Shaping electrospray plume with convergent sound beams

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Materials Science

Background:

• Electrospray ionization (ESI) is a key technique in mass spectrometry (MS).
• Controlling microdroplet behavior in ESI is crucial for optimizing analytical performance.
• Existing ESI methods lack fine-tuned control over droplet dynamics.

Purpose of the Study:

• To introduce and investigate a new ESI-MS setup utilizing orthogonal sound waves.
• To explore the effect of sound waves on electrospray microdroplets of varying sizes.
• To demonstrate the modulation of the electrospray process using acoustic energy.

Main Methods:

• Developed a modified ESI-MS interface with an orthogonal sound source.
• Employed high-speed imaging to analyze microdroplet deflection by sound waves.
• Conducted online ESI-MS experiments with peptides, polymers, and amino acids.

Main Results:

• Low-frequency sound waves partially separate microdroplets based on size.
• Acoustic influence on microdroplets is more pronounced at higher amplitudes and lower frequencies.
• The study successfully demonstrated modulation of electrospray plume dynamics.

Conclusions:

• Orthogonal sound waves offer a novel method to control electrospray microdroplet motion.
• This acoustic modulation technique can enhance separation and control in ESI-MS.
• Findings have potential applications in mass spectrometry and materials science.