Mass spectrometry imaging properties

The second key requirement for an imaging techniques is a contrast mechanism, which is some property of the system that varies spatially in the same way as the sample properties to be mapped, e.g. a specific fragment in mass spectrometry, a specific vibrational group frequency, surface reflectivity, etc. In many cases, especially for polymers, samples do not have much inherent contrast under a visible light microscope. Additional contrast is desired. 

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