Determination of Menthol in Cut Tobacco and Cigarette Filters of Mentholated Cigarettes by GC-MS with Ultrasonic Extraction

Two chopped filters (or 1.000 g cut tobacco) were placed into a 100 mL conical bottle, and 40 mL of methanol and 80 μL of 50 g·L^-1 n-propyl benzoate solution for internal standard were added. After extraction for 30 min under 80% ultrasonic power, the supernatant was filtered with 0.45 μm filtration membrane, and menthol in the supernatant was determined by gas chromatography-mass spectrometry with HP-INNOWAX column (30 m×0.25 mm, 0.25 μm) as stationary phase. Electron bombardment ion source, full scanning mode and selective ion monitoring mode were adopted in mass spectrometry. Linear relationship between values of the ratio of menthol peak area to internal standard peak area and mass concentration of menthol was obtained in the range of 10.0-400 mg·L^-1, with detection limit (3s) of 0.17 mg·L^-1. Tests of intra and inter group precision for cut tobacco and cigarette filters were made, and values of RSDs (n=5) were all less than 5.0%. Test for recovery was made by standard addition method, giving results in the range of 94.0%-101%.