Skip to main content

International Journal of Interdisciplinary Research

Table 2 Functional groups of purified blue pigment from FTIR Spectra

From: Extraction of Indigo dye from Couroupita guianensisand its application on cotton fabric

Wave number (cm−1)

Functional group with mol. motion

Std. synthetic indigo

Purified blue pigment

3020-3000

Aromatics C-H Stretch

3018.39

3020.32

3400-2400

Carboxylic acids O-H Stretch

2399.28

2399.00

1640-1500

Amines N-H bend

1618.17

1519.80

1430-1290

C-H in-plane bend

1425.00

1425.30

1320-1210

Carboxylic acids (C-O stretch)

1215.07

1215.07

860-680 (s)

Aromatic C-H bending

754.12

757.97

730-550

C-Cl stretch, acid chloride

669.25

669.25