Table 2 FTIR spectra and the peak positions of the major IR bands of γ-Fe₂O₃ nanoparticles only and γ-Fe₂O₃-amylase enzyme hybrid.

3200–3600 cm^-1

O–H stretching, strong, alcohol

^1,4,29

2500–3300 cm^-1

O–H stretching, carboxylic acid

²⁹

2500–3300 cm^-1

O–H stretching (carboxylic acid), N–H stretching (amine salt), C-H stretching (alkane)

^1,28

Symmetric stretching of –CH₂

^1,8,28

P–H group, atmospheric CO₂

^24,29

P–H group

²⁴

P–H group

²⁴

P–H group

²⁴

Alkyl, carboxyl and amino

²⁸

C = O group of carboxylic acid

^1,24,28

1650–1580 cm^-1

N–H bending (amine), C = C stretching (cyclic alkene)

⁴

ν asCOO − , δ-NH₂, C = C, NH³⁺

²⁸

–CH₂ rocking band

¹

COO − symmetric stretching

¹⁰

COO − symmetric stretching

¹⁰

1350–1300 cm^-1

S = O, Strong stretching (Sulfone)

⁸

C–O stretching (carboxylic acid)

¹

1124–1205 cm^-1

C = C bending, strong, alkene

²⁸

Si–O–Si asymmetric stretching

^8,28

1070–1030 cm^-1

S = O stretching, strong (sulfoxide)

⁸

Iron oxyhydroxide (γ-FeOOH)

²⁶

Silanol groups

⁸

885–895 cm^-1

C = C bending, strong, alkene

²⁸

790–840 cm^-1

C = C bending, medium, alkene

²⁸

–CH₂ rocking band

¹

500–800 cm^-1

Fe–O stretching, strong

²⁸

Fe–O bond vibration

^26,27,28

Fe–O stretching vibration

⁸

500–600 cm^-1

Fe–O stretching, strong

^4,28