Large Molecule Characterization Based upon Individual Ion Detection with Electrospray Ionization-FTICR Mass...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Biophysics

Background:

• Conventional Fourier transform ion cyclotron resonance (FTICR) mass spectrometry faces limitations in resolving power and precision for high-molecular-weight species.
• Coulombic constraints and FTICR cell charge capacity restrict accurate mass measurements for molecules exceeding approximately 80 kDa.
• Degradation in FTICR performance occurs due to frequency shifts and peak coalescence when ion populations approach or exceed cell capacity.

Purpose of the Study:

• To introduce a novel method for mass spectrometric analysis of high-molecular-weight species.
• To overcome the inherent limitations of conventional FTICR mass spectrometry for large multiply charged molecules.
• To achieve enhanced resolution and mass measurement accuracy for very large molecules.

Main Methods:

• The new method involves the summation of sequential FTICR spectra from individual multiply charged ions.
• This approach relies on high sensitivity for detecting individual ions.
• Data processing and summation are employed to suppress noise and enhance signal for statistically relevant spectra.

Main Results:

• The developed method produces statistically useful mass spectra for large multiply charged molecular species.
• It circumvents conventional limitations imposed by Coulombic constraints and FTICR cell charge capacity.
• Demonstration on bovine serum albumin (66 kDa) shows potential for improved resolution and mass accuracy.

Conclusions:

• The summation of sequential FTICR spectra offers a viable approach for analyzing high-molecular-weight species.
• This method significantly enhances mass measurement accuracy and resolution beyond conventional capabilities.
• It provides a foundation for more precise characterization of very large molecules in mass spectrometry.