Influence of mobile phase, source parameters and source type on electrospray ionization efficiency in negative ion...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Separation Science

Background:

• Electrospray ionization (ESI) efficiency is crucial for analyte detection in mass spectrometry.
• Factors influencing ESI efficiency include analyte properties, source design, and operational parameters.
• Understanding these factors is key to optimizing analytical methods.

Purpose of the Study:

• To evaluate the electrospray ionization efficiency of 17 acidic compounds in negative ion mode.
• To investigate the influence of organic solvent content, source parameters, geometry, and functionality on ESI efficiency.
• To compare conventional ESI, ESI with thermal focusing, and ESI with an internal nebulizer gas.

Main Methods:

• Systematic evaluation of ionization efficiency for 17 acidic compounds.
• Experiments conducted using ESI in negative ion mode.
• Variations in mobile phase organic solvent content, ionization source parameters, and source configurations were tested.

Main Results:

• Thermal focusing ESI demonstrated marginal sensitivity to organic solvent composition.
• Conventional ESI and ESI with internal nebulizer gas showed significantly increased ionization efficiency with higher organic modifier content.
• Good correlation was observed in ionization efficiency values across different setups and mobile phase compositions.

Conclusions:

• Source design significantly impacts the dependence of ESI efficiency on mobile phase composition.
• Thermal focusing offers a more robust approach regarding organic solvent variations.
• These findings aid in selecting optimal ESI configurations for acidic analytes.