Using a superconducting tunnel junction detector to measure the secondary electron emission efficiency for a microchannel plate detector bombarded by large molecular ions

Westmacott, Garrett; Frank, Matthias; Labov, S. E.; Benner, W. Henry

doi:10.1002/1097-0231(20001015)14:19<1854::aid-rcm102>3.0.co;2-m

Cited by 58 publications

(61 citation statements)

References 18 publications

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“…The last type of correction involves the m/z bias of the microchannel plate (MCP) detector. The efficiency with which an ion generates a secondary electron in the MCP has been shown to vary as follows [32][33][34]:…”

Section: Mass Spectrometry and Data Analysismentioning

confidence: 99%

Controlling gas-phase reactions for efficient charge reduction electrospray mass spectrometry of intact proteins

Frey

Lin

Westphall

et al. 2005

J. Am. Soc. Mass Spectrom.

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Charge reduction electrospray mass spectrometry (CREMS) reduces the charge states of electrospray-generated ions, which concentrates the ions from a protein into fewer peaks spread over a larger m/z range, thereby increasing peak separation and decreasing spectral congestion. An optimized design for a CREMS source is described that provides an order-ofmagnitude increase in sensitivity compared to previous designs and provides control over the extent of charge reduction. Either a corona discharge or an ␣-particle source was employed to generate anions that abstract protons from electrosprayed protein cations. These desired ion/ion proton transfer reactions predominated, but some oxidation and ion-attachment reactions also occurred, leading to new peaks or mass-shifted broader peaks while decreasing signal intensity. The species producing these deleterious side-reactions were identified, and conditions were found that prevented their formation. Spectrometer m/z biases were examined because of their effect upon the signal intensity of higher m/z charge-reduced protein ions. The utility of this atmospheric pressure CREMS was demonstrated using a cell lysate fraction from E. coli. The spectral simplification afforded by CREMS reveals more proteins than are observed without charge reduction. (J Am Soc Mass Spectrom 2005, 16, 1876 -1887

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Section: Mass Spectrometry and Data Analysismentioning

confidence: 99%

Controlling gas-phase reactions for efficient charge reduction electrospray mass spectrometry of intact proteins

Frey

Lin

Westphall

et al. 2005

J. Am. Soc. Mass Spectrom.

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“…Thus, above m/z 50 000, two protein species with small mass differences (potentially up to several kDa's) will not be well resolved. Second, ion detection in TOF-MS using conventional microchannel plate detectors is a process which is velocity-dependent [60][61][62][63]. This implies that higher molecular weight ions (having lower velocities) have lower probabilities of being detected.…”

Section: Perspectivesmentioning

confidence: 99%

Direct profiling and imaging of peptides and proteins from mammalian cells and tissue sections by mass spectrometry

2002

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Mass spectrometry can be used to map the distribution of targeted compounds in tissue, providing important molecular information in many areas of biological research. Matrix assisted laser desorption/ionization - time of flight - mass spectrometry (MALDI-TOF-MS) is well suited for the analysis of tissue samples with a spatial resolution of about 30 microm for compounds in a mass range from 1000 to over 50 000 Da. Direct analysis of tissue sections requires spotting or coating of the tissue with a matrix compound typically sinapinic acid or other cinnamic acid analogs. A raster of this sample by the laser beam and subsequent mass analysis of the desorbed ions can record molecular intensities throughout the section. The overall process is illustrated by profiling and imaging of mouse epididymis sections where protein activity changes markedly throughout the section.

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“…They demonstrated high m/z analysis sensitivity, where ion velocity dependence of conventional detectors show reduced signal response [6,7]. Since then, results have been obtained using STJ cryodetection for ultra-high mass macromolecules such as 13 MDa bacteriophage capsids, 2 MDa polystyrene, von Willebrand factor (1.5 MDa), IgM (1 MDa), and heterogeneous systems such as ferritin (~850 kDa) [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Characterization of ZnO Nanoparticles using Superconducting Tunnel Junction Cryodetection Mass Spectrometry

Plath

Wang

Yan

et al. 2017

J. Am. Soc. Mass Spectrom.

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Zinc oxide (ZnO) nanoparticles coated with either n-octylamine (OA) or α-amino poly(styrene-co-acrylonitrile) (PSAN) ligands (L) have been analyzed using laser desorption/ionization and matrix assisted laser desorption/ionization (MALDI) time-of-flight (TOF) superconducting tunnel junction (STJ) cryodetection mass spectrometry. STJ cryodetection has the advantage of high m/z detection and allows for the determination of average molecular weights and dispersities for 500-600 kDa ZnO-L nanoparticles. The ability to detect the relative energies deposited into the STJs has allowed for investigation of ZnO-L metastable fragmentation. ZnO-L precursor ions gain enough internal energy during the MALDI process to undergo metastable fragmentation in the flight tube. These fragments produced a lower energy peak, which was assigned as ligand-stripped ZnO cores whereas the individual ligands were at too low of an energy to be observed. From these STJ energy resolved peaks, the average weight percentage of inorganic material making up the nanoparticle was determined, where ZnO-OA and ZnO-PSAN nanoparticles are comprised of ~62% and ~68% wt ZnO, respectively. In one example, grafting densities were calculated based on the metastable fragmentation of ligands from the core to be 16 and 1.1 nm for ZnO-OA and ZnO-PSAN, respectively, and compared with values determined by thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). Graphical Abstract ᅟ.

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Using a superconducting tunnel junction detector to measure the secondary electron emission efficiency for a microchannel plate detector bombarded by large molecular ions

Cited by 58 publications

References 18 publications

Controlling gas-phase reactions for efficient charge reduction electrospray mass spectrometry of intact proteins

Controlling gas-phase reactions for efficient charge reduction electrospray mass spectrometry of intact proteins

Direct profiling and imaging of peptides and proteins from mammalian cells and tissue sections by mass spectrometry

Characterization of ZnO Nanoparticles using Superconducting Tunnel Junction Cryodetection Mass Spectrometry

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