Improved Methods for Recording Accurate Collision Cross Sections Using Cyclic Ion Mobility-Mass Spectrometry

Area of Science:

• Analytical Chemistry
• Biophysical Chemistry
• Separation Science

Background:

• Traveling wave ion mobility (TWIM) is a gas-phase separation technique for analyzing protein structures and complex mixtures.
• Collision cross section (CCS) values provide analyte size information but require calibration.
• Existing TWIM calibration methods have limitations, especially for advanced cyclic ion mobility (cIM) applications.

Purpose of the Study:

• To develop and validate a comprehensive method for accurate cIM calibrations using blend and radial expressions.
• To optimize cIM calibration for multipass and IMS^n modes of operation.
• To reduce CCS measurement error in cIM analyses.

Main Methods:

• Applied blend and radial expressions for cIM calibration.
• Corrected ion arrival times for time spent outside the separator.
• Minimized velocity relaxation effects during separation.
• Developed an optimized workflow for multipass and IMS^n cIM modes.

Main Results:

• Achieved accurate cIM calibrations using blend and radial expressions.
• Reduced CCS measurement error through arrival time corrections and minimized velocity relaxation.
• Demonstrated the applicability of the method across various cIM operational modes.

Conclusions:

• The developed method provides accurate and reliable CCS measurements for cIM.
• This approach enhances the capabilities of cIM for structural biology and complex mixture analysis.
• Optimized calibration workflows are crucial for advancing cIM applications in IMS^n and multipass separations.