Table 1. Lignin unit abundances (as per 100 C9 units) calculated from HSQC NMR analysis of crude and MW adjusted values from fractioned lignin analysis.
| Unit a | Spruce CEL | Indulin AT kraft lignin |
||
| Crude | MW adjusted d | MW adjusted + HSQC0 d | ||
| A | 38.5 | 7.0 | 9.8 | 10.3 |
| B | 13.0 | 1.6 | 2.8 | 2.6 |
| C | 3.0 | 1.6 | 2.1 | 1.8 |
| D | 2.4 | 0.2 | — | — |
| X | 5.8 | 1.8 | 1.7 | 1.6 |
| SR | 1.0 | 2.1 | 2.0 | 1.8 |
| DHCA | 5.2 | 4.7 | 4.6 | 4.1 |
| J | 3.7 | 0.0 | 0.0 | 0.0 |
| S | 2.9 | 0.0 | 0.0 | 0.0 |
| C′ | 0.0 | 0.5 | 0.6 | 0.6 |
| Z-EE | 0.0 | 1.1 | 1.0 | 1.0 |
| E-EE | 0.0 | 2.8 | 2.5 | 3.1 |
| SB1 | 0.0 | 2.7 | 1.5 | 1.9 |
| SB5 | 0.0 | 6.5 | 3.8 | — |
| AG | 1.4 | 2.2 b | 3.8 b | — |
| V | 1.4 | 0.8 | — | — |
| AV | 0.0 | 0.7 | — | — |
| VA | 2.0 | 0.4 | — | — |
| HA | 0.0 | 0.8 | — | — |
| Ar | 0.0 | 0.5 | — | — |
| Total c | 84.3 | 45.3 | 38.6 | 35.2 |
aSee Fig. 2 for structures.
bDetermined in acetylated lignin.
cSymmetrical units C, C′ and SB1 counted as 2 aromatic units each.
d AG, V, AV, HA, Ar units were not included in the fractionation analysis due to their low abundance making quantification challenging.