The Mass Filter: Design and Performance

Austin, W.E.; Holme, A.E.; Leck, J.H.

doi:10.1016/b978-0-444-41345-1.50011-3

Cited by 27 publications

(32 citation statements)

References 20 publications

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“…For a larger laser bandwidth, ll.mL = 0.74cm-1 , the effect of laser detuning cannot be discerned within the experimental precision (Table 1 ( 2)). The slight change in the value of (1 + cx) suggesting that the lower velocities of the heavier isotopes make them more susceptible to fringing fields [30].…”

Section: Wavelength Dependencementioning

confidence: 99%

“…57 (8) 51 (12) -1.3(13) 5.7 (13) 89 (10) 65 (18) 36(8) 32 (8) and on the geometry of the ion extraction field [30], particularly if ions are extracted preferentially from regions with lower laser intensity. This condition can produce changes in isotope ratios without inducing significant variations in the total photoion signal.…”

Section: Selection Rule and Polarization Effectsmentioning

confidence: 99%

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Laser-induced isotopic selectivity in the resonance ionization of Os

Wunderlich

Hutcheon

Wasserburg

et al. 1992

International Journal of Mass Spectrometry and Ion Processes

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Isotope selective effects in resonance ionization mass spectrometry (RIMS) pose a potentially serious limitation to the application of this technique to the precise and reproducible measurement of isotope ratios. In order to identify some of the underlying causes of isotope selectivity in RIMS and to establish procedures for minimizing these effects, we investigated laser-induced isotope selectivity in the resonance ionization of Os. A single-color, one-photon resonant ionization scheme was used for several different transitions to produce Os photoions from a thermal atomization source. Variations in Os isotope ratios were studied as a function of laser parameters such as wavelength, bandwidth, power and polarization state. Isotope selectivity is strongly dependent on laser power and wavelength, even when the bandwidth of the laser radiation is much larger than the optical isotope shift. Variations in the 190 0s/ 188 0s ratio of ~ 20% for a detuning of 0.8 em_, were observed on a transition with a small oscillator strength. Large even-odd isotope selectivity with a 13% depletion of 189 0s was observed on a !'J.J = +I transition at low laser intensity; the odd mass Os isotopes are systematically depleted. For !'J.J = -I and 0 transitions the isotope selectivity was reduced by polarization scrambling and for strongly saturating conditions. A technique employing the wavelength dependence of even-even isotope selectivity as an internal wavelength standard was developed to permit accurate and reproducible wavelength adjustment of the laser radiation. This technique provides control over laser-induced isotope selectivity for single-color ionization and enabled us to obtain reproducible measurements of 192 0s/ 188 0s and 189 0s/ 190 0s ratios in the saturation regime for a !'J.J = +I transition with a precision of better than 0.5%. The application of this wavelengthtuning procedure should significantly improve the quality of RIMS isotope ratio data for many elements.

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Section: Wavelength Dependencementioning

confidence: 99%

Section: Selection Rule and Polarization Effectsmentioning

confidence: 99%

Laser-induced isotopic selectivity in the resonance ionization of Os

Wunderlich

Hutcheon

Wasserburg

et al. 1992

International Journal of Mass Spectrometry and Ion Processes

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“…If the quadrupole mass filter was operating at 80 kHz, the unslowed ions would experience 60 cycles of the trap. According to Dawson [10], the limiting resolution is defined by:…”

Section: Resultsmentioning

confidence: 99%

“…This design uses a circularly concave electrode structure to minimize the cross section of the device while maximizing the radius. The concept of using this structure was first demonstrated by Hayashi and Sakudo [11] and later illustrated in Dawson's text [10]. This configuration was used to create a large-radius linear quadrupole ion trap (LR-LQIT).…”

Section: Methodsmentioning

confidence: 99%

“…This quadrupole was operated as a mass filter by varying the duty cycle of the square waveform [9]. The duty cycle was varied from 0.5 to 0.4 to obtain the best resolution while maintaining sufficient throughput to clearly observe a spectrum [10]. The low voltage waveforms were generated with a digital to analog converter (DAC) (National Instruments, Austin, TX, USA, PCI-6120).…”

Section: Methodsmentioning

confidence: 99%

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Controlling the expansion into vacuum—the enabling technology for trapping atmosphere-sampled particulate ions

