Identification of cigarettes with different grades by using FTIR microspectroscopy.

In this paper, FTIR microspectroscopy was used to identify the cigarettes of three different grades such as Jinwan cigarettes (J group), Yinxiangyipin cigarettes (Y group) and Hongsanhuan cigarettes (H group). IR spectra and peak-area ratios (A /A, A /A, A/A and A/A) revealed significant differences among H, Y and J groups, reflecting the changes in chemical compositions with increased grade. Discriminant analysis was carried out on basis of the above peak-area ratios, achieving 100% accuracy for identification of H, Y and J groups. Principal component analysis (PCA) showed that carbohydrates and proteins were closely related to the quality of the cigarettes. In addition, curve fitting further confirmed that the structure of carbohydrates underwent changes due to the quality of the cigarettes. The above results suggest that FTIR microspectroscopy can identify different grades of the cigarettes, which may be helpful for tobacco research.