First-Principles Modeling of Preferential Solvation in Mixed-Modifier Differential Mobility Spectrometry

Area of Science:

• Analytical Chemistry
• Physical Chemistry

Background:

• Differential mobility spectrometry (DMS) separates ions based on their mobility in varying electric fields.
• Solvents like water and acetonitrile enhance DMS resolution by altering ion clustering behavior.
• Binary solvent mixtures can exhibit dominant solvent effects, influencing ion trajectories.

Purpose of the Study:

• To investigate the dominance of one solvent over another in binary solvent mixtures within DMS.
• To explore the underlying principles governing solvent dominance using a first-principles model.
• To guide the use of binary solvent mixtures for improved ion separations and solvent binding energy scales.

Main Methods:

• Utilized a first-principles model of Differential Mobility Spectrometry (DMS).
• Simulated analytes in single and binary solvent mixtures.
• Computed DMS dispersion curves and predicted cluster populations.

Main Results:

• Computed DMS dispersion curves for quinoline derivatives closely matched experimental data.
• Predicted cluster populations revealed preferential solvation by the stronger binding solvent in mixed environments.
• Demonstrated that solvent binding strength is a key factor in solvent dominance.

Conclusions:

• First-principles modeling accurately predicts DMS behavior in mixed solvent environments.
• Binary solvent mixtures offer a method to enhance ion separation for coeluting compounds.
• The study provides a basis for creating a relative scale of solvent binding energies.