Fourier transform Raman assignment of guaiacyl and syringyl marker bands for lignin determination

Miyuki Takayama, Toru Johjima, Takeshi Yamanaka, Hiroyuki Wariishi, Hiroo Tanaka

研究成果: ジャーナルへの寄稿学術誌査読

47 被引用数 (Scopus)

抄録

A near infrared fourier transform Raman (NIR-FTR) spectroscopic technique was utilized to characterize lignin in wood. The Raman bands for C=C stretching derived from 4-hydroxy-3-methoxyphenyl (guaiacyl) nuclei and from 3,5-dimethoxy-4-hydroxyphenyl (syringyl) nuclei exist independently. The NIR-FTR analysis of a series of lignin model compounds indicated that a syringyl band was shifted to a lower frequency compared to a guaiacyl band. This shift was also observed in chemically synthesized lignin (DHP). Syringyl DHP, in which all the aromatic nuclei consist of syringyl type, exhibited a C=C stretching band at 1594 cm-1, while guaiacyl DHP exhibited the band at 1599 cm-1. These bands were designated as syringyl and guaiacyl marker bands, respectively. Chemical and physical treatment of hardwood and softwood exhibited different characteristics. One of the reasons is the chemical structure of lignin. Softwood mainly contains only guaiacyl lignin, while hardwood contains both guaiacyl and syringyl lignin, and the syringyl/guaiacyl (S/G) ratio varies among species. Under high-resolution conditions (1 cm-1), the NIR-FTR spectra of 10 hardwoods (wood meal samples) revealed that both syringyl and guaiacyl marker bands existed. On the other hand, the spectra of softwoods contained only a guaiacyl marker bands existed. On the other hand, the spectra of softwoods contained only a guaiacyl marker band. The S/G ratio in hardwood calculated from the peak area intensity ratio of two marker bands shows a linear relationship with the S/G ratio obtained from conventional nitrobenzene oxidation analysis with the correlation factor > 0.96. Furthermore, if peak component separation analysis was combined, low-resolution spectral data gave a similar S/G ratio. Either syringyl of guaiacyl marker bands can be assigned in the NIR-FTR spectra of wood blocks (saw-cut surface). This spectral technique may provide an easy-handling and non-destructive analytical method for lignin determination.

本文言語英語
ページ(範囲)1621-1628
ページ数8
ジャーナルSpectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
53
10
DOI
出版ステータス出版済み - 1月 1 1997

!!!All Science Journal Classification (ASJC) codes

  • 分析化学
  • 原子分子物理学および光学
  • 器械工学
  • 分光学

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