FlexESI: An Automated Vapor-Switching Interface for Enhanced Flexibility and Sensitivity in Electrospray Ionization

Area of Science:

• Analytical Chemistry
• Mass Spectrometry

Background:

• Improving electrospray ionization (ESI) mass spectrometry (MS) performance often involves sample additives.
• Gaseous additives can be introduced directly into the electrospray plume.
• Conventional methods typically allow only one additive at a time.

Purpose of the Study:

• To develop a flexible automated system for dynamic switching of multiple gas-phase additives in ESI-MS.
• To investigate the impact of different gaseous additives (acids, solvents) on analyte signal enhancement.
• To optimize analyte detection and structural probing through controlled additive dosing.

Main Methods:

• Development of an automated system for dynamic switching of gas-phase additives.
• Introduction of various acid and solvent vapors into the ion source compartment.
• Systematic variation of additive type and concentration.
• Application in real sample analysis coupled with liquid chromatography.

Main Results:

• Demonstrated dynamic switching among several gas-phase additives.
• Observed analyte signal enhancement factors ranging from approximately 2 to 15.
• Showcased improved signal intensities and broadened detection ranges in real samples.
• Validated controlled dosing for optimizing protein signal and facilitating structural probing.

Conclusions:

• The automated system significantly enhances the analytical performance and versatility of ESI-MS.
• Dynamic switching of gas-phase additives offers a flexible and powerful approach for analyte signal optimization.
• Controlled dosing enables tailored optimization for specific analytes and structural studies.