MATRIX ASSISTED LASER DESORPTION--FUNDAMENTAL STUDIES

基质辅助激光解吸（MALD）与飞行时间质量耦合 近年来，光谱学已经成为一种强大的资源， 生物医学研究员 应用于分析广泛的 生物分子的重要类别，包括蛋白质，肽， 单克隆抗体、寡核苷酸和糖肽， 糖蛋白尤其令人印象深刻。 基础研究 基质辅助激光解吸的基本机理是 需要更好地理解解吸过程 本身 预计这些研究将扩大 技术并在诸如分子质量 准确度、灵敏度和质量分辨率。 主要关注的是基质/分析物相互作用的性质。 为 肽和蛋白质，观察到显著的基质加合物种类。 这些物种形成的确切机制尚不清楚，但 包括简单的脱水和脱羧反应。 的净结果 是离子种类，其干扰a的准确测定。 样品分子量，特别是对于大质量分析物， proteins. 各种旨在阐明这些性质的研究 描述了基质加合物种类，其目的是减少或 消除了这些麻烦的反应，从而提高了 从这项技术中获得的数据。 确实，如果可以的话 完成后，很可能更复杂的生物分子 可以通过这种技术探测系统。 实例包括结合 各种小分子（如药物）到大分子的研究 蛋白质（超过30，000 Da），目前难以执行 用这种技术。 提出了一些改善MALD性能的方法 法 这些措施包括利用静电部门从一个 传统的双扇区质谱仪作为能量过滤器， 提高可用的质量分辨能力。 这将允许更多 详细研究了基质加合反应，并改进了 用于生物分子研究。 为了增加结构性 来自MALD实验的信息，表面诱导 解离研究被描述用于对以下物质进行MS/MS实验： MALD产生的质子化分子离子。

Matrix assisted laser desorption (MALD) coupled to time-of-flight mass spectrometry has emerged in recent years as a powerful resource for the biomedical researcher. Applications to the analysis of a wide range of important classes of biomolecules, including proteins, peptides, monoclonal antibodies, oligonucleotides and glycopeptides and glycoproteins have been particularly impressive. Basic studies of the fundamental mechanism involved in matrix assisted laser desorption are needed to gain an improved understanding of the desorption process itself. Such studies are expected to expand the applicability of the technique and provide improvements in such areas as molecular mass accuracy, sensitivity and mass resolution. A primary concern is the nature of the matrix/analyte interactions. For peptides and proteins, significant matrix adduct species are observed. The exact mechanism for formation of these species is not known, but involve simple dehydration and decarboxylation reactions. The net result are ion species which interfere with the accurate determination of a samples molecular weight, particularly for large mass analytes such as proteins. A variety of studies aimed at elucidating the nature of these matrix adduct species are described, with the goal of reducing or eliminating these troublesome reactions, thus improving the utility of the data available from this technique. Indeed, if this can be accomplished, it is probable that even more complicated biomolecular systems can be probed by this technique. Examples include binding studies of various small molecules (such as pharmaceuticals) to large proteins (more than 30,000 Da), which currently are difficult to perform with this technique. Instrumental methods are proposed to improve the performance of the MALD technique. These include utilizing an electrostatic sector from a conventional double sector mass spectrometer as an energy filter to improve the mass resolving power available. This will allow more detailed studies of the matrix adduct reactions as well as improving the utility for biomolecular studies. In order to increase the structural information available from the MALD experiment, surface induced dissociation studies are described for performing MS/MS experiments on the protonated molecular ions produced by MALD.