*2.8. High-Performance Size-Exclusion Chromatography (HPSEC)*

The average molecular weight (Mw), the number average (Mn) and the polydispersity index (Mw/Mn) of MWL and the PFL were analyzed by HPSEC. The chromatography equipment employed was a Jasco LC Net II/ADC (Analog data Can) equipped with a refractive index detector provided with two Varian Polymer Laboratories PolarGel-M columns in series (300 mm × 7.5 mm). Isolated lignins were dissolved in the mobile phase which consisted in 0.1% of lithium bromide in dimethylformamide. The chromatographic conditions were as follows: injection volume 20 µL, a flow of 0.7 mL/min and a temperature of 40 ◦C. The calibration of the SEC was carried out using polystyrene standards with different molecular weights (between 62,500 and 266 g/mol) provided by Sigma Aldrich.
