Matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI) of metabolites can reveal how metabolism is altered throughout heterogeneous tissues. Here negative ion mode MALDI-MSI has been coupled with laser post-ionisation (MALDI-2) and applied to the MSI of low molecular weight (LMW) metabolites (<m/z 600) to investigate the benefits MALDI-2 offers for spatial metabolomics in terms of metabolite coverage and sensitivity. When applied to mouse kidney tissue MALDI-2 …