Table 3 Quantitative analysis of the lignin fractions by integration of 2D HSQC NMR spectra (results expressed per 100 Ar)
Samples | S/G | β-O-4 (A) | β-O-4 (A′) | β–β | β-5 | α-O-4/β-O-4 | PB (%) |
|---|---|---|---|---|---|---|---|
Cottonwood | 1.56 | 1.0 | 14.0 | 6.9 | 3.3 | ND | 6.3 |
Black willow | 2.69 | 3.0 | 10.3 | 7.8 | 1.8 | ND | 2.0 |
Aspen | 2.35 | 0.8 | 9.5 | 4.9 | 1.4 | 3.6 | 8.8 |
Eucalyptus | 4.91 | 0.8 | 12.2 | 10.1 | 1.5 | ND | ND |
Loblolly pine | ND | 2.8 | 9.2 | 2.9 | 8.5 | ND | ND |