Characterization of 25 tropical hardwoods with Fourier transform infrared, ultraviolet resonance Raman, and 13C-NMR cross-polarization/magic-angle spinning spectroscopy
Characterization of 25 tropical hardwoods with Fourier transform infrared, ultraviolet resonance Raman, and 13C-NMR cross-polarization/magic-angle spinning spectroscopy
复制标题
DOI：
10.1002/app.24143
复制
发表时间：
2006-10-05
影响因子：
3
通讯作者：
Stewart, Derek
中科院分区：
文献类型：
--
作者：
Nuopponen, Mari H.;Wikberg, Hanne I.;Stewart, Derek
采用傅里叶变换红外光谱（FTIR）、紫外共振拉曼光谱（UVRR）和C-13-NMR交叉偏振/魔角旋转光谱法对25种来自加纳的热带硬木进行了检测。FTIR和UVRR光谱数据进行了主成分分析，而四个选定的样品表现出大的结构和组成的变化进行了更详细的研究，通过NMR光谱。测定了样品中乙酰溴木质素和α-纤维素的含量以及丙酮可溶物的含量。FTIR光谱模型中最突出的主成分主要是由于木质素结构和碳水化合物含量以及羰基结构的数量和类型的变化而分离样品，而UVRR光谱数据区分了各种芳香族和其他不饱和结构。缩合木质素/单宁型结构的存在下，检测到从UVRR和FTIR加载线图的次要主成分。缩合单宁也观察到在偶极移相NMR谱。此外，NMR结果表明，结晶纤维素和半纤维素的量和木质素中的愈创木基/愈创木基比例的变化。NMR和FTIR数据表明，在大多数情况下，愈创木基单元的量越高，乙酰溴木质素的水平越高，样品的生物抗性越好。(c)2006年Wiley期刊，
Twenty-five tropical hardwoods from Ghana were examined with Fourier transform infrared (FTIR), ultraviolet resonance Raman (UVRR), and C-13-NMR cross-polarization/magic-angle spinning spectroscopy. FTIR and UVRR spectral data were subjected to principal component analysis, whereas four selected samples exhibiting large structural and compositional variation were investigated in more detail by NMR spectroscopy. The acetyl bromide lignin and alpha-cellulose contents of the samples and the amount of acetone-soluble substances were also determined. The most prominent principal components of the FTIR spectral model separated samples mainly due to the variations in lignin structures and carbohydrate contents and the amount and type of carbonyl structures, whereas UVRR spectral data distinguished between various aromatic and other unsaturated structures. The presence of condensed lignin/tannin-type structures were detected from UVRR and FTIR loading line plots of the minor principal components. Condensed tannins were also observed in the dipolar dephasing NMR spectra. Furthermore, the NMR results showed variations in the amount of crystalline cellulose and hemicelluloses and in the syringyl/guaiacyl proportions in lignin. Both NMR and FTIR data suggest that in most cases, a higher amount of guaiacyl units correlated with higher levels of acetyl bromide lignin and better bioresistance of the samples. (c) 2006 Wiley Periodicals,