A Simple Sonication Improves Protein Signal in Matrix-Assisted Laser Desorption Ionization Imaging
Proper matrix application is crucial in obtaining high quality matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI). Solvent-free sublimation was essentially introduced as an approach of homogeneous coating that gives small crystal size of the organic matrix. However, sublimation has lower extraction efficiency of analytes. Here, we present that a simple sonication step after the hydration in standard sublimation protocol significantly enhances the sensitivity of MALDI MSI. This modified procedure uses a common laboratory ultrasonicator to immobilize the analytes from tissue sections without noticeable delocalization. Improved imaging quality with additional peaks above 10 kDa in the spectra was thus obtained upon sonication treatment.
KeywordsMatrix-assisted laser desorption ionization Mass spectrometry imaging sample preparation protein
This work was supported by Ministry of Science and Technology (MOST), R.O.C. (MOST 105-2113-M-002-004-MY2, 106-2113-M-002-013-MY2) and the Center for Emerging Material and Advanced Devices, National Taiwan University (NTU-ERP-106R880211, 106R880219). L.-E. Lin was supported by MOST grant 106-2813-C-002-136-M. The mass spectrometry data is available through https://www.space.ntu.edu.tw/navigate/s/92A5A683151D4AC2BC246C07D111A55CQQY .
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