Coal samples composed of vitrinite, liptinite, and inertinite are characterized by KBr-FTIR spectroscopy. It exhibits the highest aromaticity (ratio of CHar at 3,000-3,100 cm(-1) or 700-900 cm(-1) versus CHal at 2,800-3,000 cm(-1)), reflecting the lowest hydrocarbon generating potential in the first froth fraction compared to all the other fractions. The ratio of CHal/(CHal +C=C) (i.e. A factor), which reflects the hydrocarbon-generating potential, is the lowest for the first concentrate. Variations of semiquantitative ratios differ less significantly between 15 s and 90 s. However, large difference of aromaticity is found between feed coal and the first concentrate. The DOC value is slightly higher for the first concentrate than the feed fractions.