Table 3.

μ-RS, SERS, and FT-IR spectroscopy peak position and assignments for GCF samples References [24,25,26,27,39].

Assignment Mode	Peak Position SERS (cm−1)				Peak Position Raman (cm−1)				Peak Position FT-IR (cm−1)
	0	2	7	14	0	2	7	14	0	2	7	14
S–S bond stretching	465
Phenylalanine	621
Tyrosine	825
Deoxyribose bending CO2H of tyrosine	895								897
PO43−	946
PO43− ν1 symmetric stretching, apatite					984	985	986	986
C–H bending phenylalanine	1007				1002
C–O stretching of carbohydrates									1039	1038	1035	1039
symmetric PO2− stretching of nucleic acids									1087	1087	1067	1092
Nucleic acid base PO2−						1100	1100
C–O asymmetric stretching and COH bending of lipids									1160	1158	1158	1158
Cytochrome						1167	1167	1167
Nucleic acid C–N	1176				1176
Amide III	1242	1242	1242
PO2− asymmetric stretching of nucleic acids									1253	1255	1254	1253
Amide III, CH2 deformation	1276				1280
CH2/CH3 twisted									1311	1314	1313	1308
Adenine/guanine of nucleic acids	1348	1348	1348		1345	1345	1345
symmetric bending of CH3 of nucleic acids									1376	1361	1388	1384
Cytochrome			1390
COO– stretching of aminoacids									1424	1419	1415	1423
CH3 symmetric stretching CH2 lipids/proteins scissoring										1462	1459
CH2	1470
Carotene						1540	1540
Amide II (N–H bending of proteins)									1547	1539	1545	1548
Amide II/cytochrome	1577				1575	1577	1577	1577
C=C stretching of amino acids									1598	1594	1598	1596
Amide I (β-sheet)					1625	1625	1611
Amide I (α-helix)	1641				1640	1640
C=O stretching of proteins (Amide I band)									1656	1650	1655	1655
CH3 symmetric stretching of lipids									2873	2880	2877	2881
CH2 asymmetric stretching of lipids									2927	2930	2929	2916
CH3 asymmetric stretching of lipids									2974	2981	2984	2937
NH stretching of Amide A OH stretching									3356	3357	3359	3365