Use of ATR-FTIR Spectroscopy and Chemometrics for the Variation of Active Components in Different Harvesting Periods of Lonicera japonica

Table 2

Infrared spectrum band assignments.

Wavenumber (cm^−1)	Vibration	Suggested biomolecular assignment	Reference
4000–3500	O-H stretching	H2O	[14]
3800–2600	-OH stretching	Water molecules	[19]
3615	νs(OH) free	Water molecules	[19]
3490	νas(OH), HB	Water molecules	[19]
3420, 3400	νs(OH), HB	Water molecules	[19]
3400	O-H bond vibration	Sugar compound	[20]
3400	Free N-H stretching	Amide	[19]
3392	O-H stretching		[21]
3307	-OH deformation mode		[22]
∼3300	ν(NH), HB	Amide A, proteins	[19]
3286–3284	N-H stretching	Amide A of proteins	[23]
3286–3284	O-H stretching	Polysaccharides	[23]
3286	N-H stretching	Amide	[24]
3280	νs(OH), HB	Water molecules	[19]
3280	H-O-H stretching		[25]
∼3100	ν(NH), HB	Amide B, proteins	[19]
3077	νCH	Alkane/alkene	[24]
3030–2800		Lipids	[23]
3020–3010	ν(=CH)	Unsaturated fatty acids, cholesterol esters	[19]
3008	Olefinic HC=CH	Unsaturated lipids	[23]
3000–2800	-CH3 and -CH2 groups	Phospholipids and fatty acids	[19]
2960–2955	νas(CH3)	Protein side chains, phospholipids, ceramides, fatty acids	[19]
2960	CH3- stretching (asym)	Alkane/alkene	[24]
2957	Asymmetric CH3 stretching		[25]
2956	CH3 antisymmetric stretching	Lipids, protein side chains	[23]
2924–2915	νas(CH2)	Mainly lipids: phospholipids, ceramides, and fatty acids	[19]
2923, 2853	CH2- stretching		[21]
2923	CH2 antisymmetric stretching	Lipids (mainly)	[23]
2920	Asymmetric CH2 stretching		[25]
2900	C-H bonds	Sugar compounds	[20]
2875–2872	νs(CH3)	Protein side chains, phospholipids, ceramides, fatty acids	[19]
2872	CH3- stretching (sym)	Alkane/alkene	[24]
2872	CH3 symmetric stretching	Proteins (mainly), lipids, carbohydrates, nucleic acids	[23]
2855–2847	νs(CH2)	Mainly lipids: phospholipids, ceramides, fatty acids	[19]
2854	CH2 symmetric stretching	Lipids (mainly)	[26]
2844	CH2- stretching		[22]
2700–2330	NH^+ stretching and overtones or combination bands in Fermi resonance	Tertiary amine hydrochloride salts	[9]
2500–2000		Unsaturated hydrocarbons	[27]
2442–2208	O-C-O stretching	CO2	[14]
2400–2250		CO2	[26]
2360, 2340		CO2	[26]
1900	The 2nd overtone of the CO bond	Caffeoylquinic acids	[28]
1800–1650		Chlorogenic acid	[29]
1800–900	Fingerprint region	All molecules	[23]
1742	Carbonyl C=O stretching	Cholesterol esters	[23]
1740		Triglycerides	[30]
1740–1720	ν(C=O)	Phospholipids, esters, glycerides	[19]
1734, 1627, 1522, 1440, 1410, 1367, 1315, 1255		Chlorogenic acid, flavonoids	[22]
1734	C=O stretching	Polyphenol	[22]
1720	The asymmetric overtone of the C-H bond	Caffeoylquinic acids	[28]
1700–1400		Fatty acids, lipids, proteins	[30]
1690–1610	ν(C=O)	Amide I (∼70–80% C=O stretch)	[19]
1682, 1639, 1471, 1284, 1181, 1111, 1032, 982, 950, 822, 789		Organic acids, flavonoids	[22]
1682	C=O stretching	Chlorogenic acid	[22]
1650	C=O stretching	Amide I (proteins, lipids, and carbohydrates)	[24]
1650	The first C-H overtone		[31]
1644		Triterpenoid saponin	[32]
1641	C=O stretching ß-sheet structure	Amide I (protein)	[23]
1636	C=C vibrations (aromatic ring skeletal)		[22]
1635		The crystalline water of sugar compounds	[20]
1627, 1522	C=C vibrations (aromatic ring skeletal)		[22]
