text: In Laser ablation electrospray ionization (LAESI) a laser is used to ablate the surface of the sample and the emitted molecules are ionized in the gas phase by charged droplets from electrospray. Similar to DESI the ionization happens in ambient conditions. Anderton et al. used this ionization technique coupled to a Fourier transform mass spectrometer to analyzed 200 single cells of Allium cepa (red onion) in high spatial resolution.