Zhang Yan-Xia, Zhang Yi-Da, Shi Yan-Ping
CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences (CAS), Lanzhou 730000, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences (CAS), Lanzhou 730000, PR China.
Food Chem. 2023 Jan 1;398:133911. doi: 10.1016/j.foodchem.2022.133911. Epub 2022 Aug 10.
A superior sectioning sample preparation protocol is the basic guarantee for maintaining data reliability in MALDI-TOF-MSI analysis. Despite significant advances in sample preparation, visualization of lipids in hard and dry cereals remains difficult due to their inherent physicochemical properties. Thus, a cryosections preparation method was designed via poly-l-lysine soaking, conductive tape adhesion and embedding medium fixation, which preserved the spatial integrity of lipids in cereals without causing analyte delocalization and obvious background interference. Higher signal intensity and clearer imaging of lipids in rice, wheat and barley (Qingke) were obtained using the established sample preparation method. Moreover, the spatial distribution of lipids was visualized in rice with different storage years, which found that the phosphatidylinositols (PIs) and phosphatidylglycerols (PGs) could be used for evaluation of rice aging degree. Our study provided molecular level guidance for further discussion of rice aging mechanism, rice quality evaluation and safety monitoring.
一种优质的切片样品制备方案是在基质辅助激光解吸电离飞行时间质谱成像（MALDI-TOF-MSI）分析中维持数据可靠性的基本保障。尽管样品制备取得了显著进展，但由于硬粒和干谷物中脂质固有的物理化学性质，对其进行可视化分析仍然困难。因此，设计了一种通过聚-L-赖氨酸浸泡、导电胶带粘贴和包埋介质固定的冷冻切片制备方法，该方法保留了谷物中脂质的空间完整性，且不会导致分析物移位和明显的背景干扰。使用所建立的样品制备方法，在水稻、小麦和大麦（青稞）中获得了更高的脂质信号强度和更清晰的成像。此外，还对不同储存年份的水稻中脂质的空间分布进行了可视化，发现磷脂酰肌醇（PIs）和磷脂酰甘油（PGs）可用于评估水稻的老化程度。我们的研究为进一步探讨水稻老化机制、水稻品质评价和安全监测提供了分子水平的指导。
