Matrix-Assisted Laser Desorption Ion Trap Mass Spectrometry:  Efficient Trapping and Ejection of Ions

Qin, Jun; Chait, Brian T.

doi:10.1021/ac951162u

Cited by 39 publications

(38 citation statements)

References 19 publications

(39 reference statements)

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“…Using red-shifted off-resonance large-amplitude excitation (RSOR-LAE), Chait and co-workers demonstrated that parent ions can be efficiently fragmented using a single-frequency activation waveform. [30][31][32] This activation method deposits higher amounts of internal energy into the parent ion but at the same time results in less ejection of the parent ion during the activation period. 32 Doroshenko and Cotter also reported an efficient parent ion activation method using "stretched-in-time" SWIFT pulses, which also result in reduced ejection of the precursor ion.…”

Section: Resultsmentioning

confidence: 99%

Narrow-Band Collisional Activation Technique for Ion Trap Mass Spectrometers

1999

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Narrow-bandwidth signals were applied to the end caps of an ion trap mass spectrometer to excite ions during collisional activation. Excitation waveforms were created from a single-frequency component and a random noise component using a multiplier circuit. Tandem and higher order mass spectrometry experiments (MS3) can be performed without optimization of the supplemental frequency applied to the end cap electrodes. The usefulness of this method of ion excitation is demonstrated using singly and multiply protonated peptide ions as well as sodium-cationized carbohydrates.

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Section: Resultsmentioning

confidence: 99%

Narrow-Band Collisional Activation Technique for Ion Trap Mass Spectrometers

1999

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“…The recent commercial introduction of ion-trap mass spectrometers, with their capability for multiple tandem CID experiments (MS 4 and even greater 52,53 ) will facilitate the determination of multiply modified sites on a single peptide.…”

Section: Discussionmentioning

confidence: 99%

Profiling Peptide Adducts of Oxidized N-Acetyldopamine by Electrospray Mass Spectrometry

Kerwin

1997

Rapid Commun. Mass Spectrom.

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Phenolic and catecholamine polymers are common constituents of many biological systems. Cross-linking of polyphenols with other phenols, peptides, proteins and carbohydrates results in the synthesis of complex natural products which are not easily characterized. Electrospray mass spectrometry (ES-MS) and tandem mass spectrometry (ES-MS/MS) were used to identify polymers of oxidized N-acetyldopamine (NADA) and peptide adducts with oxidized NADA. Following incubation with mushroom tyrosinase, NADA adducts of trityrosine were identified. It was not possible to locate the site of NADA binding to this tripeptide. Compounds formed by incubation of N-acetylhistidine and N-acetyllysine with oxidized NADA, previously characterized using classical chemical techniques, were confirmed using ES-MS/MS. The peptide angiotensin (DRVYIHPFHL) was used as a model substrate to determine whether the site(s) to which oxidized NADA bound could be determined. The lot of angiotensin used was contaminated with a peptide of mass 14 u greater than angiotensin, and it was found that the H in position 9 of the contaminant peptide was modified. ES-MS/MS of the angiotensin and the contaminant peptide following incubation with oxidized NADA revealed that the C-terminal aspartic acid was the primary amino acid to which NADA adducts were covalently bound, but other residues were also modified. Femto-molar sensitivity for analysis of complex mixtures of catecholamine-peptide adducts will facilitate structural elucidation of natural products not amenable to characterization using other spectroscopic techniques.

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“…These processes include, but are not limited to, ion injection efficiency, storage efficiency, and detection efficiency. There are few examples known where the necessary experimental steps were taken to measure the true trapping efficiency [12], and none of the previous heavy buffer gas research include these measurements. Therefore, throughout this paper the term sensitivity will be used when discussing comparisons of the ion signal produced with various experimental setups.…”

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The use of static pressures of heavy gases within a quadrupole ion trap

Danell

Glish

et al. 2003

J. Am. Soc. Mass Spectrom.

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The performance of quadrupole ion traps using argon or air as the buffer gas was evaluated and compared to the standard helium only operation. In all cases a pure buffer gas, not mixtures of gases, was investigated. Experiments were performed on a Bruker Esquire ion trap, a Finnigan LCQ, and a Finnigan ITMS for comparison. The heavier gases were found to have some advantages, particularly in the areas of sensitivity and collision-induced dissociation efficiency; however, there is a significant resolution loss due to dissociation and/or scattering of ions. Additionally, the heavier gases were found to affect ion activation and deactivation during MS/MS, influencing the product ion intensities observed. Finally, the specific quadrupole ion trap design and the ion ejection parameters were found to be crucial in the quality of the spectra obtained in the presence of heavy gases. Operation with static pressures of heavy gases can be beneficial under certain design and operating conditions of the quadrupole ion trap. T he quadrupole ion trap mass spectrometer (QITMS) comprises a large and continually growing segment of mass spectrometry. The QITMS possesses many advantages over other mass analyzers, including ease of use, size, cost, and ability to perform MS n analysis. With this greatly increased usage comes the motivation to enhance and extend its abilities. One area that has seen sporadic investigation is the buffer gas used within QITMS. The use and function of the buffer gas has been of interest to researchers for many years prior to commercialization of the QITMS [1][2][3].The buffer gas is an important component of the QITMS and can affect many aspects of its operation. When injecting ions into the QITMS, one function of the buffer gas is to reduce ion kinetic energy. As the ions enter the trapping volume, they will encounter neutral buffer gas atoms or molecules and collide with them. One possible outcome of these collisions is the transfer of kinetic energy from the ions to the neutral target (the buffer gas). This reduction of ion kinetic energy is termed collisional cooling, and the process aids in ion trapping and therefore can improve sensitivity. Many collisions can occur once the ion is nominally trapped, yielding a condensed cloud of ions close to the center of the trapping volume. With all of the ions condensed to the center of the QITMS and possessing similarly low kinetic energies, mass analysis can be performed with higher resolution and sensitivity [3].A collision also can result in ion kinetic energy being converted into ion internal energy. The maximum amount of internal energy that can be deposited into the ion in a single collision is the center-of-mass kinetic energy, E com , and can be calculated using the following eq:where M n is the mass of the neutral buffer gas atom or molecule, M p is the mass of the ion, E lab is the ion's laboratory frame kinetic energy and E com is the centerof-mass kinetic energy. Increasing the internal energy of an ion is the desired outcome when performing coll...

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Matrix-Assisted Laser Desorption Ion Trap Mass Spectrometry: Efficient Trapping and Ejection of Ions

Cited by 39 publications

References 19 publications

Narrow-Band Collisional Activation Technique for Ion Trap Mass Spectrometers

Narrow-Band Collisional Activation Technique for Ion Trap Mass Spectrometers

Profiling Peptide Adducts of Oxidized N-Acetyldopamine by Electrospray Mass Spectrometry

The use of static pressures of heavy gases within a quadrupole ion trap

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