High Spatial Resolution MALDI Imaging Mass Spectrometry Data Acquisition
Jamie Allen, Jeff Spraggins, Angela R.S. Kruse, David Anderson, allison.b.esselman, Martin Dufresne, Katerina V Djambazova, Madeline E. Colley, Melissa Farrow, Ali Zahraei, Olof Isberg
Abstract
This protocol provides the workflow and instrument parameters for setting up a MALDI imaging mass spectrometry experiment on a Bruker timsTOF Flex instrument. This protocol is intended for 10µm spatial resolution imaging of lipids ( m/z 400 - 2000) in positive and negative ionization mode data acquisition in qTOF mode of operation.
Steps
Place slides in a MTP 2-slide holder. Scan slides using flatbed scanner, allowing for sufficient contrast to visualize the tissue boundary. Ensure the slides have fiducials.
Load the 2-slide holder in the instrument. Open timsControl software and select appropriate MALDI IMS data acquisition method. Generate target profile by ensuring "Use Target Profile" is enabled. Check the height at a few different locations on the slide and ensure the difference is <10 µm.
Calibrate the TOF with an external calibration using red phosphorus. Proceed if all calibration points are <1ppm standard deviation error and the calibration score is >99%.
Use the FlexImaging software to load the optical image of the slides. Teach the target position with three teaching points. Check the accuracy of the teaching by moving the stage to a fourth location.
Select desired tissue measurement region. Start data acquisition in the FlexImaging software.
