Pentaquadrupole Mass Spectrometer Research Articles

A penta-quadrupole instrument for reaction intermediate scans and other MS-MS-MS experiments

A penta-quadrupole mass spectrometer which utilizes three quadrupole mass filters and two rf-only quadrupole collision cells is described. The instrument allows ion/molecule reactions or collision activated dissociation to be performed in either of the collision regions and is well suited for the acquisition of MS—MS—MS data. The reaction intermediate scan, an MS—MS—MS experiment which interrogates all intermediates which arise from a fixed parent ion and subsequently react to yield a fixed daughter ion, is applied to the examination of peptides, alkyl ketones, and the pyrolysis products of poly(alkylisocyanates). Comparisons are made with reaction intermediate spectra recorded using a sector/quadrupole hybrid instrument. Results from other MS 3 modes, including two-dimensional scans, are presented to illustrate the versatility of the instrument. Access to unique information on ion/molecule chemistry is demonstrated with data on Diels—Alder reactions of 1,3-butadiene.

Observation of sequence‐specific peptide fragmentation using extended tandem mass spectrometry experiments

AbstractReaction‐intermediate spectra are reported for peptide mixtures using a hybrid BEQQ and a pentaquadrupole mass spectrometer. In this extended tandem mass spectrometry scan, the protonated molecule and a terminal fragment ion are selected with the first and third mass analyzers, respectively. A subsequent linked scan at constant B/E (hybrid instrument) or a scan of the middle quadrupole (pentaquadrupole instrument) produces the reaction‐intermediate spectrum. The resulting spectra are simpler than conventional tandem mass spectrometry daughter‐ion spectra and display only sequence ions of one group, viz. A, B and C or X, Y and Z. This information facilitates structural elucidation and is obtainable on nanomole amounts of peptide.