Table 1.

Comparison of the three most commonly used MSI techniques.

Ionization type	Ionization source	Environment	Resolution	Characteristic	Ref.
MALDI	IR/UV	High vacuum/low vacuum	IR：150 μm UV: 10–250 μm	Need matrix, wide detection range	Heyman and Dubery (2016)
SIMS	Primary ion beam	High vacuum	50 nm–5 μm	High resolution, high vacuum, easy to produce fragments of ions	Behrens et al. (2012)
DESI	Charged corpuscle	Atmospheric pressure	100–200 μm	No matrix, atmospheric pressure	Ifa et al. (2007); Takáts et al. (2004); Wiseman et al. (2006)