Improved sensitivity by post-column chemical environment modification of CE-ESI-MS using a flow-through microvial...

Area of Science:

• Analytical Chemistry
• Separation Science
• Mass Spectrometry

Background:

• Capillary electrophoresis coupled with electrospray ionization mass spectrometry (CE-ESI-MS) is a powerful analytical technique.
• Post-column chemical modification is crucial for optimizing detection sensitivity and signal appearance in CE-ESI-MS.
• The chemical environment of the modifier solution can significantly impact the analysis of specific analytes.

Purpose of the Study:

• To investigate the effect of acidic versus basic background electrolyte (BGE) compositions in the modifier solution on the detection of N-Acetylneuraminic acid (Neu5Ac) using CE-ESI-MS.
• To evaluate the impact of modifier pH on signal intensity, peak shape, and limit of detection (LOD) for Neu5Ac.

Main Methods:

• Capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) was employed.
• A flow-through microvial interface was used for post-column modification.
• The modifier solution was prepared using either an acidic or a basic background electrolyte (BGE).
• Signal intensity, peak shape, and limit of detection (LOD) of N-Acetylneuraminic acid (Neu5Ac) were analyzed.

Main Results:

• A basic modifier significantly improved Neu5Ac detection in negative ion mode compared to an acidic modifier.
• The basic modifier resulted in increased sensitivity and more symmetrical peak shapes.
• The limit of detection (LOD) for Neu5Ac was 5.20 nM with a basic modifier, compared to 47.7 nM with an acidic modifier.
• Peak asymmetry factors were closer to ideal (1.0) with the basic modifier (1.0–1.1) than with the acidic modifier (0.71–1.5).

Conclusions:

• The choice of post-column chemical modifier composition critically influences CE-ESI-MS performance.
• Utilizing a basic modifier optimizes the detection of N-Acetylneuraminic acid (Neu5Ac), leading to enhanced sensitivity and peak symmetry.
• Properly selected post-column modification strategies are essential for maximizing the effectiveness of CE-MS systems.