Coupling a quadrupole mass spectrometer and a Fourier transform mass spectrometer

McIver, Robert T.; Hunter, Richard; Bowers, William D.

doi:10.1016/0168-1176(85)85037-0

Cited by 140 publications

(50 citation statements)

References 18 publications

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“…To minimize the associated "magnetic mirror" effect [2] and optimize injection efficiency, ion optics are designed to accelerate and confine ions near the symmetry axis of the solenoidal magnetic field of a high-field superconducting magnet. Radiofrequency (rf) multipole ion guides have been among the most widely adopted ion optics for this purpose [3,4]. Although ion transfer as determined solely by electric fields in multipole ion guides has been thoroughly studied [5][6][7][8], transfer influenced by immersion in a strong magnetic field gradient has not been as well characterized [4,9].…”

Section: Introductionmentioning

confidence: 99%

Excitation of Radial Ion Motion in an rf-Only Multipole Ion Guide Immersed in a Strong Magnetic Field Gradient

Beu¹,

Hendrickson

Marshall

2011

J. Am. Soc. Mass Spectrom.

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Radiofrequency (rf) multipole ion guides are widely used to transfer ions through the strong magnetic field gradient between source and analyzer regions of external source Fourier transform ion cyclotron resonance mass spectrometers. Although ion transfer as determined solely by the electric field in a multipole ion guide has been thoroughly studied, transfer influenced by immersion in a strong magnetic field gradient has not been as well characterized. Recent work has indicated that the added magnetic field can have profound effects on ion transfer, ultimately resulting in loss of ions initially contained within the multipole. Those losses result from radial ejection of ions due to transient cyclotron resonance that occurs when ions traverse a region in which the magnetic field results in an effective cyclotron frequency equal to the multipole rf drive frequency divided by the multipole order (multipole order is equal to one-half the number of poles). In this work, we describe the analytical basis for ion resonance in a rf multipole ion guide with superposed static magnetic field and compare with results of numerical trajectory simulations.

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Section: Introductionmentioning

confidence: 99%

Excitation of Radial Ion Motion in an rf-Only Multipole Ion Guide Immersed in a Strong Magnetic Field Gradient

Beu¹,

Hendrickson

Marshall

2011

J. Am. Soc. Mass Spectrom.

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“…This instrument offers significantly greater mass resolving power and mass measurement accuracy than the quadrupole ion trap, but has the added complexity of a cryogenically cooled magnet and the need to operate at very high vacuum (10 Ϫ8 Pa). Early quadrupole/FT-ICR (Q/FTICR) work was done by the groups of Hunt and McIver [61][62][63]. While this combination of analyzers showed promise, it did not become popular immediately, in part because the magnetic field strengths and data storage capabilities were much more limited at that point in time.…”

Section: Beam-trap Hybrid Instrumentsmentioning

confidence: 99%

Hybrid mass spectrometers for tandem mass spectrometry

Glish

Burinsky

2008

J. Am. Soc. Mass Spectrom.

106

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Mass spectrometers that use different types of analyzers for the first and second stages of mass analysis in tandem mass spectrometry (MS/MS) experiments are often referred to as "hybrid" mass spectrometers. The general goal in the design of a hybrid instrument is to combine different performance characteristics offered by various types of analyzers into one mass spectrometer. These performance characteristics may include mass resolving power, the ion kinetic energy for collision-induced dissociation, and speed of analysis. This paper provides a review of the development of hybrid instruments over the last 30 years for analytical applications. (J Am Soc Mass Spectrom 2008, 19, 161-172) © 2008 American Society for Mass Spectrometry T andem mass spectrometry (MS/MS), in a very generic description, is a process in which an ion formed in an ion source is mass-selected in the first stage of analysis, reacted, and then the charged products from the reaction are analyzed in the second stage of analysis. The type and quality of data that is obtained can vary greatly depending upon the type of analyzer used in the first and second stages of analysis, and the type of reaction performed between the stages of analysis. The reactions that can be done also can depend upon the type of analyzer. Over the years there have been a variety of means developed to measure the mass-to-charge ratio of gas-phase ions. The most common methods involve: dispersion based on ion momentum or kinetic energy (magnetic and electric sector instruments); separation in time based on ion velocity (time-of-flight); transmission through an electrodynamic field (quadrupole mass filter); and periodic motion in a magnetic or electrodynamic field (ion traps). There are differences in the experimental parameters associated with these various analysis methods that are pertinent to the MS/MS experiment. Some parameters are obvious, typically related to the performance of the mass analyzer while others are more subtle, related to the reactions/chemistry occurring between the stages of analysis. Many times these different parameters are used to categorize MS/MS experiments.One parameter is the ion kinetic energy. Sector and time-of-flight (TOF) instruments typically operate at "high" ion kinetic energies (5-20 keV), whereas "low" ion kinetic energies (Ͻ50 eV) are typical in quadrupole mass filters and ion traps. The ion kinetic energy is an important parameter in MS/MS experiments because the most common reaction involves colliding the ion of interest with a target gas atom or molecule. When performing ion-neutral collision experiments, the possible reactions that can be accessed (e.g., collisioninduced dissociation, collisional cooling, charge permutation, ion/molecule reaction) depends upon the ion kinetic energy. The appearance of the MS/MS spectrum can change drastically as a function of the collision (ion kinetic) energy. A related factor that is equally important, but often not considered, is the time frame of the experiment, that is, the elapsed time bet...

