Mass spectrometry sampling under ambient conditions with desorption electrospray ionization

Area of Science:

• Analytical Chemistry
• Surface Science
• Mass Spectrometry

Background:

• Traditional mass spectrometry techniques often require sample preparation.
• Analyzing compounds directly on surfaces presents analytical challenges.
• Electrospray ionization (ESI) is a powerful technique but typically requires samples in solution.

Purpose of the Study:

• To introduce and characterize a new desorption ionization method.
• To demonstrate the applicability of this method for analyzing various compounds on different surfaces.
• To explore the potential for in vivo analysis using this technique.

Main Methods:

• Desorption electrospray ionization (DESI) was employed.
• Charged solvent droplets and ions were directed onto sample surfaces.
• Analysis of resulting gaseous ions was performed using mass spectrometry.

Main Results:

• DESI successfully ionized diverse compounds, including nonpolar small molecules, polar compounds, peptides, and proteins.
• The technique was effective on conductive and insulator surfaces (metal, polymer, mineral).
• Generated mass spectra closely resembled those from conventional ESI, showing molecular ions.

Conclusions:

• DESI is a versatile desorption ionization technique for surface analysis.
• The method allows for direct analysis of analytes in complex matrices, including biological samples.
• DESI holds promise for in vivo applications and analyzing compounds on various substrates.