3.3 IR analysis of the obtained oil
The obtained P. Nagi kernel oil was also carried out the FT-IR analysis. The FT-IR spectra displayed in figure 1 . It appeared a weak =C-H stretching band at 3008cm-1, because the oil contains the unsaturated fatty acids and flavonoids, which contain the =C-H groups; the strong stretching bands at 2854-2953cm-1 were confirmed as C-H, for there are many saturated C-H bonds in the molecules in this oil; the strong stretching band at 1747cm-1 was confirmed as -C=O and -COOH, for the oil contains different kinds of unsaturated fatty acids and saturated fatty acids(which contain COOH group) together with flavonoids(which contain C=O group);the medium stretching band at 1463cm-1 was attributed to the absorbance of C=C; the medium stretching bands at 1099-1236cm-1 were attributed to the bending vibration of C-H and the medium stretching bands at 723cm-1 was the characteristic peak of benzene (which was attributed to the flavonoids). The peak signals of FT-IR are consistent well with the functional groups of compounds listed in table 4 .