Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Food Chem. 2021 Feb 15;338:127984. doi: 10.1016/j.foodchem.2020.127984. Epub 2020 Sep 17.
Mass spectrometry imaging (MSI) is a powerful technique for investigating the biomolecular locations within tissues. However, the isomeric compounds are rarely distinguished due to inability of MSI to differentiate isomers in the probing area. Coupling tandem mass spectrometry with MSI can facilitate differentiating isomeric compounds. Here MALDI-TOF/TOF tandem mass spectrometry imaging approach was applied to probing the spatial distributions of isomeric disaccharides in plant tissues. First, MS/MS imaging analysis of disaccharide-matrix droplet spots demonstrated the feasibility of distinguishing isomeric species in tissues, by measuring the relative intensity of specific fragments. Then, tandem MS imaging of disaccharides in onion bulb tissues indicated that sucrose and other unknown non-sucrose disaccharides exhibit heterogeneous locations throughout the tissues. This method enables us to image disaccharide isomers differentially in biological tissues, and to discover new saccharide species in plant. This work also emphasizes the necessity of considering isobaric compounds when interpreting MSI results.
质谱成像（MSI）是一种强大的技术，可用于研究组织内的生物分子位置。然而，由于 MSI 无法区分探测区域中的异构体，因此很少区分异构体化合物。将串联质谱与 MSI 相结合，可以促进异构体化合物的区分。这里应用 MALDI-TOF/TOF 串联质谱成像方法来探测植物组织中异构体二糖的空间分布。首先，通过测量特定片段的相对强度，对二糖-基质液滴斑点的 MS/MS 成像分析证明了在组织中区分异构体物种的可行性。然后，对洋葱鳞茎组织中二糖的串联 MS 成像表明，蔗糖和其他未知的非蔗糖二糖在整个组织中呈现出不均匀的位置。该方法使我们能够在生物组织中对二糖异构体进行差异成像，并在植物中发现新的糖种类。这项工作还强调了在解释 MSI 结果时考虑等质量化合物的必要性。
