All pollen samples show peaks or shoulders in the range 1870-1520 cm -1 is the carbonyl area, and the double bond C=C , due to the bending vibrations of -OH from water, and stretching vibrations of functional groups ketones C=O of fructose, and aldehyde CH=O of glucose, is related to the stretching vibration of C=O functional group present in the acetic, gluconic acids and originating from the fermentation of sugar [see .