A High-Lateral Resolution MALDI Microprobe Imaging Mass Spectrometer Utilizing an Aspherical Singlet Lens

Abstract

E-mail: sanghan@kriss.re.krReceived September 24, 2012, Accepted October 31, 2012We report the construction of a MALDI imaging mass spectrometer equipped with a specially designed laserfocusing lens, a compact aspherical singlet lens, that obtains a high-lateral imaging resolution in the microprobemode. The lens is specially designed to focus the ionization laser ( λ = 355 nm) down to a 1 μm diameter witha long working distance of 34.5 mm. With the lens being perpendicular to the sample surface and sharing theoptical axis with the ion path, the imaging mass spectrometer achieved an imaging resolution of as good as 5μm along with a high detection sensitivity of 100 fmol for peptides. The mass resolution was about 900 (m/Δm) in the linear TOF mode. The high-resolution capability of this instrument will provide a new researchopportunity for label-free imaging studies of various samples including tissues and biochips, even for the studyat a single cell level in the future.Key Words : Imaging mass spectrometry, High-lateral resolution, MALDI IntroductionDue to its promising potential for bioclinical applications,including biomarker discovery and disease diagnosis, matrix-assisted laser desorption/ionization (MALDI) mass spectro-metric imaging has been being actively developed in recentyears.