Koizumi¹,

Wang

Whitten³

et al. 2010

J. Am. Soc. Mass Spectrom.

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A new inlet has been designed to control the kinetic energy distributions of ions into a large-radius, frequency-adjusted, linear quadrupole ion trap. The work presented here demonstrates trapping singly-charged, intact proteins in the 10 to 200 kDa range injected from the atmosphere. The trapped ions were held while collisions with a buffer gas removed the remaining amounts of expansion-induced kinetic energy. The ions were then ejected from the trap on-demand into an awaiting detector. There is no low mass limit for ion injection and trapping. The upper limit presented in this study was defined by the limit of the conversion dynode-based detector at ϳ1.5 MDa. Trapping larger masses should be achievable. The transmission and capture efficiency across the entire mass range should be very high because the entire flow from the inlet empties directly into the trap. The kinetic energy distribution of massive ions is the primary reason for the working range limitation of mass spectrometers. Trapping ions with collisional cooling before mass analysis permits the motion of the ions to be completely defined by the applied fields. For this reason, this new inlet and trapping system represents a large step toward sensitive, high-resolution mass spectrometry into the megadalton range and beyond. (J Am Soc Mass Spectrom 2010, 21, 242-248) © 2010 American Society for Mass Spectrometry A rguably, the greatest advances in mass spectrometry of large molecules came with the introduction and development of electrospray ionization (ESI) [1] and matrix-assisted laser desorption ionization (MALDI) [2]. The creation of massive ions in vacuum was the start of a revolution in biological analysis using mass spectrometry. Unfortunately, the molecular weight range of mass specific biological species, such as proteins, RNA, DNA, and even viruses was much larger than the mass range of the mass spectrometer from which useful information could be obtained. Yet, the information was so valuable that a multitude of techniques and an entire industry was developed over the past 20-plus years so that these biological species could be analyzed using mass spectrometry. The essential thrust of the advances (beyond ionization) that have permitted the use of mass spectrometry for biological analysis has been in areas of sample preparation and analysis techniques, which allow analytes that are larger than the range of the mass spectrometer to be characterized with it anyway.The thrust of our efforts has been to increase the range of mass spectrometers where they achieve good resolution, mass accuracy, and sensitivity. Our analysis suggested that the overarching reason for the limitation of mass spectrometers in general was the expansioninduced kinetic energy distribution of the ions as they are injected in the mass spectrometer. The average and spread of the kinetic energy distribution of the ions expanding into vacuum monotonically increases with increasing mass. It is not difficult to compensate for the average increase for a particular type of ion; ho...

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Inductively Coupled Plasma Mass Spectrometry Analysis of Environmental Samples for the Quantification of Potentially Toxic Species

Teuma‐Castelletti

Sadiq

Beauchemin

2020

Encyclopedia of Analytical Chemistry

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The analysis of environmental samples is widely carried out to determine if a soil is safe for agricultural use, if water is safe to drink, if the air that we breathe can make us sick, how far reaching is pollution, if a contaminated site has been suitably remediated, etc. This article discusses how inductively coupled plasma mass spectrometry (ICPMS) can be used to this end. Indeed, with detection limits at the parts per trillion or even parts per quadrillion level, depending on the element and the instrument, ICPMS is very advantageous for the detection and quantification of toxic or potentially toxic species in environmental samples. This article describes sample preparation for ICPMS analysis and instrument calibration to yield accurate quantitative results. This includes the precautions that are often required, which vary depending on the type of analysis, sample matrix, instrument, and elements to be determined. It also includes techniques that can be coupled to ICPMS to increase its capabilities, such as laser ablation or electrothermal vaporization for direct solid analysis and liquid chromatography, gas chromatography, or capillary electrophoresis for speciation analysis, as speciation information is lost in the inductively coupled plasma (ICP) where all compounds are atomized.

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The Mass Filter: Design and Performance

Cited by 27 publications

References 20 publications

Laser-induced isotopic selectivity in the resonance ionization of Os

Laser-induced isotopic selectivity in the resonance ionization of Os

Controlling the expansion into vacuum—the enabling technology for trapping atmosphere-sampled particulate ions

Inductively Coupled Plasma Mass Spectrometry Analysis of Environmental Samples for the Quantification of Potentially Toxic Species

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