Improving ion mobility measurement sensitivity by utilizing helium in an ion funnel trap

Area of Science:

• Analytical Chemistry
• Physical Chemistry

Background:

• Ion mobility spectrometry (IMS) commonly uses nitrogen as a buffer gas in ion traps and drift cells.
• Previous assumptions suggested inert gases have minimal impact on IMS performance for larger ions.

Purpose of the Study:

• To investigate the effect of adding helium to an ion funnel trap and drift cell in IMS.
• To evaluate the impact of helium on signal intensity and resolving power in IMS.

Main Methods:

• Utilized an ion funnel trap preceding an ion mobility spectrometer.
• Introduced helium-nitrogen (He/N2) gas mixtures into the ion funnel trap and drift cell.
• Compared performance metrics (signal intensity, resolving power) against nitrogen-only systems.

Main Results:

• Observed over an order of magnitude improvement in signal intensity for higher m/z species with helium addition.
• Reported a slight improvement in IMS resolving power when using He/N2 mixtures in the drift cell.
• Attributed signal enhancement to faster and more efficient ion ejection from the ion funnel trap.

Conclusions:

• Helium addition to ion funnel traps offers significant performance benefits for IMS, particularly for larger ions.
• The use of helium can enhance ion ejection efficiency, leading to improved signal intensity.
• Further investigation into helium's role in IMS may reveal additional performance optimizations.