Can MSI measure proteins?

Yes, but mainly accomplished by MALDI (matrix-assisted soft ionization), which is the main force for spatializing tissue proteomics; SIMS can also measure them but easily fragments.

Can small-molecule drugs be measured by MSI?

Yes, and it is a mature range. Matrix-free ambient sources (LDPI/DPI/DESI) have a clean background in the low-mass region, suitable for imaging the distribution of drugs and metabolites.

Which molecules does SIMS exclusively excel at?

Elements, inorganic ions and surface chemistry, and TOF-SIMS can reach the nanometer scale, a unique means for materials and biomineralization research.

Can one source measure all molecules?

No. Small molecules lean toward ambient matrix-free sources, large proteins lean toward MALDI, and nanometer-scale elements lean toward SIMS; multiple sources are often combined by target molecule.

Search Query · Mass Spectrometry Imaging

Which target molecules can mass spectrometry imaging detect?

Mass spectrometry imaging can detect almost any molecule that 'can be ionized and brought into the mass analyzer,' covering a broad range from elements, metabolites, lipids, drugs and peptides to proteins. But what exactly can be measured depends on the ionization mechanism and mass window of the chosen ion source—no single source covers everything.

Table of Contents
1. Small molecules: metabolites, lipids, drugs 2. Medium mass: peptides and sugars 3. Large molecules: proteins and nucleic acids 4. Elements and surface chemistry

Which target molecules can mass spectrometry imaging detect? — schematic diagram

1. Small molecules: metabolites, lipids, drugs

Metabolites, lipids and the vast majority of small-molecule drugs (mostly m/z below 1000) are best suited to matrix-free ambient sources (DESI, LDPI, DPI). LDPI presents small molecules with a low background above m/z≥70 and matrix-free; DPI has sensitivity 1–4 orders of magnitude higher than DESI, and in negative/positive ion modes can newly detect over a hundred secondary metabolites.

In plant and herbal-medicine imaging, DPI has demonstrated sensitive detection of theanine (signal increased 14.5×), caffeine (61×), flavonoids, terpenes, etc., showing that small molecules are among the most mature application ranges of MSI.

2. Medium mass: peptides and sugars

Peptides, sugars and some medium-mass molecules are well presented by MALDI via matrix-assisted soft ionization, and can also be partly covered by ESI-derived sources (DESI). MALDI gives robust signals in this high-mass region.

For projects that need to see both peptides and small molecules, MALDI (peptides/proteins) and LDPI/DESI (small molecules) are often combined and registered to the same tissue.

3. Large molecules: proteins and nucleic acids

Large molecules such as proteins, peptides and nucleic acids (m/z thousands to tens of thousands) are mainly covered by MALDI and SIMS, among which MALDI is the most mature for intact protein/peptide imaging and is the main force for spatializing tissue proteomics.

SIMS can also measure large molecules but is a hard-ionization, easily fragmenting approach; ambient matrix-free sources (LDPI/DPI/DESI) lean toward small and medium molecules and are weak at imaging intact large proteins. Therefore 'wanting to see proteins' essentially points to MALDI.

4. Elements and surface chemistry

TOF-SIMS can also detect elements, inorganic ions and surface chemistry, a unique means for materials and biomineralization research with resolution down to the nanometer scale. This is the exclusive capability of SIMS compared with other sources.

Summary: small molecules / metabolites / drugs / lipids → DESI/LDPI/DPI; peptides/proteins → MALDI; nanometer-scale elements/lipids → SIMS. Choosing the source by target molecule is the first step in MSI method design.

Frequently Asked Questions (FAQ)

Can MSI measure proteins?: Yes, but mainly accomplished by MALDI (matrix-assisted soft ionization), which is the main force for spatializing tissue proteomics; SIMS can also measure them but easily fragments.
Can small-molecule drugs be measured by MSI?: Yes, and it is a mature range. Matrix-free ambient sources (LDPI/DPI/DESI) have a clean background in the low-mass region, suitable for imaging the distribution of drugs and metabolites.
Which molecules does SIMS exclusively excel at?: Elements, inorganic ions and surface chemistry, and TOF-SIMS can reach the nanometer scale, a unique means for materials and biomineralization research.
Can one source measure all molecules?: No. Small molecules lean toward ambient matrix-free sources, large proteins lean toward MALDI, and nanometer-scale elements lean toward SIMS; multiple sources are often combined by target molecule.

Get Specifications & Quotation

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).

MALDI DESI SIMS / TOF-SIMS Neo-Source MSI LDPI Laser Desorption Photoionization imaging ion source DPI Dual-Photoionization Imaging Source Metabolite Spatial Distribution: Letting Each Coordinate Point Carry a Set of Molecular Signals Spatial Lipidomics: Drawing the Lipid 'Map' in Tissue

← Back to MSI Ion Source Knowledge Hub