Electrospray ionization with a pointed carbon fiber emitter

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Materials Science

Background:

• Mass spectrometry (MS) requires efficient ionization of analytes.
• Nanoliquid sampling techniques present challenges for interfacing with MS.
• Existing electrospray ionization (ESI) emitters have limitations in efficiency and robustness.

Purpose of the Study:

• To develop a new electrospray ionization emitter for improved nanoliquid sampling.
• To enhance detection limits in mass spectrometry.
• To create a robust and versatile interface for liquid chromatography-mass spectrometry.

Main Methods:

• Fabrication of a pointed carbon fiber emitter with a hydrophobic surface.
• Confining a small Taylor cone at the emitter tip for stable electrospray generation.
• Testing the emitter with standard peptides (angiotensin I) and complex peptide mixtures (cytochrome c and myoglobin tryptic digests).
• Evaluating the emitter's performance in interfacing with monolithic capillary HPLC.

Main Results:

• The carbon fiber emitter generated a stable electrospray with improved efficiency and enhanced detection limits.
• Ion current comparable to commercial nanospray emitters was achieved.
• Sensitive protein identification (<1 fmol peptide consumed) using ESI-MS/MS was demonstrated.
• Successful interfacing of monolithic capillary HPLC to MS was shown.

Conclusions:

• The pointed carbon fiber emitter offers a rugged and efficient solution for nanoliquid sampling in mass spectrometry.
• This technology significantly enhances sensitivity for peptide analysis.
• The emitter facilitates seamless integration of HPLC with MS for complex sample analysis.