1600–1450		Secologanic acid, chlorogenic acid, galuteolin	[33]
1590		Amino acids	[30]
1560–1500	δ(NH), ν(CN)	Amide II (∼40–60% N-H in-plane bend, ∼20–40% C-N stretch)	[19]
1545, 1455, 1450, 1410, 880, 875		Carbonate	[26]
1538	N-H bend, C-N stretch a helical structure	Amide II (protein)	[23]
1516		Tyrosine	[30]
1491	C=C aromatic ring stretching vibrations		[9]
1473–1468	δ(CH2), δas(CH3)	Proteins, lipids	[19]
1462	δ(CH2), δas(CH3)	Proteins, lipids	[19]
1454–1451	CH2 bending	Lipids	[23]
1454	δ(CH2), δas(CH3)	Proteins, lipids	[19]
1453	CH2 scissoring		[25]
1440, 1410, 1376	OH vibrational modes	Organic acid	[22]
1428, 1407	NCH3 bending		[9]
1420–1300	The second overtone of the carbonyl group	Secologanic acid, chlorogenic acid, galuteolin	[33]
1413	C-H deformation vibration (CH3 and -CH2- groups)		[28]
1412	O-C=O symmetric stretching	Glycine	[25]
1400	ν(C=O) + δs(CH3)	COO-: proteins, lipids, fatty acids	[19]
1398	CH3 bending	Proteins	[14]
1398	COO- stretching (sym)	Fatty acids, amino acids	[14]
1397	COO- symmetric stretching	Fatty acids	[23]
1394	C=O stretch of COO-		[25]
1393, 1358	νCO/νCOO-, δCHx (x = 1, 2, 3), δNH vibrational modes	Proteins and lipids	[24]
1350	The second overtone of stretching O-H and C-H bonds		[31]
1343	δ(CH2)	C-H wagging	[19]
1333	C-H2 wagging	Glycine	[25]
1315, 1250	C-O stretching		[22]
1243, 1240	ν(CN), δ(NH) + νas()	Amide III (∼40% C-N stretch, 30% N-H in-plane bend, 20% methyl-C stretch)	[19]
1242	Asymmetric stretch		[25]
1241	νas(）	Nucleic acids, phospholipids	[30]
1234	antisymmetric stretching	Nucleic acids (mainly), phospholipids	[23]
1200–1000	C-O stretching	Polysaccharides, glycosides	[21]
1200–1000		Nucleic acids, hydrocarbons, phosphates	[24]
1200–900	ν(CC), δ(COH)	Carbohydrates	[19]
1190–976, 962, 660–520, 472		Phosphate ions	[26]
1171	Ester C-O asymmetric stretch		[25]
1170–1100	The second overtone of C-H (-CH2)	Secologanic acid, chlorogenic acid, galuteolin	[33]
1167	C-H stretching (CH3 and -CH2- groups)		[28]
1166	CO-O-C antisymmetric stretching	Ester bonds in cholesteryl esters, ribose ring formations: RNA	[23]
1155	C-O stretching	Oligosaccharides, triacylglycerols	[14]
1152, 1080, 1022	δ(CHO), ν(C-O)	Glycogen, glucose	[24]
1150–850		Phosphate group	[26]
1150, 1020	-OH deformation modes		[22]
1141, 1079	C-O glycosidic bonds		[20]
1124	ν(C-O)	RNA	[30]
1120	C-O bonds	Ribose	[30]
1118	ν(C-O)	RNA, carbohydrates	[30]
1117	N-H3 rocking	Glycine	[25]
1091	p-Substituted aromatic vibrations		[9]
1090–1075	νs()	Phospholipids	[19]
1080	C-O stretch		[25]
1074	symmetric stretching	Nucleic acids, phospholipids, glycogen, polysaccharides, glycolipids	[23]
1051	C-O stretching	Starch	[14]
1039	C-N stretching	Glycine	[25]
1034		Glycolytic components and nucleic acids	[24]
1010 (1225–950)	Aromatic C-H in-plane bending		[9]
996		Nucleotides	[19]
971	C-N^+-C stretching	RNA	[23]
950–400		H2O	[24]
919	Ribose ring vibrations	RNA/DNA	[23]
914–600	O-C-O bending	CO2	[14]^1
914	CH2 rocking	Glycine	[25]
894	The ß-configuration and α-configuration		[20]
877, 744		C-H deformation in proteins	[19]
833, 822	Aromatic C-H out-of-plane bending		[9]
771	C-O-C symmetry vibration	D-Glucopyranosyl ring	[20]
730–718	ρ(CH2)	Lipids	[19]