Evaluation of a new low sheath-flow interface for CE-MS

Area of Science:

• Analytical Chemistry
• Separation Science

Background:

• Increasing technical complexity in CE-ESI-MS interfaces necessitates simpler, more accessible alternatives.
• Existing interfaces often involve complex setups and nebulizing gas, leading to sample dilution and efficiency loss.

Purpose of the Study:

• To evaluate a simple, low sheath-flow electrospray ionization (ESI) interface for capillary electrophoresis-time of flight/mass spectrometry (CE-TOF/MS).
• To assess the performance of a submicroliter nanospray regime without nebulizing gas assistance.
• To investigate the impact of operational parameters on interface performance.

Main Methods:

• Developed and evaluated a low sheath-flow ESI interface operating in the submicroliter nanospray regime.
• Studied the effects of sheath liquid composition and flow rate, working distance, and ESI potential.
• Performed simulations of mixing processes within the Taylor cone to understand band broadening.
• Applied the interface to analyze basic drugs using CE-TOF/MS.

Main Results:

• The sheath liquid improved analyte ionization, while the absence of nebulizing gas minimized sample dilution and efficiency loss.
• Taylor cone size was identified as critical for band broadening.
• Achieved limits of detection in the 25-100 ppb range for basic drugs.
• Demonstrated suitable robustness and repeatability.

Conclusions:

• The developed ESI interface is simple, accessible, and offers good performance for CE-MS applications.
• This design provides a viable alternative to more complex and expensive interfaces.
• The interface enables sensitive and reliable analysis of basic drugs.