Polymer microspray with an integrated thick-film microelectrode.

Area of Science:

• Analytical Chemistry
• Microfabrication
• Mass Spectrometry

Background:

• Traditional electrospray ionization (ESI) interfaces often require complex setups and can suffer from instability.
• Developing robust and efficient microscale ESI sources is crucial for advancing portable and high-throughput mass spectrometry.

Purpose of the Study:

• To develop and characterize a novel sheathless electrospray interface fabricated using microfabrication techniques.
• To evaluate the performance of the device as an ionization source for mass spectrometry analysis of proteins and small molecules.

Main Methods:

• Microfabrication of a polymer substrate using photoablation to create a sealed microchannel with an integrated thick-film conductive track.
• Embedding a microelectrode for high voltage supply near the spray outlet.
• Direct generation of microspray from the substrate edge without external emitters.
• Performance evaluation using simple infusion of proteins and reserpine for mass spectrometry analysis.

Main Results:

• Demonstrated a stable and efficient ionization source with a sheathless electrospray interface.
• Achieved a stable mass spectrometry (MS) signal over time, with the device being reusable without failure.
• Determined a picomolar detection limit for reserpine in full-scan MS mode, consuming approximately 500 zmol.
• Established a wide dynamic range from picomolar to millimolar levels.

Conclusions:

• The developed microfabricated sheathless electrospray interface is a highly efficient and stable ionization source for mass spectrometry.
• The technology offers flexibility in design and demonstrates excellent performance for analyzing diverse analytes, including proteins and small molecules.
• This advancement facilitates sensitive and robust MS analyses with potential for miniaturized and field-deployable systems.