We describe the construction and application of a new MALDI source for FT-ICR mass spectrometry imaging. The source includes a translational X-Y positioning stage with a 10 × 10 cm range of motion for analysis of large sample areas, a quadrupole for mass selection, and an external octopole ion trap with electrodes for the application of an axial potential gradient for controlled ion ejection. An off-line LC MALDI MS/MS run demonstrates the utility of the new source for data- and position-dependent experiments. A FT-ICR MS imaging experiment of a coronal rat brain section yields ∼200 unique peaks from m/z 400–1100 with corresponding mass-selected images. Mass spectra from every pixel are internally calibrated with respect to polymer calibrants collected from an adjacent slide.

J. Am. Soc. Mass Spectrom.

Smith, D.F, Aizikov, K, Duursma, M.C, Giskes, F.G, Spaanderman, D.-J, McDonnell, L.A, … Heeren, R.M.A. (2011). An external matrix-assisted laser desorption ionization source for flexible FT-ICR mass spectrometry imaging with internal calibration on adjacent samples. J. Am. Soc. Mass Spectrom., 22(1), 130–137. doi:10.1007/s13361-010-0003-x