This work describes the development of a system that combines a derivatization protocol based on the Katritzky reaction with paper spray ionization mass spectrometry (PSI-MS) for the analysis of amino acid neurotransmitters in mouse brain tissues. The system is relatively simple, consisting of spraying the derivatization solution onto a mouse brain section mounted on a glass slide, applying a small volume of solvent to moisten the sample, pressing a triangular paper onto the sample surface to transfer the sample constituents to the paper surface, and using the paper as a substrate for PSI-MS analysis. The Katritzky reaction facilitated the ionization of the amino acids by reacting a pyrylium salt with the amino group of the analytes, forming very stable pyridinium cations, which greatly increased the sensitivity of the PSI-MS analysis. Most of the intensities of the amino acids modified by the Katritzky reaction were more than 10 times greater than the nonderivatized ones. The system was applied for the analysis of brain sections obtained from mice with Parkinson's disease, and the amino acids gamma-aminobutyric acid (GABA) and glycine (Gly), two compounds very well-known in studies of Parkinson's disease, were readily detected. The results suggest that the Katritzky reaction combined with PSI-MS might offer a significant advance in the knowledge on protocols that improve the sensitivity of detection of crucial biological compounds.

中文翻译：

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结合 Katritzky 反应和纸喷雾电离质谱法，增强对小鼠脑切片中氨基酸神经递质的检测。

这项工作描述了一种系统的开发，该系统将基于 Katritzky 反应的衍生化协议与纸喷雾电离质谱 (PSI-MS) 相结合，用于分析小鼠脑组织中的氨基酸神经递质。该系统相对简单，包括将衍生化溶液喷洒到安装在载玻片上的小鼠大脑切片上，使用少量溶剂润湿样品，将三角形纸压在样品表面以将样品成分转移到纸上表面，并使用纸作为 PSI-MS 分析的基板。Katritzky 反应通过使吡喃盐与分析物的氨基反应，形成非常稳定的吡啶鎓阳离子，从而促进了氨基酸的离子化，从而大大提高了 PSI-MS 分析的灵敏度。Katritzky 反应修饰的大多数氨基酸的强度比非衍生化的高 10 倍以上。该系统用于分析从患有帕金森病的小鼠获得的脑切片，并且很容易检测到氨基酸 γ-氨基丁酸 (GABA) 和甘氨酸 (Gly)，这两种化合物在帕金森病研究中非常知名。结果表明，Katritzky 反应与 PSI-MS 相结合可能会在提高关键生物化合物检测灵敏度的协议知识方面取得重大进展。并且很容易检测到氨基酸 γ-氨基丁酸 (GABA) 和甘氨酸 (Gly)，这两种化合物在帕金森病研究中非常有名。结果表明，Katritzky 反应与 PSI-MS 相结合可能会在提高关键生物化合物检测灵敏度的协议知识方面取得重大进展。并且很容易检测到氨基酸 γ-氨基丁酸 (GABA) 和甘氨酸 (Gly)，这两种化合物在帕金森病研究中非常有名。结果表明，Katritzky 反应与 PSI-MS 相结合可能会在提高关键生物化合物检测灵敏度的协议知识方面取得重大进展。