Evaluation of pulsed fast-atom bombardment ionization for increased sensitivity of tandem mass spectrometry

Detection of femtomole and sub-femtomole levels of peptides by tandem magnetic sector/reflectron time-of-flight mass spectrometry and matrix-assisted laser desorption ionization

“…Because the yield of intact molecular ions (typically [M + H]+) is high/ matrix-assisted laser desorption [3] could potentially impact structural mass spectrometry, but such experiments are limited by current instrument technology. For example, tandem mass spectrometry is not a routine experiment for time-of-flight [4] or other pulsed instruments, and pulsed ionization methods are not generally compatible with conventional analytical tandem mass spectrometers (magnetic sector or quadrupole instruments) [5). In terms of the mass resolution required for selection of the analyte ion by MSI, high-performance magnetic sector instruments are advantageous for studies of complex biomolecules.…”

An evaluation of the analytical utility of the photodissociation of fast ion beams

“…We have proposed a new approach to overcoming such limitations, specifically the use of pulsed fast atom bombardment (FAB) ionization. * Pulsing the FAB gun results in neutral beam densities (100-150 FA) much greater than those obtainable for continuous FAB ionization (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) (9).…”

“…Other novel features of the proposed photodissociation apparatus include a pulsed Cs+ ion liquid SIMS ion source and a high peak power (10-200 mJ) high repetition rate (80-150 Hz) pulsed excimer laser system. A major limitation with the photodissociation of large ions (m/z > 500) is that the efficiencies for producing fragment ions is low, (typically less 1 ion in 10,000 photodissociate) (9). Although the photon absorption cross-sections for large biomolecules are large, the photon energy is randomized into a large number of degrees of freedom, thereby reducing the rate of dissociation.…”

Liquid matrices for liquid secondary ion mass spectrometry–fast atom bombardment: An update

“…An estimation of the gain in sensitivity was two orders of magnitude, as described in Fig. 1 (20). Pulsed sources are ideally suited for obtaining high-sensitivity spectra with time-of-flight (21) or Fourier transform mass spectrometers (22).…”