Large volume stacking using an EOF pump in NACE-MS.

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.
• Large volume stacking (LVSEP) is crucial for enhancing sensitivity in CE/ESI-MS.
• Traditional LVSEP methods face challenges with sample matrix plugs and interface compatibility.

Purpose of the Study:

• To develop and validate a robust LVSEP method for anions using CE/ESI-MS.
• To overcome the limitations of sample matrix plugs in anion LVSEP.
• To achieve significant enrichment in detection sensitivity without interface modification.

Main Methods:

• Implementation of a large volume stacking using an EOF pump (LVSEP) system for CE/ESI-MS.
• Utilized reverse polarity electroosmotic flow (EOF) to expel sample matrix plugs.
• Employed a simple setup with a backup run buffer vial and methanol as the run buffer solvent.
• Used a bare fused-silica capillary to achieve suppressed EOF.

Main Results:

• Successfully overcame adverse effects of long sample matrix plugs during anion LVSEP.
• Achieved a 400-fold enrichment in detection sensitivity for six anionic analytes.
• Demonstrated the applicability of the method using a conventional sheath liquid CE/ESI-MS interface.
• Showcased the effectiveness of suppressed EOF with methanol as the run buffer solvent.

Conclusions:

• The developed LVSEP method is effective for enhancing sensitivity in CE/ESI-MS for anionic analytes.
• The technique offers a simple and efficient solution for matrix plug issues in LVSEP.
• This approach provides a significant improvement in detection limits without requiring specialized equipment or interface modifications.