Electronic Supplementary Information (ESI):

Table 1. Observations during sample preparation.

Method / Measured cellulose (mg)
to 1 ml TFA / Observation / Later observation
Standard / 25.5 / Dissolved / Brownish solution
1 / 39.3 / Greyish colour, dissolved, cellulose fibres were visible, 200 μl extra TFA was added to the sample measured in the NMR tube and it needed heating / Dark brown solution
1a / 31.2 / Dissolved / Brown gel
1a/2 / 30.9 / Greyish colour, dissolved / Brownish gel
2 / 51.5 / Dissolved / Brownish gel
3 / 32.2 / Dissolved / White gel
4 / 47.6 / Dissolved / Brownish gel + solution
4a / 36.1 / Greyish colour, dissolved / Brownish solution
5 / 32.6 / Yellowish colour, dissolved, cellulose precipitated at the end of the measurement / Brownish gel
5/2 / 33.6 / Greyish-yellowish colour, dissolved / Light coloured solution

Table 2. Observations during the preparation of lignin and hemicellulose samples.

Method / Measured in / Observation / Later observation
3
(Hemicellulose) / 500 μl sample (liquid) + 150 μl D2O / Dissolved / Brownish solution
4a
(Lignin) / 197.6 mg settled phase + 100.7 mg liquid phase + 1 ml TFA + 1 ml H2O / Yellow, dissolved / Transparent solution
4a
(Hemicellulose 1) / 297.3 mg hemicellulose (brown, liquid) + 700 μl 3.2 M NaOH +~ 0.5 g TFA / Dark yellow, dissolved / Transparent solution, white settled phase in bottom
4a
(Hemicellulose 2) / 436.5 mg hemicellulose (white, solid) + 600 μl 3.2 M NaOH + ~0.5 g TFA / Colourless, dissolved / Opalescent solution


Figure 1. 13C NMR spectra of certain fractions from method 4a.

The chemical shifts of the two singlets (19.33 and 176.14 ppm) in the spectrum of the supposed lignin-containing sample can be attributed to the chemical shifts of the methyl and carboxyl groups of acetic acid (20.8 and 178.12 ppm, SDBSWeb), therefore, it can be concluded that a certain amount of residual CH3COOH remained after the concentrated acetic acid treatment.


Figure 2. 13C NMR spectra of certain fractions from method 3.

Note that there are no H atoms bound to the C atom of the CO group, therefore, it should not produce a signal on the basis of the DEPT-135 pulse sequence; the appearance is due to pulse imperfections. In the 13C NMR spectrum of the cellulose fraction from method 3 (Figure 2), the characteristic peaks of TFA also become visible, although only at low intensities, due to pulse imperfections. It does not disturb the analysis; moreover, it is useful for chemical shift calibration.