Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, Jiangsu Key Laboratory of Biomedical Materials, College of Chemistry and Materials Science , Nanjing Normal University , Nanjing 210023 , China.
Department of Chemistry , University of British Columbia , Vancouver BC V6T 1Z1 , Canada.
Anal Chem. 2018 Mar 6;90(5):3628-3636. doi: 10.1021/acs.analchem.8b00242. Epub 2018 Feb 26.
Polysaccharide characterization posts the most difficult challenge to available analytical technologies compared to other types of biomolecules. Plant polysaccharides are reported to have numerous medicinal values, but their effect can be different based on the types of plants, and even regions of productions and conditions of cultivation. However, the molecular basis of the differences of these polysaccharides is largely unknown. In this study, direct analysis in real time mass spectrometry (DART-MS) was used to generate polysaccharide fingerprints. Large saccharides can break down into characteristic small fragments in the DART source via pyrolysis, and the products are then detected by high resolution MS. Temperature was shown to be a crucial parameter for the decomposition of large polysaccharide. The general behavior of carbohydrates in DART-MS was also studied through the investigation of a number of mono- and oligosaccharide standards. The chemical formula and putative ionic forms of the fragments were proposed based on accurate mass with less than 10 ppm mass errors. Multivariate data analysis shows the clear differentiation of different plant species. Intensities of marker ions compared among samples also showed obvious differences. The combination of DART-MS analysis and mechanochemical extraction method used in this work demonstrates a simple, fast, and high throughput analytical protocol for the efficient evaluation of molecular features in plant polysaccharides.
多糖的结构表征相较于其他生物分子，对现有的分析技术提出了最大的挑战。据报道，植物多糖具有多种药用价值，但由于植物种类的不同，甚至由于产地和种植条件的不同，其效果也会有所不同。然而，这些多糖差异的分子基础在很大程度上是未知的。在本研究中，直接实时分析质谱（DART-MS）被用于生成多糖指纹图谱。在 DART 源中，通过热解，大的多糖可以分解成特征性的小片段，然后通过高分辨 MS 进行检测。温度被证明是大的多糖分解的关键参数。通过对一些单糖和寡糖标准品的研究，还研究了碳水化合物在 DART-MS 中的一般行为。基于精确质量，提出了碎片的化学式和假定的离子形式，误差小于 10 ppm。多元数据分析显示出不同植物物种的明显分化。样品间标记离子的强度也表现出明显的差异。本工作中使用的 DART-MS 分析与机械化学提取方法的结合，展示了一种简单、快速、高通量的分析方案，可用于有效评估植物多糖中的分子特征。
