Department of Chemistry and Biochemistry, University of the Sciences, Philadelphia, Pennsylvania 19104, United States.
Anal Chem. 2010 Nov 15;82(22):9164-8. doi: 10.1021/ac102339y. Epub 2010 Oct 25.
Laserspray ionization (LSI) is a new approach to producing multiply charged ions from solids on surfaces by laser ablation of matrixes commonly used in matrix-assisted laser desorption/ionization (MALDI). We show that the only necessity of the laser for producing multiply charged ions is to deliver particles or droplets of the matrix/analyte mixture to an ionization zone which is simply a heated inlet to the vacuum of the mass spectrometer. Several other methods for delivering sample are demonstrated to produce nearly equivalent results. One example shows the use of an air gun replacing the laser and producing mass spectra of proteins by shooting pellets into a metal plate which has matrix/analyte applied to the opposite side and near the ion entrance inlet to the mass spectrometer. Multiply charged ions of proteins are produced in the absence of any electric field or laser and with only the need of a heated ion entrance capillary or skimmer. The commonality of the matrix with MALDI and the mild conditions necessary for formation of ions brings into question the mechanism of formation of multiply charged ions and the importance of matrix structure in this process.
激光喷雾电离（LSI）是一种新的方法，通过通常用于基质辅助激光解吸/电离（MALDI）的基质的激光烧蚀，从表面上的固体中产生多电荷离子。我们表明，产生多电荷离子的激光的唯一必要条件是将基质/分析物混合物的颗粒或液滴输送到离子化区，该离子化区仅仅是质谱仪真空的加热入口。展示了几种其他的用于输送样品的方法，这些方法可以产生几乎相同的结果。一个例子显示了使用空气枪代替激光，并通过将颗粒射向金属板来产生蛋白质的质谱，其中基质/分析物施加到金属板的相对侧，并且靠近质谱仪的离子入口入口。在没有任何电场或激光的情况下，并且仅需要加热的离子入口毛细管或文丘里管，就可以产生蛋白质的多电荷离子。基质与 MALDI 的通用性以及形成离子所需的温和条件，使得多电荷离子形成的机制以及基质结构在该过程中的重要性受到质疑。
