Achieving 50% ionization efficiency in subambient pressure ionization with nanoelectrospray

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Ionization Techniques

Background:

• Electrospray ionization is crucial for mass spectrometry but suffers from low ion transmission efficiency.
• Inefficient transfer of charged species from ambient pressure to high vacuum limits sensitivity in mass analysis.

Purpose of the Study:

• To introduce and evaluate a new electrospray-based ion source designed for improved ion transmission.
• To enhance the sensitivity of mass spectrometry by optimizing ion delivery from the source to the vacuum region.

Main Methods:

• Development of a new electrospray ion source operating at approximately 20 Torr.
• Operation at controlled flow rates of 50 nL/min to facilitate ion transfer.
• Tuning the ion source to optimize analyte signal and minimize background noise.

Main Results:

• The new ion source delivers approximately 50% of analyte ions from solution into the rough vacuum region.
• Efficient transmission of charged, desolvated species was observed.
• The source demonstrated tunability for optimizing signals of readily ionized species.

Conclusions:

• The developed electrospray ion source significantly enhances ion transmission efficiency for mass spectrometry.
• This advancement offers a pathway to higher sensitivity in analytical measurements.
• The tunable nature of the source allows for optimization across various analytes.