烟草科技2017，Vol.50Issue(4)：65-71,102,8.DOI:10.16135/j.issn1002-0861.2016.0402
不同烟草材料中水分赋存状态的低场核磁共振分析
Analysis of occurrence state of moisture in different tobacco materials by low-field nuclear magnetic resonance
摘要
Abstract
In order to find out the occurrence state of moisture in tobacco materials, the inversion spectra of spin-spin relaxation time (T2) of cut strips, cut stems, cut reconstituted tobacco were analyzed by low-field nuclear magnetic resonance (LF-NMR). The effects of moisture content and microstructure of the tobacco materials on the relaxation time and peak area of relaxation signal of water molecules in T2 inversion spectra were investigated as well. The results showed that: 1) Within the moisture content range of 10%-35%, there typically existed 2-4 proton signal peaks in T2 inversion spectra of tobacco materials, of which the T21 peak having the relaxation time of 0.01-10 ms reflected the relaxation signal intensity of hydrogen proton of moisture. 2)With the increase of moisture content in tobacco materials, the relaxation time of peaks T21 for cut strips, cut stems and cut reconstituted tobacco gradually increased from 0.183 to 1.430, from 0.166 to 1.560 and from 0.166 to 1.650 ms, respectively. It reflected that the augmentation of the proportion of active migration moisture. 3) A significant linear correlation existed between the T21 relaxation peak area and the moisture content in tobacco material, it suggested that the T2 inversion signal could be used in the quantitative analysis of moisture content in tobacco materials. 4)Once the pores larger than 30 μm in natural tobacco material were damaged, the relaxation time of moisture reduced significantly, it indicated that the occurrence state of moisture in natural tobacco material was obviously affected by its microporous structure.关键词
低场核磁共振/烟草/水分/赋存状态/多孔结构Key words
Low-field nuclear magnetic resonance/Tobacco/Moisture/Occurrence state/Porous structure分类
轻工纺织引用本文复制引用
韩李锋,陈良元,李旭,马骥,崔凯,朱文魁..不同烟草材料中水分赋存状态的低场核磁共振分析[J].烟草科技,2017,50(4):65-71,102,8.基金项目
国家自然科学基金项目"植物多孔介质快速干燥过程中微细结构变化的分形特征及对热质传递影响机制"(51306213). （51306213）
