Fabricating an Electrospray Ionization Chip Based on Induced Polarization and Liquid Splitting

Area of Science:

• Analytical Chemistry
• Microfluidics
• Mass Spectrometry

Background:

• Microfluidic chip-mass spectrometry (MS) coupling is vital for chemical and biological analysis.
• Electrospray ionization (ESI) is the primary ionization technique for chip-MS systems.
• Conventional chip-based ESI relies on direct electrical contact, limiting its capabilities.

Purpose of the Study:

• To develop a novel microchip ESI source utilizing a polarization-splitting approach.
• To enable simultaneous generation of positive and negative ions from a single microfluidic chip.
• To advance chip-based ESI for enhanced mass spectrometry analysis.

Main Methods:

• A microchip ESI source was designed based on a polarization-splitting technique.
• Droplets within a microchannel were polarized by an electric field, inducing splitting into two charged sub-droplets.
• The charged droplets were directed to an emitter to initiate the electrospray process.

Main Results:

• The polarization-splitting ESI (PS-ESI) chip successfully generated charged droplets with opposite polarities.
• Both positive and negative ions were formed from the same solution.
• Preliminary experiments demonstrated the feasibility of coupling the PS-ESI chip with MS for analyte analysis.

Conclusions:

• The novel PS-ESI chip offers a new method for generating both polarities of ions simultaneously.
• This approach eliminates the need for direct electrical contact, simplifying chip design.
• The developed chip-MS system facilitates conventional ESI-MS analysis of diverse analytes.