MALDI imaging and analysis of fossils

现代质谱学与软电离技术相结合，是表征分子和超分子化合物的有力工具。它不仅提供了分子的质量，而且还可以提供关于它们的结构以及生物聚合物的序列和修饰的信息。目前，在生命科学、化学、制药、法医学等领域有许多成熟的质谱学方法和测量方案，以极高灵敏度针对从蛋白质和多肽、脂类、糖、有机分子、金属络合物到合成聚合物的各种分子。因此，使用现代质谱学来检测化石样本中的有机残留物是非常有诱惑力的。然而，许多已建立的程序源于生命科学，不能直接应用于矿化样品。粉状样品的脱矿和提取是克服障碍并实现质谱分析的可行方法，但这是以丢失分析物空间分布信息为代价的。另一方面，已建立的空间分辨方法，如二次离子质谱仪，通常不会采样完整的分子，而是非特定的碎片。因此，该项目的目的是与2685(石化)研究单位密切合作，开发新的方法，通过基质辅助激光解吸/电离(MALDI)质谱仪对化石样品中完整的有机分子进行空间分辨检测。预期工作计划的主要部分包括优化实验改变的鸵鸟骨和强烈矿化的恐龙化石骨的样品制备程序。一旦找到了对这些样品进行MALDI成像的可靠和可靠的方法，将用空间分辨率测量胶原及其可能的残留物。将开发进一步的方法来对琥珀昆虫进行MALDI成像，并检测化石中保存下来的彩色色素。

Modern mass spectrometry in combination with soft ionization techniques is a powerful tool for the characterization of molecular and supramolecular compounds. It not only provides the mass of the molecules, but it can also yield information on their structure and on the sequence and modifications of biopolymers. Currently, there are many well-established mass spectrometric methods and measuring protocols for applications in life sciences, chemistry, pharmacy, forensics etc. that target a broad variety of molecules ranging from proteins and peptides, lipids, sugars, organic molecules, metal complexes to synthetic polymers with extreme sensitivity. It is thus very tempting to use modern mass spectrometry to detect organic remains in fossil samples. Many of the established procedures, however, stem from life sciences and cannot directly be applied to mineralized samples. Demineralization and extraction of powdered samples is a viable way to overcome the obstacle and enable mass spectrometric analysis, but it comes at the high cost of losing information about the spatial distribution of the analytes. On the other hand, established spatially-resolved methods like secondary-ion mass spectrometry often do not sample intact molecules, but rather unspecific fragments. The intention of this project thus is to develop new methods for the spatially-resolved detection of intact organic molecules in fossil samples via matrix-assisted laser desorption/ionization (MALDI) mass spectrometry in close collaboration within the research unit FOR 2685 (fossilization). A major part of the intended work program consists of optimizing sample preparation procedures of experimentally altered ostrich bone as well as of strongly mineralized fossil dinosaur bone. Once a reliable and robust method for MALDI imaging of these samples has been found, collagen and putative remainders thereof will me measured with spatial resolution. Further methods will be developed for MALDI imaging of amber insects and for the detection of preserved color pigments in fossils.