Department of Chemistry, Dongguk University, Seoul 04620, Korea.
Department of Chemistry, Hankuk University of Foreign Studies, Yongin 17035, Korea.
Molecules. 2022 Nov 4;27(21):7582. doi: 10.3390/molecules27217582.
Nanospray desorption electrospray ionization (nano-DESI) is one of the ambient desorption ionization methods for mass spectrometry (MS), and it utilizes a steady-state liquid junction formed between two microcapillaries to directly extract analytes from sample surfaces with minimal sample damage. In this study, we employed nano-DESI MS to perform a metabolite fingerprinting analysis directly from a leaf surface. Moreover, we investigated whether changes in metabolite fingerprints with time can be related to metabolite distribution according to depth. From a raw leaf, the mass spectral fingerprints of key metabolites, including flavonoids and prenylated phloroglucinols, were successfully obtained using ethanol as a nano-DESI solvent, and the changes in their intensities were observed with time via full mass scan experiments. In addition, the differential extraction patterns of the obtained mass spectral fingerprints were clearly visualized over time through selected ion monitoring and pseudo-selected reaction monitoring experiments. To examine the correlation between the time-dependent changes in the metabolite fingerprints and depth-wise metabolite distribution, we performed a nano-DESI MS analysis against leaves whose surface layers were removed multiple times by forming polymeric gum Arabic films on their surfaces, followed by detaching. The preliminary results showed that the changes in the metabolite fingerprints according to the number of peelings showed a similar pattern with those obtained from the raw leaves over time.
纳米喷雾解吸电喷雾电离 (nano-DESI) 是用于质谱 (MS) 的一种环境解吸电离方法，它利用在两个微毛细管之间形成的稳态液体结直接从样品表面提取分析物，对样品的损伤最小。在这项研究中，我们使用 nano-DESI MS 直接从叶片表面进行代谢物指纹分析。此外，我们还研究了随着时间的推移，代谢物指纹的变化是否与根据深度的代谢物分布有关。从原始叶片中，使用乙醇作为 nano-DESI 溶剂成功获得了包括类黄酮和prenylated phloroglucinols 在内的关键代谢物的质谱指纹图谱，并通过全质量扫描实验观察到它们的强度随时间的变化。此外，通过选择离子监测和伪选择反应监测实验，随着时间的推移，可以清楚地观察到获得的质谱指纹图谱的差异提取模式。为了检查代谢物指纹随时间变化与深度代谢物分布之间的相关性，我们对表面多次形成聚合阿拉伯树胶膜并随后去除的叶片进行 nano-DESI MS 分析。初步结果表明，根据去皮次数的代谢物指纹变化与原始叶片随时间的变化模式相似。
