Structural analysis of poplar and Masson pine lignocresols and comparison of their bovine serum albumin adsorption characteristics

Abstract

In this study, poplar and Masson pine trees were used as raw materials to examine the structural characteristics of lignin that had been isolated with a phase separation system. Following phase separation, the structure of lignocresol (LC) was characterized with Fourier transform infrared (FTIR) spectroscopy, high-performance gel permeation chromatography (GPC), proton nuclear magnetic resonance (1H-NMR) spectroscopy, and two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance (2D HSQC NMR) spectroscopy. Phase separation made it possible to analyze the proportions and the differences between various structural units in the isolated lignin, as well as the types of linkages between them. In-situ and real-time monitoring of the adsorption and desorption properties of the LC membranes were conducted with a bovine serum albumin (BSA) assay and a quartz crystal microbalance (QCM-D). Our findings revealed that the LC membrane of Masson pine adsorbed more BSA than that of poplar, indicating Masson pine LC molecules were more hydrophobic due to a higher proportion of guaiacyl (G)-type lignin units.