Advanced Mass Calibration and Visualization for FT-ICR Mass Spectrometry Imaging

TL;DR

This paper presents advanced calibration techniques and a novel visualization method for FT-ICR mass spectrometry imaging, achieving sub-ppm accuracy and high-resolution spectral visualization of biological tissue sections.

Contribution

It introduces a new calibration strategy for high mass accuracy and a Mosaic Data-cube visualization approach for FT-ICR MS imaging data.

Findings

Sub-ppm mass accuracy over tissue sections

Ion abundance correction reduces error to 0.158 ppm

High-resolution visualization reveals spectral features

Abstract

Mass spectrometry imaging by Fourier transform ion cyclotron resonance yields hundreds of unique peaks, many of which cannot be resolved by lower performance mass spectrometers. The high mass accuracy and high mass resolving power allow confident identification of small molecules and lipids directly from biological tissue sections. Here, calibration strategies for Fourier transform ion cyclotron resonance mass spectrometry imaging were investigated. Sub parts-per-million mass accuracy is demonstrated over an entire tissue section. Ion abundance fluctuations are corrected for by addition of total and relative ion abundances for a root-mean-square error of 0.158 ppm on 16,764 peaks. A new approach for visualization of Fourier transform ion cyclotron resonance mass spectrometry imaging data at high resolution is presented. The Mosaic Data-cube provides a flexible means to visualize the entire mass range at a mass spectral bin width of 0.001 Dalton. The high resolution Mosaic Data-cube resolves spectral features not visible at lower bin widths, while retaining the high mass accuracy from the calibration methods discussed.