Determination of menthone and pulegone in Schizonepeta tenuifolia and Schizonepeta oil by GC

OBJECTIVE To establish a method for determination of menthone and pulegone in Schizonepeta tenuifolia and Schizonepetaoil.METHODS The contents of menthone and pulegone were determined by GC with PEG-20M fused capillary column(30 m×0.53 mm,1 μm) and FID detector,nitrogen as the carrier gas.Both injector and detector temperatures were set at 250℃,and the column temperature was 140℃.The method was employed with naphthalene as the internal standard.RESULTS The linear ranges were 0.2-2.5 mg·ml-1(r=0.9999) for menthone and 0.2-2.5 mg·ml-1(r=0.9992) for pulegone,the mean recoveries(n=9) of menthone and pulygone were 99.0% and 99.6%,respectively.CONCLUSION The method is simple and accurate,which can be applied to the determination of menthone and pulegone in Schizonepeta Tenuifolia and Schizonepetaeoil.