Electrospray ionization stability and concentration sensitivity in capillary electrophoresis-mass spectrometry using...

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Concentration sensitivity is crucial for analytical techniques like capillary electrophoresis-mass spectrometry (CE-MS).
• Electrospray ionization (ESI) stability and detection sensitivity are key performance indicators in CE-MS.
• Optimizing the interface between CE and MS is essential for improving analytical performance.

Purpose of the Study:

• To develop and evaluate a flow-through microvial interface for coupling CE with MS.
• To enhance ESI stability and improve detection sensitivity in CE-MS analyses.
• To assess the performance of the interface for quantifying amino acids and peptides.

Main Methods:

• Coupling CE with MS using a flow-through microvial interface.
• Mapping MS signal intensity by infusing a peptide mixture through the interface.
• Conducting finite element simulations to analyze electric field strength near the emitter tip.
• Evaluating key performance indicators (LOD, linearity, reproducibility) across four MS platforms.

Main Results:

• The flow-through microvial interface demonstrated stable ESI with no significant signal loss within a defined region (6 × 6.5 × 5 mm).
• Finite element simulations confirmed that minor emitter tip location changes minimally affected electric field strength.
• The interface showed suitable limits of detection and linearity for nine amino acids and five peptides.
• Inter- and intraday reproducibility were found to be acceptable for quantification when using internal standards.

Conclusions:

• The flow-through microvial interface effectively couples CE with MS, enhancing ESI stability and detection sensitivity.
• The interface is suitable for the reliable quantification of amino acids and peptides.
• This approach offers a robust solution for improving CE-MS performance in various analytical applications.