Related Experiment Video
Updated: Mar 28, 2026

Imaging of Biological Tissues by Desorption Electrospray Ionization Mass Spectrometry
Published on: July 12, 2013
Improved desorption/ionization and ion transmission in surface scanning by direct analysis in real time mass
Tim T Häbe1, Gertrud E Morlock1
1Interdisciplinary Research Center (IFZ) and Institute of Nutritional Science, Chair of Food Science, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
Rationale:
Modifications to the Direct Analysis in Real Time mass spectrometry (DART-MS) interface, its source cap and transfer tube were necessary to obtain highest efficiency in desorption and ionization from the sampling surface and in ion transmission into the MS system. These issues are crucial for the trace analysis of any surface and the hyphenation of high-performance thin-layer chromatography (HPTLC) with DART-MS.
Methods:
The ion source mounting was modified to enable short source caps to be utilized in combination with a short transfer tube. The grid voltage contact section was readjusted to increase the intensity of the metastable gas stream towards the substrate. Eighteen different cap and two transfer tube geometries (including gas-stream focusing), along with the influence of their distance from the mass spectrometer glass capillary, were investigated for best signal intensity.
Results:
Using shortened source caps with staged inner bore, a transfer tube with gas-stream focusing and an optimized mounting geometry for DART-MS scanning along five identical deposited bands (600 ng each) of butyl 4-hydroxybenzoate, an average signal precision of 3.6% was obtained and the signal intensity was increased by a factor of 34. The width of the gas impact area did not exceed 1.5 mm and the smallest FWHM was determined to be 0.9 mm.
Conclusions:
The desorption strength, ionization efficacy and ion transmission were improved significantly giving increased detectability using this further modified DART-MS interface with reduced cap length and optimum transfer tube geometry. The resolution was comparable with state-of-the-art densitometry. With this setup, reliable HPTLC surface scanning is possible, even for substance amounts in the low-nanogram range.
More Related Videos
07:53Analysis of Complex Molecules and Their Reactions on Surfaces by Means of Cluster-Induced Desorption/Ionization Mass Spectrometry
Published on: March 1, 2020
12:11Simultaneous Affinity Enrichment of Two Post-Translational Modifications for Quantification and Site Localization
Published on: February 27, 2020
Related Concept Videos
Electrospray Ionization (ESI) Mass Spectrometry
ESI utilizes electrical energy to transfer ions from the liquid phase of the sample into the...
Mass Spectrum: Interpretation
Tandem Mass Spectrometry
Mass Spectrometers
MALDI-TOF Mass Spectrometry
Mass Spectrometry: Complex Analysis
GC–MS is a powerful hyphenated method commonly used in forensics and environmental...