Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School of Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
Tobacco Science Research Center, Japan Tobacco Inc., 6-2 Umegaoka, Aoba-ku, Yokohama, Kanagawa, 227-8512, Japan.
Sci Rep. 2020 Oct 2;10(1):16426. doi: 10.1038/s41598-020-73464-8.
The purpose of the present study was to visualize the sorption dynamics of small compounds, such as propylene glycol (PG) in cellulose acetate (CA) film, by deuterium (d) labeling-aided confocal Raman spectroscopy (CRM). Substitution of hydrogen atoms in the target molecule with deuterium caused a marked shift of C-H bond-related Raman bands to low wavenumbers, while the number of deuterium did not affect the magnitude of the shift. Raman bands derived from the stretching vibration of C-H near 2900 cm for PG and ethanol were shifted to approximately 2100 cm for PG-d6 and ethanol-d5 in the silent region of the CA Raman spectrum. When PG-d6 was dissolved in glycerol triacetate (GTA), the observed Raman intensity ratio at 2123 cm of PG-d6 against 1739 cm of GTA (C=O bond-related) showed a linear relationship between the molar and intensity ratios, indicating that the observed Raman intensity can be used for quantitative assay of the target in polymer film. The depth profiling experiments by CRM revealed that the distribution (or sorption) of PG-d6 in CA film was successfully visualized as a function of Raman band at the characteristic 2123 cm intensity ratio.
本研究的目的是通过氘（d）标记辅助共聚焦拉曼光谱（CRM）可视化小化合物（如丙二醇（PG）在醋酸纤维素（CA）膜中的吸附动力学。目标分子中氢原子被氘取代会导致 C-H 键相关拉曼带向低波数明显移动，而氘的数量不影响移动的幅度。PG 和乙醇的 C-H 伸缩振动在 2900cm 附近产生的拉曼带在 CA 拉曼光谱的静默区中分别向 PG-d6 和乙醇-d5 的约 2100cm 移动。当 PG-d6 溶解在甘油三乙酸酯（GTA）中时，在 2123cm 处观察到的 PG-d6 对 1739cm 处 GTA（C=O 键相关）的 Raman 强度比的观察到的 Raman 强度比呈现出摩尔和强度比之间的线性关系，表明观察到的 Raman 强度可用于聚合物膜中目标物的定量分析。CRM 的深度剖析实验表明，成功地将 CA 膜中 PG-d6 的分布（或吸附）可视化作为特征 2123cm 强度比的拉曼带的函数。
