positive mode; the calibration curve was linear in the
concentration range of 1.85-370 ng/ml. The lowest limit of quantification reached 1.85 ng/ml. The extraction recoveries were
77.34%, 70.64% and 78.02% for the three quality control concentration levels (3.7, 37, and 370 ng/ml), respectively. Conclusion
The LC-MS/MS system is simple, accurate, reliable and time-saving for determination of trace amount of capsaicin in plasma.