Macromolecules and Interfaces Institute, Virginia Tech, Blacksburg, Virginia 24061, United States.
Biomacromolecules. 2012 Apr 9;13(4):1043-50. doi: 10.1021/bm201770q. Epub 2012 Mar 6.
This study presents the first application of (2)H NMR spectroscopy to quantify lignocellulose matrix orientation, and it demonstrates the ability to separately investigate oriented and unoriented amorphous domains in intact natural plant tissue. Matrix orientation is evaluated using NMR quadrupolar interactions in small deuterated probe molecules absorbed into bulk Liriodendron tulipifera sapwood. Ethylene glycol-d(4) deuterium spectra reveal two distinct amorphous domains, a highly oriented phase in the secondary wall S2 layer and an isotropic domain probably reflecting the compound middle lamella (CML). The oriented and isotropic signal areas exhibit thermally reversible changes, postulated to reflect probe redistribution between the S2 layer and the CML. Preliminary studies on a more powerful wood swelling agent, N,N-dimethylformamide-d(1), are also discussed. This (2)H NMR technique provides a new avenue for analysis and understanding of lignocellulose ultrastructure and promises to create new insights in correlating biomass processing with morphological change.
本研究首次应用 (2)H NMR 光谱定量木质纤维素基质取向，并证明了在完整的天然植物组织中分别研究取向和无定形区域的能力。通过吸收到边材中的小氘代探针分子的 NMR 四极相互作用来评估基质取向。乙二醇-d(4)氘谱揭示了两个不同的无定形域，次生壁 S2 层中的高度取向相和可能反映复合中层（CML）的各向同性域。取向和各向同性信号区域表现出热可逆变化，推测反映了探针在 S2 层和 CML 之间的重新分布。还讨论了对更强大的木材膨胀剂 N,N-二甲基甲酰胺-d(1)的初步研究。这种 (2)H NMR 技术为木质纤维素超微结构的分析和理解提供了新的途径，并有望在将生物质加工与形态变化相关联方面产生新的见解。
