below for denition) fragment ions at m/z 575, 601 and 603 (Fig. 5). Importantly, the Pd-NP-assisted LDI material generated mostly the intact TAG species without major fragmentation, as opposed to MALDI, where extensive fragmentation was seen for TAG species22 (Fig. S4 shows an example of a MALDI-MS analysis of cold-extracted olive oil in our experiments, showing extensive formation of “DAG-like” fragments from protonated precursor ions; see ESI†). Gidden et al. demonstrated47 for sodiated TAGs that fragmentation levels in MALDI could be strongly reduced by adding base to the sample/matrix, to remove catalyzing H+ ions form the matrix and preventing formation of protonated TAGs. The “DAG-like” fragments as described by Gidden et al.47 corresponded to losses of RCOOH and RCOONa from the protonated and sodiated TAGs, giving rise to ions in the m/z range of 573 to 627. Similar decompositions were seen by Calvano et al. for TAGs in LDITOF. 31 In Pd-NP-assisted LDI in our experiments, only minor fragments in the same region were formed from losses of RCOOK (Fig. 5).