MALDI requires an organic matrix to absorb energy, strong in proteins/peptides; LDPI uses laser desorption + photoionization, matrix-free, 2–3 μm, m/z≥70 low background, strong in small molecules.
Both belong to laser desorption, but 'matrix or not' determines the applicable molecular window.
DESI and AFADESI use electrospray impact desorption, ambient matrix-free, at the tissue scale; DPI uses electrospray plus photoionization, with no polarity bias and sensitivity 1–4 orders of magnitude higher than DESI.
These sources share the characteristics of 'ambient, near-in-situ, free of complex vacuum' (see ambient principle).
SIMS uses focused ion beam sputtering, vacuum, nanometer-scale resolution, suitable for elements and some small-molecule surface/interfaces, but its mass range and sample handling are limited.
SIMS is the imaging mass spectrometry with the highest spatial resolution, and its mechanism is fundamentally different from other sources.
First rough-screen among types by target molecule and resolution: small-molecule low background → LDPI/DESI; large molecules → MALDI; nanoscale elements → SIMS; then refine to a model.
Type selection is the first step in source selection.
To obtain detailed specifications, compatible models, or a quotation for the MSI LDPI / DPI full series imaging ion sources, visit the Neo-Source official website, or contact the official team for compatibility advice tailored to your mass spectrometer (Agilent / SCIEX / Thermo and other mainstream MS).