CIEPQPF, Department of Chemical Engineering, University of Coimbra, 3030-790 Coimbra, Portugal.
Carbohydr Res. 2010 Jul 2;345(10):1442-51. doi: 10.1016/j.carres.2010.02.016. Epub 2010 Feb 23.
UV-Resonance Raman (UV-RR) coupled with UV-visible Diffuse Reflectance (UV-vis DR) spectroscopy was applied to a solid-state study of chromophores in Eucalyptus globulus kraft cellulosic pulps bleached by chlorine dioxide and hydrogen peroxide. The UV-RR spectra were acquired at 325nm laser beam excitation, which was shown to be appropriate for selective analysis of chromophore structures in polysaccharides. The proposed approach allowed the monitoring of chromophores in pulps and to track the extent of polysaccharide oxidation. However, precaution was suggested while performing a quantitative analysis of chromophores at the characteristic band of approximately 1600cm(-1) because of charge transfer complexes (CTCs) that exist in the pulp. These CTCs can affect the intensity of the aforementioned band by diminishing the conjugate state in the chromophore moieties. The amount of carbonyl and carboxyl groups in polysaccharides correlated with the intensity of the band at 1093cm(-1). The analysis of UV-RR spectra revealed xylan as an important source of chromophores in eucalypt kraft pulp.
UV-Resonance Raman（UV-RR）与 UV-可见漫反射（UV-vis DR）光谱学相结合，应用于用二氧化氯和过氧化氢漂白的桉树硫酸盐纤维素浆中发色团的固态研究。在 325nm 激光束激发下获得了 UV-RR 光谱，这对于多糖发色团结构的选择性分析是合适的。该方法允许监测纸浆中的发色团并跟踪多糖氧化的程度。然而，由于在纸浆中存在电荷转移配合物（CTC），在大约 1600cm(-1) 的特征带处对发色团进行定量分析时，建议采取预防措施。这些 CTC 可以通过减少发色团部分中的共轭态来影响上述带的强度。多糖中的羰基和羧基基团的数量与 1093cm(-1) 处的带强度相关。UV-RR 光谱分析表明木聚糖是桉树硫酸盐浆中发色团的重要来源。
