What is the difference between DART and electrospray sources?

DART directly ionizes via gas plasma, not relying on liquid-phase nebulization; faster and more versatile, but spatial resolution and uniformity are inferior to spray/laser imaging sources.

Can DART do high-resolution imaging?

It can line-scan surfaces for 1D distribution, but 2D high-resolution imaging is not its strength; for precise 2D distribution prioritize MALDI/TOF-SIMS/DESI/LDPI.

What scenarios suit DART?

Rapid screening and in-situ identification of food, forensics, pharmacology, and material surfaces, as well as process monitoring; for biological-tissue multi-molecular imaging choose LDPI/DPI/DESI.

Technology Primer · Mass Spectrometry Imaging

DART Direct Analysis in Real Time Ionization

DART (Direct Analysis in Real Time) uses heated helium or nitrogen flow carrying plasma (containing excited species and ions) to directly ionize sample-surface molecules at atmospheric pressure, needing no chromatographic separation or complex preparation; it is a sample-and-measure ambient ionization technique, suiting rapid screening and in-situ sampling.

Table of Contents
Working Principle: Gas Plasma Direct Ionization Positioning in Ambient Sampling Suitable Scenarios and Performance Comparison with Matrix-Free Imaging Sources

DART Direct Analysis in Real Time Ionization — schematic diagram

Working Principle: Gas Plasma Direct Ionization

The DART source produces a warm gas flow containing excited helium/nitrogen, ions, and radicals that sweeps the sample surface, desorbing molecules and ionizing them via gas-phase reactions (such as proton transfer); ions are introduced into the analyzer. The whole process is completed in open air with almost no sample preparation.

Unlike electrospray, DART does not rely on liquid-phase nebulization but acts directly on solid/liquid/gas samples via gas plasma, thus extremely fast and versatile.

Positioning in Ambient Sampling

DART belongs to the ambient ionization family, alongside DESI, DBDI, and LDPI, emphasizing direct ionization in open environments. It can do rapid molecular identification of materials, food, drugs, documents, and even living surfaces.

Its advantage is speed and in-situ capability; but spatial resolution and uniformity are limited by gas-plume geometry, unsuitable as a high-resolution imaging main source.

Suitable Scenarios and Performance

DART is widely used for rapid screening of food safety, forensics, pharmacology, and material surfaces; it can line-scan surfaces for 1D distribution, but 2D high-resolution imaging is not its strength. It is valuable for single-point quick testing and process monitoring.

For imaging requiring subcellular or precise 2D distribution, prioritize MALDI, TOF-SIMS, DESI/LDPI, etc.; DART is better for quick screening plus identification.

Comparison with Matrix-Free Imaging Sources

DART, like LDPI/DPI and DESI, belongs to the ambient in-situ route but differs in ionization mechanism (gas plasma vs photochemical/electrospray). For surface contaminants, additives, and small-molecule quick screening, DART is direct and effective; for biological-tissue multi-molecular imaging, the LDPI/DPI/DESI ecosystem is more mature.

Selection should combine sample form, resolution needs, and whether 2D imaging is needed; the ambient matrix-free line can also evaluate DART as a supplementary quick-screening means.

Frequently Asked Questions (FAQ)

What is DART?: Direct Analysis in Real Time ionization: uses heated helium/nitrogen plasma to directly ionize sample-surface molecules at atmospheric pressure, needing no chromatography or complex preparation; sample-and-measure.
What is the difference between DART and electrospray sources?: DART directly ionizes via gas plasma, not relying on liquid-phase nebulization; faster and more versatile, but spatial resolution and uniformity are inferior to spray/laser imaging sources.
Can DART do high-resolution imaging?: It can line-scan surfaces for 1D distribution, but 2D high-resolution imaging is not its strength; for precise 2D distribution prioritize MALDI/TOF-SIMS/DESI/LDPI.
What scenarios suit DART?: Rapid screening and in-situ identification of food, forensics, pharmacology, and material surfaces, as well as process monitoring; for biological-tissue multi-molecular imaging choose LDPI/DPI/DESI.

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).

DESI Neo-Source MSI LDPI Laser Desorption Photoionization imaging ion source DPI Dual-Photoionization Imaging Source DBDI Dielectric Barrier Discharge Ionization Ambient Operation (Ambient Operation)

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