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Rephasing ion packets in the Orbitrap mass analyzer to improve resolution and peak shape
Richard H Perry1, Qizhi Hu, Gary A Salazar
1Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA.
Journal of the American Society for Mass Spectrometry
|March 21, 2009
Summary
A novel rephasing method enhances Orbitrap mass spectrometry resolution by up to threefold. This technique improves peak shape and may enable advanced tandem mass spectrometry (MS/MS) applications.
Area of Science:
- Analytical Chemistry
- Mass Spectrometry
- Physical Chemistry
Background:
- Orbitrap mass analyzers are known for high mass accuracy and resolution.
- Specific experimental conditions can lead to degraded peak shape and resolution.
- Improving ion packet characteristics is crucial for advanced mass spectrometry techniques.
Purpose of the Study:
- To develop and demonstrate a method for enhancing resolution and peak shape in Orbitrap mass spectrometry.
- To investigate the effect of an AC waveform on ion packets under anharmonic axial potentials.
- To assess the potential for improved tandem mass spectrometry (MS/MS) performance.
Main Methods:
- Inducing an asymmetric anharmonic axial potential in the Orbitrap by detuning a compensator electrode voltage.
- Applying a resonant AC waveform to the outer electrode, 180 degrees out of phase with ion motion.
- Utilizing the 'rephasing' phenomenon to narrow ion axial spatial extent and frequency distribution.
Main Results:
- Achieved a 2- to 3-fold improvement in resolution, reaching 124,000 to 171,000.
- Demonstrated significant enhancement in peak shape compared to standard conditions.
- Observed improved performance at a reserpine concentration of 10 ng/µL.
Conclusions:
- The described rephasing method effectively improves Orbitrap resolution and peak shape.
- This technique offers a pathway to implement high-performance MS/MS directly within the Orbitrap.
- Potential for leveraging Orbitrap's capabilities for both precursor and product ion analysis in MS/MS.
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