Molecular ionization from carbon nanotube paper

Area of Science:

• Analytical Chemistry
• Materials Science

Background:

• Ambient ionization techniques enable mass spectrometry analysis without complex sample preparation.
• Carbon nanotubes (CNTs) possess unique electrical and nanoscale properties suitable for advanced analytical applications.

Purpose of the Study:

• To develop a simple and effective ambient ionization source for mass spectrometry.
• To investigate the mechanism of ionization using CNT-impregnated paper.

Main Methods:

• Utilizing a carbon nanotube-impregnated paper as an ambient ionization source.
• Applying low voltages (≥3 V) to induce ionization and spraying.
• Analyzing organic molecules in positive and negative ion modes using mass spectrometry.
• Microscopic and Raman spectroscopy to characterize the CNT paper and current flow.

Main Results:

• Achieved simple, high-quality mass spectra of organic molecules with minimal fragmentation.
• Demonstrated effective ionization for both volatile and nonvolatile compounds across diverse matrices.
• Identified field emission of microdroplets as the likely ionization mechanism, distinct from conventional field ionization.
• Confirmed nanoscale features of CNT paper contribute to high electric fields and substantial current flow.

Conclusions:

• The CNT-impregnated paper serves as a robust and versatile ambient ionization source.
• This technique offers a promising alternative for rapid and sensitive analysis of organic compounds.
• The findings highlight the potential of nanomaterials in advancing mass spectrometry instrumentation.