Electronic coupling and scaling effects during dielectric barrier electrospray ionization

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Mass Spectrometry

Background:

• Dielectric barrier electrospray ionization (DB-ESI) is a novel technique with potential analytical applications.
• A detailed understanding of the underlying physical and chemical mechanisms is crucial for optimizing DB-ESI performance.
• Previous studies have introduced DB-ESI, but a deeper investigation into its operational principles was needed.

Purpose of the Study:

• To investigate the fundamental mechanism of dielectric barrier electrospray ionization (DB-ESI) in greater detail.
• To identify and explain the sub-processes contributing to the observed current signals during DB-ESI.
• To evaluate the influence of various parameters on the spray characteristics and analytical output.

Main Methods:

• Detailed investigation of the dielectric barrier electrospray ionization (DB-ESI) process.
• Analysis of two independent current signals generated during DB-ESI to elucidate sub-processes.
• Systematic study of the impact of high-voltage (HV) signal modulation, applied frequency, and emitter capillary inner diameter on the spray.

Main Results:

• Two distinct current signals during DB-ESI were identified and attributed to specific sub-processes.
• Spray characteristics are significantly influenced by the modulated HV signal shape, applied frequency, and emitter capillary diameter.
• A cut-off frequency, dependent on the electronic properties of the DB-ESI interface, was observed.

Conclusions:

• The study provides a more comprehensive understanding of the dielectric barrier electrospray ionization (DB-ESI) mechanism.
• Key operational parameters affecting the DB-ESI spray have been identified, enabling potential optimization.
• Mass spectra of lysine obtained via DB-ESI are comparable to those from conventional electrospray ionization (ESI), indicating good analytical potential for the new technique.