Abstract: A novel method for the analysis of chemical components in tobacco flavors was established using stir bar sorptive extraction (SBSE) and thermal desorption coupled with gas chromatography-mass spectrometry (GC-MS). The different parameters affecting the extraction of the analytes from the samples to the poly(dimethylsiloxane)(PDMS) coated stir bars and the conditions affected thermal desorption were investigated. The optimized extraction conditions were that the sample was extracted with a stir bar (10 mm length and 0.5 mm thickness) at 1100 r/min for 1 h at ambient temperature. Desorption was carried out from 20 ℃ ramped to 250 ℃ at 60 ℃/min and hold for 2 min under a helium flow of 50 mL/min in the splitless mode while maintained the cryofocusing temperature of -100 ℃ in a CIS-4 injector of the GC-MS system. Finally, the CIS-4 injector was raised to a temperature of 280 ℃ and the analytes were separated by GC and detected by MS using full scan mode (m/z 35-400). Under the described conditions, about 30 components were identified from the tobacco flavors, and the major components included esters, ketones, aldehydes, etc. The average relative standard deviation (RSD) of peak areas of 30 components for 6 determinations was less than 10%. The good repeatability made SBSE a powerful tool for the routine quality control analysis of chemical components in tobacco flavors.

Key words: gas chromatography (GC), mass spectrometry (MS), thermal desorption, tobacco flavors , stir bar sorptive extraction