Instrumentation for MALDI-MSI – Part I Ionization Sources and Design

Soltwisch, Jens

Abstract

Modern matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) offers a wide field of applications ranging from rapid fingerprinting of tissue sections to imaging of single cells with high spatial resolution. Naturally, the design of a MALDI ion source greatly varies with the intended application as well as the type of mass spectrometer it is connected to. This is reflected in the design of the translation stage, laser optics as well as ion optical elements. This chapter introduces the general concept of different MALDI-MSI ion sources and compares and discusses their advantages and drawbacks. Next to different pressure regimes, it will present design considerations with regard to laser delivery and spatial resolution and introduce the most important means of post-ionization employed in MALDI-MSI.