Structural Characterization of Lignin and Its Degradation Products with Spectroscopic Methods

Table 1

UV spectroscopic absorptions of typical structures in lignin [25, 30, 50, 53–56].

Absorption maxima/nm	Electronic transition style	Chromophores and structures
200	π-π	Conjugated bonds/aromatic ring
240	n-π	Free -OH
282	π-π	Conjugated bonds/aromatic ring
320	π-π	Aromatic ring conjugated bond with C = C
320	n-π	C = O groups conjugated to aromatic ring
325	n-π	Etherified ferulic acid