Table I.
The Raman bands used for analysis and their assignment to lignin (L) and/or carbohydrate components (cellulose [C], glucomannan [GlcMan], and xylan [Xyl]) according to the literature (Wiley and Atalla, 1987; Agarwal and Ralph, 1997; Edwards et al., 1997; Agarwal, 1999; Saariaho et al., 2003)
| Wavenumber | Component | Assignment |
|---|---|---|
| cm−1 | ||
| 2,945 | L, GlcMan, and C | CH str. in OCH3 asym. |
| 2,897 | C | CH and CH2 str. |
| 1,660 | L | Ring conjugated C=C str. of coniferyl alcohol; C=O str. of coniferaldehyde |
| 1,620 | L | Ring conjugated C=C str. of coniferaldehyde |
| 1,601 | L | Aryl ring str., sym. |
| 1,508 | L | Aryl ring str., asym. |
| 1,462 | L and C | HCH and HOC bending |
| 1,423 | L | O–CH3 deformation; CH2 scissoring; guaiacyl ring vibration |
| 1,376 | C | HCC, HCO, and HOC bending |
| 1,333 | C | HCC and HCO bending |
| 1,274 | L | Aryl–O of aryl OH and aryl O–CH3; guaiacyl ring (with C=O group) mode |
| 1,150 | C | Heavy atom (CC and CO) str. plus HCC and HCO bending |
| 1,143 | L ? | |
| 1,122 | C, Xyl, and GlcMan | Heavy atom (CC and CO) str. |
| 1,096 | C, Xyl, and GlcMan | Heavy atom (CC and CO) str. |
| 1,045 | L ? | CO of aryl–O–CH3 and aryl–OH at 1,033 ? |
| 997 | C | |
| 903 | C | Heavy atom (CC and CO) str. |