Effect of varying counterions on the sensitivity of electrohydrodynamic and fast atom bombardment mass spectrometry

Reynolds, Johnny D.; Cook, Kelsey D.

doi:10.1016/1044-0305(90)85040-s

Cited by 9 publications

(5 citation statements)

References 41 publications

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“…Louis, MO, Sigma grade). Reduction products were not among the dye impurities, as confirmed by electrohydrodynamic mass spectrometry [13]. The solution was not degassed prior to use.…”

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confidence: 81%

“…Due to the mounting arrange-current/area) could not be calculated. Because it is this flux, rather than simply current, which correlates with the extent of beam-induced damage [12][13][14], it would be useful to have an accurate and simple measure of the primary beam flux at the target. Such a measure would facilitate reproducibility and interlaboratory comparisons of FAB data.…”

mentioning

confidence: 99%

“…This study undertakes evaluation of beam-induced damage in a reference system as an indirect measure of primary flux. As candidates for monitoring beam-induced chemistry, we have examined indoine blue, bradykinin, and met-enkephalin in addition to the dyes listed in ref 13. Methylene blue reduction was the most sensitive to flux, and will be discussed here.…”

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confidence: 99%

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Determination of flux from a saddle field fast-atom bombardment gun

Boggess

Cook

1994

J. Am. Soc. Mass Spectrom.

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The flux or beam density (equivalent current/area) of xenon atoms striking the sample target from a saddle field fast-atom bombardment (FAB) gun has been compared with that from a cesium ion gun mounted on the same instrument. A shielded Faraday cup mounted on the end of a solids probe was used to measure directly the flux of the Cs(+) beam. Samples of methylene blue in glycerol solution were then exposed to the ion beam at different fluxes and the extents of reduction were measured. The extent of reduction varied linearly with flux up to a value of about 1.16 × 10(13) particles s(-1) cm(-2) (1.85 μ cm(-2)); above this level, the reduction effect appeared to saturate. FAB spectra were obtained from the same dye solution by using varying settings of the FAB gun. By comparing the extents of reduction of the dye from the two guns, the flux from the atom gun could be estimated. Observation of luminescence from a CsI-coated target allowed estimation of the area of the atom beam. The atom beam "equivalent current" could then be calculated by multiplying the flux times the area. It was noted that for given settings, the flux from the atom gun depended on the physical condition of the gun electrodes. With new electrodes, a flux ≥ 1.16 × 10(13) particles s(-1) cm(-2) was obtained with nominal gun emission currents of 0.60-1.0 mA. Electrodes used extensively, but freshly cleaned, provided a flux of ∼ 8 × 10(12) particles s(-1) cm(-2) at nominal emission currents of 0.40-1.0 mA. With dirty electrodes this flux could only be achieved at the highest (1.0 mA) emission current. This decline in performance occurs over a matter of months as a result of contamination and erosion of the electrodes during use. Such behavior can adversely affect spectral reproducibility even when nominal FAB gun voltage and emission current are carefully reproduced.

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“…Louis, MO, Sigma grade). Reduction products were not among the dye impurities, as confirmed by electrohydrodynamic mass spectrometry [13]. The solution was not degassed prior to use.…”

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confidence: 81%

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confidence: 99%

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Determination of flux from a saddle field fast-atom bombardment gun

Boggess

Cook

1994

J. Am. Soc. Mass Spectrom.

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“…Kelsey Cook of the University of Tennessee studied the effect of changes in the sample matrix of electrohydrodynamically ionized mono-and di-quaternary ammonium salts to model the solution processes that may be occurring in FAB and SIMS. These processes are difficult to monitor directly with these techniques because of interferences from the primary atom beam (8).…”

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confidence: 99%

Perspectives on the FUTURE OF ANALYTICAL MASS SPECTROMETRY

Basic¹,

Freeman²,

Yost³

1990

Anal. Chem.

