A reliable and simple method for fabricating a poly(dimethylsiloxane) electrospray ionization chip with a...

Area of Science:

• Analytical Chemistry
• Microfluidics
• Mass Spectrometry

Background:

• Monolithically integrated emitters are crucial for microfluidic devices coupled to mass spectrometers (MS) as electrospray ionization (ESI) sources.
• Existing methods for emitter integration can be complex and limit reproducibility.

Purpose of the Study:

• To develop a novel, duplicable method for fabricating microfluidic chips with integrated emitters for ESI-MS.
• To enhance the stability, reliability, and reproducibility of ESI-MS performance using the new chip design.

Main Methods:

• Fabrication of a poly(dimethylsiloxane) (PDMS) chip integrating an emitter into a chip corner.
• Utilized two photoresist layers with a raised base for precise emitter tip integration and protection during prototyping.
• Evaluated ESI-MS performance and compared it with a commercial fused-silica capillary source.

Main Results:

• Achieved highly stable ESI-MS performance with the integrated emitter chip.
• Demonstrated excellent chip-to-chip and run-to-run reliability and reproducibility in fabrication.
• The developed chip showed comparable or superior performance to commercial ESI sources.

Conclusions:

• The proposed microfluidic chip with an integrated emitter offers an ideal ion source for mass spectrometry applications.
• The fabrication method is duplicable, reliable, and reproducible, facilitating widespread use.
• This technology is particularly promising for portable MS systems enabling on-site analysis.