Table 3 The FT-IR functional groups of purified TK

3402.43

N-H stretching

3201.83

O-H stretching

3016.67

Alkene C-H stretching

2862.36

Aliphatic C-H stretching

1666.50, 1612.49, 1589.34

C=O stretching, C=C stretching and N-H bending

1441.89

O-H bending and C-N stretching (superimposed bands)

1095.57

C-O stretching

617.22

Alkene C-H bending