Table-1.

Fourier transform infrared spectroscopy described fingerprint bands of peppermint oil and microemulsion.

Microemulsion bands	Peppermint oil bands	Functional groups
-	3781.72	(–OH stretching)
3438	3424	(–OH stretching)
2923.56	2923.56	CH3 groups
2861.82	2857.99	CH2 groups
2102.99	-	Weak C C stretching alkyne group
1730	1748	C O bonding
1639.2	1630	N H stretching primary amines
1459.85	1458.29	C H bonding methylene group
1354.75	1374.04	Phenol and alcohol group
1295.93	-	Ester carbonyl group and phenol
1251.58	-	Phenyl and acryl C O
1098.26	1035	C–O–C bonding
945	-	O H bond carboxylic acids
913	-	O H bond carboxylic acids