Infoscience

Journal article

Electron capture dissociation fourier transform ion cyclotron resonance mass spectrometry in the electron energy range 0-50 eV

Electron capture dissocn. (ECD) of polypeptide cations was obtained with pencil and hollow electron beams for both sidekick and gas-assisted dynamic ion trapping (GADT) using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) with an electrostatic ion transfer line. Increasing the no. of trapped ions by multiple ICR trap loads using GADT improved the ECD sensitivity in comparison with sidekick ion trapping and ECD efficiency in comparison with single ion trap load by GADT. Furthermore, enhanced sensitivity made it possible to observe ECD in a wide range of electron energies (0-50 eV). The degree, rate and fragmentation characteristics of ECD FTICR-MS were investigated as functions of electron energy, electron irradn. time, electron flux and ion trapping parameters for this broad energy range. The results obtained show that the rate of ECD is higher for more energetic (>1 eV) electrons. Long electron irradn. time with energetic electrons reduces av. fragment ion mass and decreases efficiency of formation of c- and z-type ions. The obtained dependencies suggest that the av. fragment ion mass and the ECD efficiency are functions of the total fluence of the electron beam (electron energy multiplied by irradn. time). The measured electron energy distributions in low-energy ECD and hot ECD regimes are about 1 eV at full width half max. in employed exptl. configurations. [on SciFinder (R)]

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