In total, 400 shots were collected from each ablaWon point with 20 shots at the raster spot, and the laser focus diameter was set to "3_medium". FlexControl version 3.4 (Bruker-Daltonics, Bremen, Germany) was employed for spectra acquisiWon, and FlexImaging, version 4.0 was used for data processing and the creaWon of molecular images. FlexAnalysis (version 3.4) was used for the spectra analysis. All the data were normalised to TIC. MS spectra that were subjected to NEDC analysis were recalibrated internally using selected peaks.