Sheathless capillary electrophoresis-mass spectrometry using a pulsed electrospray ionization source

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Capillary electrophoresis (CE) coupled with mass spectrometry (MS) is a powerful analytical technique.
• Traditional interfaces can suffer from column clogging, especially with conductive coatings.
• Electrospray ionization (ESI) is a common ionization method for CE-MS.

Purpose of the Study:

• To develop and evaluate a novel sheathless interface for CE-ESI-MS.
• To address the issue of column clogging in CE-MS analyses.
• To improve signal stability and sensitivity in CE-MS.

Main Methods:

• Development of a sheathless interface utilizing a pulsed electrospray ionization (ESI) source.
• Optimization of pulsed ESI parameters (20 Hz, 20% duty cycle).
• Coupling the pulsed ESI interface with a CE system and an ion trap (IT) mass spectrometer.

Main Results:

• The pulsed ESI source with a larger orifice alleviated column clogging issues.
• Optimal pulsed ESI operation at 20 Hz and 20% duty cycle yielded enhanced signals.
• Setting ion injection time close to spraying time (10 ms) improved signal quality.
• A sprayer with a 50 µm OD provided more stable and enhanced signals compared to continuous ESI-MS.

Conclusions:

• The developed sheathless interface with a pulsed ESI source is effective for CE-MS.
• This approach offers improved stability and signal enhancement, overcoming common interface limitations.
• The method is suitable for the analysis of synthetic drugs using CE-MS.