Interface for a four-sector mass spectrometer with a dual-purpose collision cell: High transmission at low to intermediate energies

Abstract

A new interface system that consists of an ion decelerator, a floating collision cell-chemical ionization ion source, and an ion extractor was designed and installed in the third field-free region of a four-sector tandem mass spectrometer. Important features include the use of cylindrical deceleration lenses and an extraction lens assembly. This new design was found to provide enhancement of ion transmission at low to intermediate ion kinetic energies (3 eV to 1 keV) compared with the standard collision cell design. Collision-induced dissociation experiments from 3 eV to 10 keV and ion-molecule reactions of mass-selected ions can be performed conveniently. A second, grounded, collision cell is located after the extraction lenses, which allows MS(4) experiments to be carried out via the normal linked (B/E) scan function in MS2. Incorporation of chemical ionization capability into the electrically isolated collision cell makes it possible to carry out neutralization chemical-reionization mass spectrometry.

Energetics and Dynamics of Fragmentation of Protonated Leucine Enkephalin from Time- and Energy-Resolved Surface-Induced Dissociation Studies

“…Figure shows representative SID spectra of YGGFL for 30 and 50 eV collisions with the HSAM surface and reaction delay of 1 s. SID spectra shown in Figure are similar to MS/MS spectra of leucine enkephalin reported in the literature. − At low collision energies, fragmentation is dominated by the formation of the b 4 / a 4 ion pair and loss of water from the protonated precursor ion resulting in formation of the b 5 ion. SID spectrum obtained at 50 eV collision energy contains a large number of sequence specific fragments including an almost complete series of b n ions ( b 2 − b 5 ) and y n ions ( y 1 − y 3 ), a number of a n and a n -NH 3 ions ( a 5 , a 5 *, a 4 , a 4 *), a series of internal fragments (GGF, GGF−CO, GF, GF−CO), and immonium ions (F, Y).…”

“…Figure 1 shows representative SID spectra of YGGFL for 30 and 50 eV collisions with the HSAM surface and reaction delay of 1 s. SID spectra shown in Figure 1 are similar to MS/MS spectra of leucine enkephalin reported in the literature. [14][15][16][17][18][19][20][21][22][23][24][25][26] At low collision energies, fragmentation is dominated by the p(E, Dissociation Pathways. Detailed modeling of dissociation of protonated leucine enkephalin and the energetics and kinetics of formation of its fragments requires knowledge of dissociation pathways following ion activation.…”

“…Dissociation of protonated leucine enkephalin (YGGFL) in the gas phase has been extensively studied using a variety of experimental approaches. − Both BIRD and ion trap collision-induced dissociation (CID) experiments were utilized to study thermal kinetics of dissociation of YGGFL. , A relatively simple dissociation pattern and well-established thermal kinetics make YGGFL an excellent “thermometer” ion for characterization of internal energy deposition into peptide ions in different ionization and activation processes. − …”

The structure and fragmentation of Bn (n≥3) ions in peptide spectra

“…In the present work we have extended these calculations to the larger B from penta-alanine and from Leu-enkephalin by loss of (CO + NH 3 ) also is observed. Reaction 2 also is observed in the fragmentation of B 2 ions [7]; however, reaction 3, which has been observed earlier [17,18] for larger B ions, is not observed for B 2 ions. Tables 2 and 3 also report the kinetic energy releases (T I / 2 ) measured, where possible, for fragmentation reactions 2 and 3 that occur on the metastable ion time scale.…”

High-energy electron transfer dissociation (HE-ETD) using alkali metal targets for sequence analysis of post-translational peptides

“…Although several small and broad peaks are observed in both m/z regions lower and higher than that of the precursor ions, series of peaks ascribable to backbone cleavage of the peptide sequence are not observed. While CAD spectra using 4-sector MS/MS instruments reported by Biemann and Martin [47] and Fenselau and coworkers [48] provided sharp peaks assigned as a-type ions, our spectrum using 3-sector (EBE) instrument provided broad peaks due to kinetic energy releases. On the other hand, as seen in Figure 2b, when the Cs target is employed, many sharp peaks are observed in m/z regions both lower and higher than that of the precursor ions, accompanied by the ions observed in the CID spectra measured with the Xe target.…”