This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Recent advances in imaging mass spectrometry present need for improving techniques in terms of spatial resolution, accuracy and MS performance. With better ion and laser optics, and more mature methodologies, development of accurate sample positioning device is gaining importance. While piezoelectric devices have superb positioning accuracy (~50 nm), their range of motion is limited. """"""""Stacked-stages"""""""" with longer travels have a tradeoff in accuracy (~5 ?m) and speed, are bulkier and hard to implement in a vacuum environment. They also produce substantial RF interference, hence unsuitable for FT-ICR mass spectrometry. One phase of this work (Aizikov et al., 2009) presents a two-dimensional, vacuum compatible sample positioning stage capable of submicron accuracy with range of motion of 100x100 mm operating at ~1x10-8 mbar. It has been performed in collaboration with Ron Heeren's group at FOM Institute for Atomic and Molecular Physics (AMOLF) in Amsterdam. To test the capabilities of this stage as a proof of principle, a custom built FT-ICRMS imaging instrument was equipped with the device (built and operated in Ron Heeren's group). BUSM graduate student Kostya Aizkhov participated in the analyses. The spatial resolution of individual peptides was assessed via a fully automated MALDI imaging experiment in a microprobe mode. Performance evaluation and experimental results show that characteristics of the device easily meet MALDI FT-ICR MS imaging requirements in terms of positioning accuracy, speed, robustness, and RF interference. It is compatible with most of the ionization sources in terms of size and vacuum requirements. Even though the stage will work in the majority of SIMS imaging experiments, further improvements in accuracy (possible through the use of lower wavelength optical linear encoders) would allow this device to be used for virtually every need of contemporary imaging mass spectrometry. Journal publications and a PhD thesis were completed. At BUSM, the MALDI-FTMS system was updated and tested for use with both protein/peptide samples and lipids separated on TLC plates. Repairs have been made and components have been refined so that further investigations of this area can be carried out in the coming year.
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