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So read a billboard leading to the new city of Oak Ridge, TN, in late 1942. In direct contrast to the spirit of the "secret city" of the early 1940s Manhattan Project, attendees of the 43rd Annual Summer Symposium on Analytical Chemistry gathered July 24-27, 1990, to openly discuss the current and future directions of the rapidly growing field of analytical mass spectrometry (MS). The last summer symposium to feature analytical MS was held in 1981; it was time, therefore, to compare progress notes gathered over the past nine years and to focus once again on what has proven to be an active and exciting area of analytical chemistry.The symposium was hosted by W. D."Dub" Shults, director of the Division of Analytical Chemistry at Oak Ridge National Laboratory (ORNL)-the only division of its kind in the national labs-and chaired by Dave Donohue, also from ORNL. Active participation from the audience throughout the sym-posium was encouraged by program chair Graham Cooks of Purdue University, thus setting an atmosphere for the free exchange of ideas. The oral sessions commenced with a marathon Wednesday, reminiscent of the 24-hour-per-day pace of the early physicists of Oak Ridge; three sessions ran from 8:30 A.M. to 10:30 P.M., testing the stamina of experts and neophytes alike. Wednesday's sessions, coupled with those on Friday, amounted to 27 invited talks along with six submitted posters and a special graduate student session on Thursday. (Details of the symposium program can be found in the April 1,1990, issue of ANALYTICAL Chemistry.)In keeping with the theme of the fu-Perspectives on the FUTURE OF ANALYTICAL MASS SPECTROMETRY

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“…he choice of matrix [1][2][3][4][5][6][7][8][9][10][11][12][13][14] can have a dramatic effect on the appearance of fast atom bombardment (FAB) [15] mass spectra. Important matrix: properties that can affect spectral quality and appearance include viscosity [16][17][18], dielectric constant (which affects ion pairing [19][20][21][22][23][24][25][26][27][28][29][30][31][32]), solvation [33,34], and redox chemistry [10,[35][36][37][38][39][40][41].…”

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m-nitrobenzyl alcohol electrochemistry in fast atom bombardment mass spectrometry

Reynolds

Cook

Burn

et al. 1992

J. Am. Soc. Mass Spectrom.

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The efficacy of m-nitrobenzyl alcohol (NBA) as a solvent (matrix) for fast atom bombardment (FAB) mass spectrometry of a group of pyrazolate-bridged dirhodium A-frame complexes has been assessed. Although NBA is frequently used to mitigate the formation of artifacts in FAB/MS of organometallics and other materials susceptible to bombardment-induced reactions, substantial evidence indicates that such reactions cause the formation of artifacts in the spectra obtained here. Parallel absorption spectroscopic studies have established that NBA is capable of inducing both oxidation and reduction reactions independent of ion bombardment, depending on analyte reduction half-wave potential (E1/2). From the known electrochemistry of the complexes studied, it can be estimated that 1020 mV > E1/2 > 500 mV for the reaction of NBA serving as a reducing agent, while 500 mV > E1/2 > 424 mV for the reduction potential of NBA. However, in the presence of bombardment the former E1/2 must be at least as low as 356 mY, and the latter E1/2 must be at least as high as 1188 mY. The kinetics of redox reactions involving NBA, and therefore their influence on the appearance of FAB mass spectra, will be highly sample-dependent. However, this study illustrates an important potential role for redox reactions when NBA is used as a solvent, especially in the presence of bombardment in FAB/MS. Although analyte reaction products could be identified, substantial efforts aimed at identifying NBA oxidation and reduction products did not yield any definitive results due to the complexity of product mixtures.

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Effect of varying counterions on the sensitivity of electrohydrodynamic and fast atom bombardment mass spectrometry

Cited by 9 publications

References 41 publications

Determination of flux from a saddle field fast-atom bombardment gun

Determination of flux from a saddle field fast-atom bombardment gun

Perspectives on the FUTURE OF ANALYTICAL MASS SPECTROMETRY

m-nitrobenzyl alcohol electrochemistry in fast atom bombardment mass spectrometry

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