Digital Imaging Mass Spectrometry

TL;DR

This paper introduces a novel digital imaging mass spectrometer that uses ion optical means and an ASIC Timepix detector for rapid, high-resolution imaging of molecules on surfaces, enabling faster and more straightforward analysis.

Contribution

It presents a new imaging mass spectrometer design that achieves true digital imaging with high speed, spatial resolution, and simplified image reconstruction.

Findings

Spatial resolving power of ~84 μm

Mass resolution of 45

Imaging speed up to 4 kHz or more

Abstract

Methods to visualize the two-dimensional distribution of molecules by mass spectrometric imaging evolve rapidly and yield novel applications in biology, medicine, and material surface sciences. Most mass spectrometric imagers acquire high mass resolution spectra spot-by-spot and thereby scan the object's surface. Thus, imaging is slow and image reconstruction remains cumbersome. Here we describe an imaging mass spectrometer that exploits the true imaging capabilities by ion optical means for the time of flight mass separation. The mass spectrometer is equipped with the ASIC Timepix chip as an array detector to acquire the position, mass, and intensity of ions that are imaged by MALDI directly from the target sample onto the detector. This imaging mass spectrometer has a spatial resolving power at the specimen of (84\pm35) \mu m with a mass resolution of 45 and locates atoms or organic compounds on a surface area up to ~2 cm2. Extended laser spots of ~5 mm2 on structured specimens allowed parallel imaging of selected masses. The digital imaging mass spectrometer proves high hit-multiplicity, straightforward image reconstruction and its potential for high-speed readout at 4 kHz or more. This device demonstrates a simple way of true image acquisition like a digital photographic camera. The technology may enable a fast analysis of biomolecular samples in near future.