A sheathless CE/ESI-MS interface with an ionophore membrane-packed electro-conduction channel

Area of Science:

• Analytical Chemistry
• Separation Science
• Mass Spectrometry

Background:

• Sheathless interfaces for CE/ESI-MS offer higher sensitivity but often suffer from instability and short lifetimes due to poor electrical contact.
• Existing sheathless designs struggle with emitter tip integrity and consistent electrical conductivity.

Purpose of the Study:

• To develop a robust and convenient sheathless CE/ESI-MS interface with improved stability and longevity.
• To overcome the limitations of conventional sheathless interfaces by ensuring reliable electrical contact without compromising analyte flow.

Main Methods:

• Designed a sheathless interface incorporating an ionophore membrane-packed electro-conduction channel at the CE-emitter junction.
• Integrated a platinum wire electrode externally to the conduction channel for stable electric field transfer.
• Utilized finger-tight fittings for easy capillary replacement and minimized dead volume.

Main Results:

• Achieved stable electrospray for extended periods without bubbling or emitter tip damage.
• Demonstrated sensitive and stable CE-MS detection of model compounds like creatinine and uric acid.
• Confirmed no significant increase in dead volume with well-aligned capillaries.

Conclusions:

• The developed ionophore membrane-based sheathless CE/ESI-MS interface provides a stable and sensitive platform for mass spectrometry detection.
• This innovative design addresses key challenges in sheathless interfaces, enabling reliable and long-term operation.
• The interface facilitates convenient setup and maintenance, making it a valuable tool for CE-MS applications.