Soft cluster-induced desorption/ionization mass spectrometry: How soft is soft?

Abstract

Desorption/ionization induced by neutral clusters (DINeC) is used as an ultrasoft desorption/ionization method for the analysis of fragile biomolecules by means of mass spectrometry (MS). As a test molecule, the glycopeptide vancomycin was measured with DINeC-MS, and resulting mass spectra were compared to the results obtained with electrospray ionization (ESI), matrix assisted laser desorption ionization, and time-of-flight secondary ion MS. Of the desorption-based techniques, DINeC spectra show the lowest abundance of fragments comparable to ESI spectra. The soft desorption nature of DINeC was further demonstrated when applied to MS analysis of teicoplanin.

Direct Analysis of Ion-Induced Peptide Fragmentation in Secondary-Ion Mass Spectrometry

“…Here, we make use of desorption/ionization induced by neutral SO 2 clusters (DINeC) in order to investigate ion-induced fragmentation in peptide samples. DINeC has been shown to be an extremely soft desorption method for molecules of various classes, for example, dyes, lipids, and proteins. − In particular for peptides, DINeC-MS yields clear, fragmentation-free spectra for easy identification of the molecular peaks. , The soft nature of the method is based on the low kinetic energy per SO 2 molecule in the clusters (≤0.8 eV/molecule), as employed by other soft desorption/sputtering methods, , in combination with the high dipole moment of SO 2 . Because of this high dipole moment, the SO 2 clusters serve as a transient matrix in the gas phase , and promote the desorption of polar molecules, despite the low E / n value.…”

Surface Properties of Ionic Liquids: A Mass Spectrometric View Based on Soft Cluster-Induced Desorption

“…This dissolvation process reduces the effective desorption barrier, 24 thus cluster-induced desorption is operative at comparably low beam energy, leading to the fragmentation-free nature of the desorption process. 21,22 Here, we demonstrate the application of DINeC-MS for the investigation of the surface composition of IL. Based on their negligible vapor pressure, 3,25,26 ILs allow for the investigation of liquid surfaces by means of particle-based analysis techniques such as mass spectrometry under high vacuum conditions.…”

“…Desorption/ionization induced by neutral clusters (DINeC), which exhibits extreme surface sensitivity, can be employed as a soft mass spectrometry (MS) technique. − DINeC is based on a low-energy beam of SO 2 clusters , in which the analyte molecules are dissolved during cluster-surface impact (Figure ). This dissolvation process reduces the effective desorption barrier, thus cluster-induced desorption is operative at comparably low beam energy, leading to the fragmentation-free nature of the desorption process. , …”

Cluster-Induced Desorption/Ionization of Polystyrene: Desorption Mechanism and Effect of Polymer Chain Length on Desorption Probability

“…Desorption/Ionization induced by Neutral Clusters (DINeC) is a nondestructive process that was applied for mass spectrometry of various types of organic molecules including peptides, proteins, lipids, and dyes. − It is based on the cluster-surface impact of SO 2 clusters with low energy density (<1 eV/molecule); thus, no covalent bonds are broken in the sample during cluster surface collision. As a consequence, DINeC-based mass spectrometry provides information on the intact sample molecules.…”