title: IR-MALDESI mass spectrometry imaging of biological tissue sections using ice as a matrix.
abstract: Infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging of biological tissue sections using a layer of deposited ice as an energy-absorbing matrix was investigated. Dynamics of plume ablation were first explored using a nanosecond exposure shadowgraphy system designed to simultaneously collect pictures of the plume with a camera and collect the Fourier transform ion cyclotron resonance FT-ICR mass spectrum corresponding to that same ablation event. Ablation of fresh tissue analyzed with and without using ice as a matrix were compared using this technique. Effect of spot-to-spot distance, number of laser shots per pixel, and tissue condition (matrix) on ion abundance were also investigated for 50 μm-thick tissue sections. Finally, the statistical method called design of experiments was used to compare source parameters and determine the optimal conditions for IR-MALDESI of tissue sections using deposited ice as a matrix. With a better understanding of the fundamentals of ablation dynamics and a systematic approach to explore the experimental space, it was possible to improve ion abundance by nearly one order of magnitude.
authors.affiliation: W.M. Keck Fourier Transform Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, NC, 27695, USA.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Robichaud
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Barry
authors.forename: David C
authors.initials: DC
authors.lastname: Muddiman
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology; D001923:Brain Chemistry; D016591:Histocytological Preparation Techniques / Q000379:methods*; D007053:Ice; D051379:Mice; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D007053:Ice