title: Laser beam filtration for high spatial resolution MALDI imaging mass spectrometry.
abstract: We describe an easy and inexpensive way to provide a highly defined Gaussian shaped laser spot on target of 5 μm diameter for imaging mass spectrometry using a commercial MALDI TOF instrument that is designed to produce a 20 μm diameter laser beam on target at its lowest setting. A 25 μm pinhole filter on a swivel arm was installed in the laser beam optics outside the vacuum ion source chamber so it is easily flipped into or out of the beam as desired by the operator. The resulting ion images at 5 μm spatial resolution are sharp since the satellite secondary laser beam maxima have been removed by the filter. Ion images are shown to demonstrate the performance and are compared with the method of oversampling to achieve higher spatial resolution when only a larger laser beam spot on target is available.
authors: Department of Biochemistry, Mass Spectrometry Research Center, National Research Resource for Imaging Mass Spectrometry, Vanderbilt University, Nashville, TN, USA.
authors: Andre
authors: A
authors: Zavalin
authors: Junhai
authors: J
authors: Yang
authors: Richard
authors: R
authors: Caprioli
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology; D001923:Brain Chemistry; D004867:Equipment Design; D005374:Filtration / Q000295:instrumentation; D007834:Lasers; D051379:Mice; D057054:Molecular Imaging / Q000295:instrumentation / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods*
references: J Mass Spectrom. 2006 Jun;41(6):705-16
references: 16718638
references: Nature. 1975 Jul 10;256(5513):119-20
references: 1152979
references: J Proteomics. 2012 Aug 30;75(16):5077-5092
references: 22469858
references: J Mass Spectrom. 2012 Nov;47(11):1473-81
references: 23147824
references: Rapid Commun Mass Spectrom. 2008 Sep;22(18):2779-90
references: 18697229
references: J Am Soc Mass Spectrom. 2005 Oct;16(10):1654-9
references: 16095912
references: Anal Chem. 1997 Dec 1;69(23):4751-60
references: 9406525
references: J Am Soc Mass Spectrom. 2002 Jun;13(6):735-48
references: 12056573
references: J Am Soc Mass Spectrom. 2007 Sep;18(9):1646-52
references: 17659880