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“…The mass spectrometer used in this work is an external ion source Fourier-transform mass spectrometer that was built several years ago at the University of California, Irvine (27)(28)(29)(30)(31)(32). Samples prepared for MALDI analysis are deposited on the tip of a direct probe and inserted into the ion source.…”

Section: Methodsmentioning

confidence: 99%

High-resolution laser desorption mass spectrometry of peptides and small proteins.

McIver

Hunter

1994

Proc. Natl. Acad. Sci. U.S.A.

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Matrix-assisted laser desorption/ionization (MALDI) has been used with an external ion source Fouriertransform mass spectrometer to obtain the highest mass resolution ever, to our knowledge, demonstrated for laserproduced ions (r/Am = 1,100,000 for [Arg8Jvasopressin, 228,000 for melittin, and 90,000 for bovine insulin). The peaks in the isotope cluster for bovine insulin are fully resolved, and the mass measurement accuracy is an order of magnitude better than can be achieved with time-of-flight mass spectrometry. With the method described here, analyte is applied to a sample probe and mixed with a solution containing a matrix material (2,5-dihydroxybenzoic acid) that strongly absorbs ultraviolet light. Upon irradiation with a pulse from an excimer laser (353 nm, 2 mJ), a large number of intact protonated molecular ions are produced. The ions are focused by a 117-cm-long quadrupole ion guide and injected into an ion cyclotron resonance analyzer cell located inside the bore of a 6.5-T superconducting magnet. A pulse of argon buffer gas cools the ions prior to detection. One of the principal advantages of an external ion source Fourier-transform mass spectrometer is that the ion formation and ion detection processes are separated and can be independently optimized.In 1988, Karas and Hillenkamp introduced a mass spectrometry method called matrix-assisted laser desorption/ionization (MALDI) for measuring the molecular weights ofbiopolymers (1-3). The key idea is to isolate and surround analyte biomolecules with a matrix material that strongly absorbs laser light.When an incident laser pulse strikes the solid matrix/ biomolecule mixture, ablation and ionization of the surface layer occurs very rapidly. One might expect that fragile biomolecules would not survive such a violent event, but, remarkably, they remain intact and appear as the main peaks in a mass spectrum. Selection of an appropriate matrix material has proven to be critical to the success of MALDI. Beavis and Chait screened hundreds of possible matrices and found that cinnamic acid derivatives are excellent for the analysis of peptides and proteins (4,5). With the introduction a few years ago ofinexpensive MALDI mass spectrometers, the technique has become an essential tool in many protein biochemistry laboratories (6, 7).Most MALDI applications use time-of-flight mass spectrometry (TOF-MS) to mass analyze and detect the laserproduced ions. Although this method is rapid and has picomolar sensitivity, the mass measurement accuracy is somewhat limited. Several processes that limit the mass resolution and mass measurement accuracy ofTOF mass spectrometers have been identified (8). One cause of peak broadening is the considerable energy spread of the ions. Even at the threshold for ionization, the energy spread can be as large as 30 eV, and as the laser power is increased the spread increases further (9-11). This causes there to be a distribution of arrival times and a broadening of the peaks in the TOF mass spectrum. Further peak broadening can occur...

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Coupling a quadrupole mass spectrometer and a Fourier transform mass spectrometer

Cited by 140 publications

References 18 publications

Excitation of Radial Ion Motion in an rf-Only Multipole Ion Guide Immersed in a Strong Magnetic Field Gradient

Excitation of Radial Ion Motion in an rf-Only Multipole Ion Guide Immersed in a Strong Magnetic Field Gradient

Hybrid mass spectrometers for tandem mass spectrometry

High-resolution laser desorption mass spectrometry of peptides and small proteins.

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