Laser desorption from a probe in the cavity of a quadrupole ion storage mass spectrometer

Heller, David; Lys, Ihor; Cotter, Robert J.; Uy, O. Manuel

doi:10.1021/ac00185a008

Cited by 47 publications

(15 citation statements)

References 13 publications

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“…Laser desorption has been used to perform internal and external ionization in these devices. [1][2][3][4][5] Photodissociation has been used to deposit high internal energies into trapped ion clouds of biomolecules, 6 to acquire spectroscopic information [7][8][9] and to probe the spatial and temporal distributions of the ion cloud. [10][11][12] In addition, resonanceenhanced multiphoton ionization (REMPI) has been used to investigate fragmentation mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Selective Photodissociation of Trapped Ions after Ion Cloud Manipulation with an Impulsive Quadrupolar Electric Field

Cleven¹,

Nappi²,

Cooks³

et al. 1996

J. Phys. Chem.

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Trapped ions of different masses can be separated in space within a quadrupole ion trap, making it possible to perform efficient mass-selective photodissociation on a mixture of ions. This method employs an axial quadrupolar dc pulse (1 µs) to force all ions into coherent radial motion; ions of the same mass-to-charge ratio are either in phase or phase-shifted by exactly 180°. After this activating pulse, the ions continue to oscillate at their secular frequency in a coherent fashion so that ions of the same mass-to-charge ratio simultaneously cross the z-axis (r ) 0) twice per secular cycle. At this specific moment, a single-pulse (15 ns) laser beam, aligned collinear with the z-axis, can be used to improve the photodissociation efficiency by irradiating these ions that are radially focused along the z-axis and within the confines of the laser beam. The length of the delay time between the dc pulse and the laser pulse is critical, as it controls the phase, and hence the spatial position, of the ions when the laser is fired. Under the given operating conditions, this method improves the photodissociation efficiency from 9% to 35%. The photodissociation efficiency steadily decreases with longer delay times as the oscillating ions undergo increasing numbers of collisions with the helium buffer gas and lose coherence. Since the secular frequencies of trapped ions are mass-dependent at a fixed rf amplitude, ions of different mass-to-charge ratios will cross the z-axis at different times. Massselective photodissociation is illustrated for a mixture of benzoyl-h 5 and -d 5 cations by appropriately adjusting the delay time between the dc pulse and the laser pulse. Simulations using the program ITSIM were used to design this experiment, and the data which describe the ion motion are provided.

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Section: Introductionmentioning

confidence: 99%

Selective Photodissociation of Trapped Ions after Ion Cloud Manipulation with an Impulsive Quadrupolar Electric Field

Cleven¹,

Nappi²,

Cooks³

et al. 1996

J. Phys. Chem.

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“…The efficacy of the interface by which ions generated externally are admitted to an ion trap and confined therein depends upon both the efficiency and mass dependence of ion trapping. Methods for injecting ions created externally have been developed for laser desorption ionization, [19][20][21] a Cs secondary ion mass spectrometric (SIMS) source, 22 an atmospheric sampling glow discharge ionization source, 23,24 electrospray ionization (ESI), 25,26 ion spray (pneumatically assisted electrospray) ionization 27 and matrix-assisted laser desorption/ionization (MALDI). [28][29][30][31][32] The three principal approaches to the introduction of externally generated ions to an ion trap are (i) injection through an end-cap electrode or desorption near its internal surface (axial injection), (ii) injection through the ring electrode or desorption near its internal surface (radial injection), and (iii) injection along an asymptote (asymptotic injection).…”

Section: Injection and Storage Of Ions Generated Externallymentioning

confidence: 99%

Quadrupole ion trap mass spectrometry: theory, simulation, recent developments and applications

March

1998

Rapid Commun. Mass Spectrom.

