Fig. 4: Dimer mass change and increment change for most common interunit linkages through acetylation.

1a, β-5’ (381 m/z)’. 2a, β-β’ (381 m/z). 3a, β-O-4’ (399 m/z). 4a, α-O-4’. 5a, 4-O-5’. 6a, 5-5’. 7a, DBDO. 1b, acetylated β-5’ (507 m/z)’. 2b, acetylated β-β’ (465 m/z). 3b, acetylated β-O-4’ (567 m/z). 4b, acetylated α-O-4’. 5b, acetylated 4-O-5’. 6b, acetylated 5-5’. 7b, acetylated DBDO. *Suggestion for α-o-4’ (or α-O-γ’ as alternative) being an observed 442 m/z increment in acetylated sample. **5-5’ is suggested by literature to occur as a dimerization reaction, and not as an addition of one single monomer to a growing chain. This increment is not included in the analysis, but the overall contribution of a theoretical monomeric unit to the observed 5-5’ m/z is showcased to illustrate the mass contribution this unit has in an oligomer. A brief illustration of the acetylation mechanism employed for discernment is given at the bottom of the figure.