Analysis of volatile and semi-volatile compounds in tobacco using off-line combination of liquid chromatography and capillary gas chromatography-mass spectrometry

A method of off-line combination of liquid chromatography and capillary gas chromatography-mass spectrometry (LC-CGC/MS) was established for the analysis of volatile and semi-volatile compounds in tobacco. The separation mechanism of volatile and semi-volatile compounds was studied. An LC column of 250 mm x 2.0 mm packed with 5 microm amino-bonded silica was used as stationary phase for the separation. n-Hexane/dichloromethane/acetonitrile (90: 6.6: 3.4, v/v/v) was used as mobile phase. Five fractions from one LC run were collected in five nitrogen-blowing flasks, separately. The same fractions from 10 LC runs were combined together and concentrated to 1 mL by nitrogen blowing, and then were analyzed by CGC/MS. The column of DB-5MS (60 m x 0.25 mm x 0.25 microm) was used for CGC/MS analysis. Comparing with direct CGC/MS analysis of the same sample, the LC-CGC/MS system is suitable for a complex sample, and has a higher reliability of qualitative analysis.