OBJECTIVETo establish a simple high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS) system for determination of capsaicin in rat plasma.

METHODSRat 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.

RESULTSThe 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.

CONCLUSIONThe LC-MS/MS system is simple, accurate, reliable and time-saving for determination of trace amount of capsaicin in plasma.