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This paper is a presentation of recent key developments in quadrupole ion trap mass spectrometry. These key developments have been made in three areas; namely, the trapping of ions generated externally to the ion trap, the fine control of the trajectories of ions confined within the ion trap, and the ejection of ions from the ion trap. Applications of quadrupole ion trap mass spectrometry that are illustrative of these developments are discussed. The origin of the quadrupole ion trap and its mode of current usage are discussed briefly. # 1998 John Wiley & Sons, Ltd. Received 20 June 1998; Revised 7 August 1998; Accepted 9 August 1998 The original commercial usage of a quadrupole ion trap was limited to the formation of ions in situ by electron impact ionization, focusing of the nascent ions to a cloud at the centre of the ion trap, and mass-selective axial ejection of ions to form a mass spectrum. The sheer simplicity of the mass-selective axial ejection technique permitted the commercialization of the quadrupole ion trap as a massselective detector for compounds separated by gas chromatography. In the past 15 years, the field of quadrupole ion trap mass spectrometry has developed appreciably; while it is not possible to consider all developments, attention can be focused on the key developments that extend or enhance ion trap performance markedly. The key instrumental developments cover three main areas: (a) the injection and storage of ions generated externally to the ion trap; (b) the fine control of the trajectories of ions confined within the ion trap; (c) the ejection of ions from the ion trap.

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“…CO 2 gas lasers have been used in the past for a variety of applications in materials analysis and processing. They have, for example, been employed successfully for laser desorption of small biological molecules without a matrix in conjunction with sector 19 and quadrupole 20 mass spectrometers, as well as time-of-flight (TOF) 21,22 and Fourier transform ion cyclotron resonance (FTICR) 23,24 analyzers. This paper reports results for the IR-MALDI-MS with a sealed-off TEA-CO 2 laser, comparable in complexity and price to N 2 lasers commonly used in UV-MALDI-MS.…”

mentioning

confidence: 99%

Infrared matrix-assisted laser desorption/ionization mass spectrometry with a transversely excited atmospheric pressure carbon dioxide laser at 10.6 µm wavelength with static and delayed ion extraction

Menzel

Berkenkamp

Hillenkamp

1999

Rapid Commun. Mass Spectrom.

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Received 9 September 1998; Revised 3 November 1998; Accepted 4 November 1998Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) 1 has become a well-established method in the analysis of large macromolecular compounds over the last decade. The most widely used lasers for matrixassisted desorption/ionization (MALDI) emit in the ultraviolet (UV) at wavelengths in the range from 260 to 360 nm. Energy deposition in this wavelength range is based on the strong electronic absorption of the aromatic matrix compounds.As early as 1990 the first results of MALDI-MS with infrared (IR) lasers were published.2 So far IR wavelengths in the 3 mm range have almost exclusively been used for IR-MALDI-MS. Either solid state erbium lasers like the erbium-yttrium aluminum garnet (Er:YAG) (! = 2.94 mm) or erbium-yttrium-scandium-gallium garnet (Er:YSGG) (! = 2.79 mm) laser 2,3 have been employed and, more recently, tunable midinfrared optical parametric oscillators (OPO). [4][5][6][7] Energy deposition at 3 mm results from a vibrational excitation of O-H and N-H stretching modes. Only a few reports so far have dealt with IR-MALDI in other IR wavelength regions. With a free-electron laser (FEL) mass spectra in the 5.5-6.5 mm wavelength range have been obtained, making use of the C=O absorption band.8

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Laser desorption from a probe in the cavity of a quadrupole ion storage mass spectrometer

Cited by 47 publications

References 13 publications

Selective Photodissociation of Trapped Ions after Ion Cloud Manipulation with an Impulsive Quadrupolar Electric Field

Selective Photodissociation of Trapped Ions after Ion Cloud Manipulation with an Impulsive Quadrupolar Electric Field

Quadrupole ion trap mass spectrometry: theory, simulation, recent developments and applications

Infrared matrix-assisted laser desorption/ionization mass spectrometry with a transversely excited atmospheric pressure carbon dioxide laser at 10.6 µm wavelength with static and delayed ion extraction

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