Functional groups Wave number (cm-1)
C=C (Aromatic) 1600-1400 cm-1
C=O (ester) 1750-1730 cm-1
C=O (carboxylic acid) 1725-1700 cm-1
C-O (ester/carboxylic acid) 1300-1000 cm-1
O-H (carboxylic acids) 3300-2500 cm-1
Table 10: IR values for the prominent peaks in the finger print region