Table 4. Results of Phenolic Hydroxyl Group Determination in the Lignin Fractions as GAE in the Analytical Working Solution (Expressed in μg/mL) and as Total Phenolic Content in the Dry Lignin (Expressed in mmol/g)a.
| fraction | GAE (μg/mL) | phenolic −OH content (mmol/g) |
|---|---|---|
| LF-0 | 357 | 4.2 |
| LF-S | 333 | 3.9 |
| LF-R5 | 394 | 4.6 |
| LF-P5 | 367 | 4.3 |
| LF-R2 | 374 | 4.4 |
| LF-P2 | 422 | 5.0 |
a
Estimated standard errors (1 σ, from calibration data): GAE ±20 μg/mL and phenolic OH content ±0.2 mmol/g.