Protein Analysis by Electrospray-Orbital Frequency Analyzer with Charge Detection Mass Spectrometry Algorithm.

Orbital frequency analyzer (OFA) is one of the electrostatic ion trap mass analysers for FTMS, which offers ultrahigh mass resolution and high ion charge capacity. In order to analyze multiply charged proteins and other large biological particles by means of charge detection mass spectrometry, a data processing algorithm was created to suit the image charge signal of nonharmonic waveform nature. The algorithm is capable of detecting collisions between ions and residual gas molecules, to determine lifetime of ions, and to evaluate the charge and mass values for ions having lifetime above a threshold.

High-Capacity Electrostatic Ion Trap with Mass Resolving Power Boosted by High-Order Harmonics.

A form of electrostatic ion trap mass analyzer, named the orbital frequency analyzer (OFA), has been developed. The ions in the analyzer are trapped around the middle plane and orbit around the central axis perpendicular to the middle plane with high-ellipticity and precessing trajectories. The orbital frequency of the ions in this device has been optimized to be independent of ions' energy so that the image charge signal picked up by some of the field-forming circular/ring electrodes can be used to produce a mass spectrum after Fourier transform data processing.