Extracting biomolecule collision cross sections from FT-ICR mass spectral line shape

Area of Science:

• Analytical Chemistry
• Physical Chemistry
• Spectroscopy

Background:

• Fourier transform mass spectrometry (FT-MS) is crucial for ion structure analysis.
• Extracting ion collision cross sections (CCS) from FT-MS data requires robust methods.
• Existing time-domain and frequency-domain methods have limitations in accuracy and consistency.

Purpose of the Study:

• To introduce a novel frequency-domain method for calculating ion CCS from FT-MS data.
• To evaluate the performance of the new line shape fitting method using simulated and experimental data.
• To compare the line shape fitting method with existing techniques, such as the linewidth correction method.

Main Methods:

• Development of a new frequency-domain line shape fitting method for CCS calculation.
• Utilized simulated FT-ICR mass spectrometry data with controlled signal-to-noise ratios and decay factors.
• Applied the method to experimental FT-ICR mass spectra of peptides and proteins (angiotensin I, bradykinin, ubiquitin, cytochrome c).

Main Results:

• The line shape fitting method demonstrates greater tolerance to noise, data length, and sampling rate compared to the linewidth correction method.
• The new method provides more consistent CCS measurements.
• Improved resolving power was observed in CCS measurements of tested biomolecules.

Conclusions:

• The line shape fitting method is a more robust and accurate approach for determining ion CCS in FT-MS.
• This advancement enhances the capability of FT-MS for detailed ion structure analysis.
• The method offers improved performance for analyzing complex biological molecules.