Near-Infrared Spectroscopic Monitoring of the Diffusion Process of Deuterium-Labeled Molecules in Wood. Part I: Softwood

Abstract

The diffusion process of several molecules (D2O, n-butanol (OD) and t-butanol (OD)) in softwood (Sitka spruce) was investigated by means of a deuterium exchange method and Fourier transform near-infrared (FT-NIR) polarization spectroscopy. The location of OH groups in different states of order of cellulose in wood was clarified by analyzing the FT-NIR transmission spectra ranging from 7200 to 6000 cm(-1). Four absorption bands were assigned to 2 x v(OH) absorptions of the amorphous regions, OH groups in semi-crystalline regions, and two types of intramolecular hydrogen-bonded OH groups in the crystalline regions, respectively. The saturation level of accessibility was very different for these absorption bands (i.e., 70-80, 60, and 40-50% for the amorphous, semi-crystalline, and crystalline regions, respectively). However, the saturation accessibilities for each absorption band varied little with molecular structure and geometry of the diffusants. The diffusion rate of D2O was much faster than that of n-butanol (OD) and t-butanol (OD) for all states of orders. The size effect of the butanols led to slight differences in the diffusive transport in the crystalline regions.

Quantitative Prediction of Agarotetrol in Chinese Eaglewood Using Near Infrared Spectroscopy

“…The second-derivative spectra of the untreated wood (solid line) displayed peaks in some regions with stronger intensities. However, the spectra of the ethanol-extracted samples (dotted line) showed less absorption, such as for the bands at 5976 cm -1 and 4686 cm -1 , which were determined to be closely related to the aromatic ring in the lignin and extractives (Michell et al 1996;Tsuchikawa and Siesler 2003;Workman and Weyer 2007;Sandak et al 2011). Overall, these combined results confirmed that the CE extractives were changed by the extraction pretreatment.…”

“…Band 1 located at 5976 cm -1 was assigned to the Car-H 1 st stretching vibration of aromatic groups in the lignin (aromatic skeletal, or aromatic C-H in lignin) (Workman and Weyer 2007;Tsuchikawa and Siesler 2003;Sandak et al 2011). Band 2 located at 5936 cm -1 was assigned to the Car-H 1 st stretching vibration of the aromatic ring associated with aromatic skeletal structures in the lignin (Tsuchikawa and Siesler 2003;Workman and Weyer 2007;Sandak et al 2011). Band 3 located at 5848 cm -1 was assigned to the C-H 1 st stretching vibration of furanose/pyranose in the hemicellulose (Yonenobu and Tsuchikawa 2003).…”

Identification of Pinus species related to historic architecture in Korea using NIR chemometric approaches

“…In these absorption bands, all bands except for 5220 cm -1 assigned to water [18], are associated with cellulose among the wood components. The absorption bands at 7000, 5464 and 4280, and 4890-4620 cm -1 are assigned to amorphous regions in cellulose, semi-or crystalline regions in cellulose, and cellulose, respectively [8,18,19]. The absorption band of 4404 cm -1 is assigned to cellulose and hemicellulose, and 5980 cm -1 is the aromatic skeletal area due to lignin [18,20].…”

“…Brunner et al [6] reported that cluster analysis could be used to distinguish 12 different wood species. Tsuchikawa et al [7] developed a species classification method using NIR spectroscopy combined with Mahalanobis's generalized distance, and investigated the diffusion process of deuterium-labeled molecules using NIR spectroscopy [8]. The most widely used multivariate analysis techniques for species classification are principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA).…”

Predicting Rank of Japanese Green Teas by Derivative Profiles of Spectra Obtained from Fourier Transform Near-Infrared Reflectance Spectroscopy

“…As shown in Eq. (8), a second order weight factor (1/n) 2 contributes to the second derivative, which leads to the fact that several papers have utilized the first and second derivative for feature description of NIR spectra [1,17,[36][37][38][39][40][41][42][43]. In general, the 1 st derivative is explained by a simple measure of the slop of the spectral curve at every point, and 2 nd derivative is a measure of the change in the slop of the curve.…”