High-throughput prediction of eucalypt lignin syringyl/guaiacyl content using multivariate analysis: a comparison between mid-infrared, near-infrared, and Raman spectroscopies for model development

Table 5 Raman vibrational modes identified from regression coefficient plots and spectral assignments corresponding to lignin and/or lignin monomers

Vibrational mode from regression coefficients plot	S/G/H vibrational mode and spectral assignment(s)
351-376	369 (S), 357, 370 (G) [35]
378-401	370-399 (S) [20]
474-623	529, 564, 582 (S), 541, 559, 590 (G) [35]
665-725	711 (S) [43]
665-725	712 (G), 701 (H) [35]
736-756	741 (S) [43]
736-756	741 (H) [35]
748-765	761 (G) [43]
765-796	781-820 (S) [20]
	784 (G) [43]
	793 (G) [35]
800-835	819-864 (H) [20]
	810 (S) [43]
	799 (S), 823 (H) [35]
875-939	920 (G) [43]
875-939	907 (S), 921 (G) [35]
991-1051	1024 (G) [43]
991-1051	1043 (S), 1036 (G) [35]
1091-1131	1108 (S), 1124 (G), 1094 (H) [43]
1091-1131	1116 (S), 1122 (G), 1105 (H) [35]
1135-1195	1154 (S), 1158 (G), 1168 (H), 1170 (Lignin) [28]
	1138–1160 (S), 1162–1188 (G), 1163–1179 (H) [20]
	1148 (S), 1186 (G), 1164 (H) [43]
	1152, 1187 (S), 1155, 1186 (G), 1173, 1199 (H) [35]
1205-1242	1200 (H) [28]
	1213–1218 (H) [20]
	1228 (S), 1215 (H) [43]
	1214, 1241 (S), 1208, 1241 (G), 1216 (H) [35]
1261-1346	1337 (S), 1263 (H), 1270 (Lignin) [28]
	1262–1275 (G), 1318–1332, 1331–1338 (S), 1286–1299 (H) [20]
	1331 (S), 1270–1285 (G), 1338 H [43]
	1331 (S), 1272, 1288 (G), 1298, 1331 (H) [35]
1434-1448	1454-1460 (S), 1452–1465 (G), 1452–1459 (H) [20]
1434-1448	1452 (S), 1455 (G), 1455 (H) [35]
1587-1606	1594 (S), 1589, 1604 (G), 1588, 1606 (H), 1591, 1604 (Lignin) [28]
	1588 (S) [43]
	1609 (S), 1609 (G), 1599 (H) [35]
1623-1629	1634 (S), 1633 (G), 1632 (H), 1634 (Lignin) [28]
1653-1672	coniferyl (G) and sinapyl (G) alcohol [44]

ISSN: 2731-3654