Department of Chemistry and The BioCentre, University of Reading, Reading, United Kingdom.
J Proteome Res. 2010 Apr 5;9(4):1931-40. doi: 10.1021/pr901089j.
Matrix-assisted laser desorption/ionization (MALDI) is a key ionization technique in mass spectrometry (MS) for the analysis of labile macromolecules. An important area of study and improvements in relation to MALDI and its application in high-sensitivity MS is that of matrix design and sample preparation. Recently, 4-chloro-alpha-cyanocinnamic acid (ClCCA) has been introduced as a new rationally designed matrix and reported to provide an improved analytical performance as demonstrated by an increase in sequence coverage of protein digests obtained by peptide mass mapping (PMM) (Jaskolla, T. W.; et al. Proc. Natl. Acad. Sci. U.S.A. 2008, 105, 12200-12205). This new matrix shows the potential to be a superior alternative to the commonly used and highly successful alpha-cyano-4-hydroxycinnamic acid (CHCA). We have taken this design one step further by developing and optimizing an ionic liquid matrix (ILM) and liquid support matrix (LSM) using ClCCA as the principle chromophore and MALDI matrix compound. These new liquid matrices possess greater sample homogeneity and a simpler morphology. The data obtained from our studies show improved sequence coverage for BSA digests compared to the traditional CHCA crystalline matrix and for the ClCCA-containing ILM a similar performance to the ClCCA crystalline matrix down to 1 fmol of BSA digest prepared in a single MALDI sample droplet with current sensitivity levels in the attomole range. The LSMs show a high tolerance to contamination such as ammonium bicarbonate, a commonly used buffering agent.
基质辅助激光解吸/电离（MALDI）是质谱（MS）中用于分析不稳定大分子的关键电离技术。与 MALDI 及其在高灵敏度 MS 中的应用相关的一个重要研究和改进领域是基质设计和样品制备。最近，4-氯-α-氰基肉桂酸（ClCCA）已被引入作为一种新的合理设计的基质，并据报道，通过肽质量映射（PMM）获得的蛋白质消化物的序列覆盖率提高，从而改善了分析性能（Jaskolla，TW；等人。美国国家科学院院刊。2008 年，105，12200-12205）。这种新的基质显示出成为常用且非常成功的α-氰基-4-羟基肉桂酸（CHCA）的优越替代品的潜力。我们通过开发和优化使用 ClCCA 作为主要发色团和 MALDI 基质化合物的离子液体基质（ILM）和液体支撑基质（LSM），将这种设计又向前推进了一步。这些新的液体基质具有更好的样品均一性和更简单的形态。与传统的 CHCA 结晶基质相比，我们的研究获得的 BSA 消化物的序列覆盖率得到了改善，与含 ClCCA 的 ILM 相比，在当前纳摩尔级的灵敏度水平下，仅用一滴 MALDI 样品制备 1 fmol 的 BSA 消化物，其性能相似。LSM 对污染具有很高的耐受性，例如常用的缓冲剂碳酸氢铵。
