COSAM » Departments » Chemistry & Biochemistry » Facilities » massspec » Learn about mass spectrometry » MALDI-TOF » Ionization

As the target enters the instrument at atmospheric pressure (1013 mbar), a vacuum pump is initiated to bring the pressure down to 2 mbar, then the turbo molecular pump decreases the pressure to about 2e-8 mbar (very high vacuum).  In comparison, a household vacuum cleaner operates at around 200 mbar.
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The instrument contains both a laser (blue arrow) and camera (gray arrow).  The camera allows the user to view the target spot as the laser is shining (or firing) on the target.
maldi laser fire
This is a cartoon of the ionization where the first step consists of the laser hitting the sample and matrix.
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The laser is thought to provide excitation and vibration energy to the matrix causing it to come off the target (visible with the camera) and some of the ions begin to move through a series of lenses into the Time of Flight tube.


Last Updated: 01/07/2020