Wavelength dependence of UV-MALDI mass spectrometry and of direct UV-LDI-MS without matrix

在MALDI质谱分析中，分析灵敏度受激发激光波长的影响很大。在本研究项目的第一个资助期内，利用一组选定的基质体系和多肽作为分析物，首次在280-377 nm波长范围内系统地研究了UV-MALDI的解吸和电离机制。这些结果表明，通过调整激光波长以适应矩阵的各个吸收峰，可以大大提高分析性能。第二个供资期将在几个重要方面以这些成果为基础。既定的MALDI矩阵和使用它们的分析物类别将全面地描述改进的潜力。优化的基质波长系统提供改进的分析灵敏度，将应用于空间分辨组织成像质谱（MALDI-MSI）。接下来的标准基质，液体基质系统，允许产生高电荷的肽离子将被表征。将波长范围扩展到213-450 nm，进一步探索了新的分析可能性，例如，通过无基质紫外- ldi - ms分析小分子和紫外- ldi - msi分析组织中的代谢物。这些研究也将加深我们对MALDI基本机制的认识。

In MALDI mass spectrometry, analytical sensitivity is largely influenced by the wavelength of the excitation laser. In the 1st funding period of the research project, the UV-MALDI desorption and ionization mechanisms were for the first time investigated systematically in the wavelength range of 280-377 nm by utilizing a selected set of matrix systems and peptides as analytes. These results showed that analytical performance can be substantially enhanced by adjusting the laser wavelength to the individual peak absorption of matrices. The 2nd funding period will build on these results in several important aspects. Established MALDI matrices and the analyte classes for which they are utilized will be comprehensively characterized with respect to the potential for improvement. Optimized matrix-wavelength systems that offer improved analytical sensitivity will be applied to spatially-resolved tissue imaging MS (MALDI-MSI). Next to standard matrices, liquid matrix systems that allow the generation of highly charged peptide ions will be characterized. Extension of the wavelength range to 213-450 nm furthermore allows to explore novel analytical possibilities, among which are, for example, the analysis of small molecules by matrix-free UV-LDI-MS and the UV-LDI-MSI analysis of metabolites in tissue. The studies will also deepen our knowledge about the basic MALDI mechanisms.