13C CP/MAS NMR光谱法分析烟草果胶的含量和结构

摘要

A method utilizing13C CP / MAS NMR spectra was developed for quantitative determination and structure analysis of pectin in tobacco. NMR spectra was employed to measure pectin after the extraction of tobacco samples with acid under optimized condition and was applied to calculate galacturonic acid content (GalA), degree of methylation (DM) and acetylation (DA) by peak fitting in C-6 region. Results were in good agreement with convenient methods (chromography and gravimetric method) and NMR method could realize quantitative and structure analysis of pectin in tobacco simultaneously.%采用CP/MAS 13C NMR光谱法分析烟草果胶的含量和结构。对烟草果胶进行了优化提取后，再对其13C NMR光谱图C-6吸收峰区域进行了详细研究，用于计算果胶中半乳糖醛酸（GalA）、甲酯度（DM）和乙酰度（DA）的含量，并就建立的定量方法与经典的色谱法和重量法进行了比较。结果表明，CP/MAS13C NMR光谱法测定烟草样品中果胶的含量是可靠的，化学位移和峰面积可用来计算烟草果胶分子的组成、甲酯度和乙酰度，同步实现烟草中果胶的含量和结构分析。