SIMS bombards the sample with a focused primary ion beam (such as Ga+, Bi3+ clusters), which can be focused to sub-micrometer or even nanometer scale; each bombardment point is a pixel, so the resolution is determined by the ion beam size and can indeed reach the nanometer scale.
This is exactly why it is irreplaceable in materials science, organelles and lipid-raft research: no other MSI source (MALDI at several micrometers, DESI/LDPI from tens of micrometers down to 2–3 μm (among the leading in the industry)) can reach this scale.
SIMS is a hard-ionization technique: the high-energy bombardment of primary ions sputters molecules and causes severe fragmentation, so proteins, peptides and other large molecules have their structures destroyed during sputtering and are difficult to detect as intact molecular ions.
Therefore SIMS has weak capability for intact protein imaging and is more used for elements, inorganic ions, lipids and small-molecule metabolites. For spatial distribution of intact proteins or peptides, MALDI remains the primary choice.
SIMS exclusive strengths lie in elements and surface chemistry (materials, biomineralization, semiconductor doping) and nanometer-scale lipid distribution. It can characterize lipid heterogeneity at the single-cell and even subcellular level.
SIMS can also handle nanometer-scale distribution of drugs or metabolites, but one must note the fragment complexity brought by hard ionization; matrix-free ambient sources (LDPI 2–3 μm (among the leading in the industry)) cover single-cell-scale small molecules with a lower threshold.
When your question truly needs nanometer-scale spatial resolution (such as organelle localization, material surface chemistry, lipid rafts) and the target is elements, lipids or small molecules, SIMS is the first choice.
If the target is intact protein or peptide distribution, or ambient matrix-free rapid imaging is needed, one should turn to MALDI or LDPI/DPI. The three are used in combination by scale plus molecule type, not as substitutes for each other.
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).