Conducting and characterizing femto flow electrospray ionization

Area of Science:

• Analytical Chemistry
• Mass Spectrometry

Background:

• Electrospray ionization (ESI) is a crucial technique in mass spectrometry.
• Achieving and controlling ultra-low flow rates in ESI presents significant challenges.

Purpose of the Study:

• To investigate femto flow electrospray ionization (ESI) at flow rates from 240 fL min^-1 to <10 pL min^-1.
• To characterize analyte ion behavior and enable nanodroplet size determination at these low flow rates.

Main Methods:

• Utilized a submicron emitter tip and a relay ESI configuration.
• Conducted measurements at femto and pico liter per minute flow rates.
• Analyzed signature analyte ion current intensities and profiles.

Main Results:

• Successfully performed ESI at femto flow rates (240 fL min^-1 to <10 pL min^-1).
• Observed distinct analyte ion current intensities and profiles.
• Enabled the calculation of initial charged nanodroplet sizes based on flow rate and ionization current.

Conclusions:

• Femto flow ESI is feasible and provides measurable ion signals.
• The technique allows for the characterization of ion behavior and nanodroplet properties at extremely low flow rates.