Tandem mass spectrometry: structural and stereochemical information from steroids

For tandem mass spectrometry, the Fourier transform instrument exhibits advantages for the use of collisionally-activated dissociation (CAD). The CAD energy deposited in larger ions can be greatly increased by extending the collision time to as much as 120 s, and the efficiency of trapping and measuring CAD product ions is many times greater than that found for triple-quadrupole or magnetic sector instruments, although the increased pressure from the collision gas is an offsetting disadvantage. A novel system that uses the same laser for photodesorption of ions and their subsequent photodissociation can produce complete dissociation of larger oligopeptide ions and unusually abundant fragment ions. In comparison to CAD, much more internal energy can be deposited in the primary ions using 193-nm photons, sufficient to dissociate peptide ions of m/z > 2000. Mass spectra closely resembling ion photodissociation spectra can also be obtained by' neutral photodissociation (193-nm laser irradiation of the sample) followed by ion photodesorption.

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“…For alamethicin I, this same series is observed for amino adds 4-13 but is shifted by -14 u for fragments with m]z > 460. 2…”

Section: ------------R------------mentioning

confidence: 99%

Efficiency of collisionally-activated dissociation and 193-nm photodissociation of peptide ions in fourier transform mass spectrometry

Williams

Furlong

McLafferty

1990

J. Am. Soc. Mass Spectrom.

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107

109

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“…The concept of charge-remote (originally called remote-site fragmentation) was first described in 1983 as observed on a unique three-sector mass spectrometer [21, 22]. This instrumentation was later used to demonstrate the charge-remote fragmentations of a series of bile acids and bile salt conjugates [23] and other steroids [24, 25]. Tomer and Gross [26] then reported in 1988 that both charge-remote and charge-proximate fragmentations occur for bile salts, steroid sulfates, and glucuronides, showing that nearly complete structure determination of steroid rings could be achieved.…”

Section: Introductionmentioning

confidence: 99%

High-Energy Collision-Induced Dissociation by MALDI TOF/TOF Causes Charge-Remote Fragmentation of Steroid Sulfates

Yan

Ubukata

Cody

et al. 2014

J. Am. Soc. Mass Spectrom.

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A method for structural elucidation of biomolecules dating to the 1980s utilized high-energy collisions (~10 keV, laboratory frame) that induced charge-remote fragmentations (CRF), a class of fragmentations particularly informative for lipids, steroids, surfactants, and peptides. Unfortunately, the capability for high-energy activation has largely disappeared with the demise of magnetic sector instruments. With the latest designs of tandem time-of-flight mass spectrometers (TOF/TOF), however, this capability is now being restored to coincide with the renewed interest in metabolites and lipids including steroid-sulfates and other steroid metabolites. For these metabolites, structure determinations are required at concentration levels below that appropriate for NMR. To meet this need, we explored CRF with TOF/TOF mass spectrometry for two groups of steroid sulfates, 3-sulfates and 21-sulfates. We demonstrated that the current generation of MALDI TOF/TOF instruments can generate charge-remote-fragmentations for these materials. The resulting collision-induced dissociation (CID) spectra are useful for positional isomer differentiation and very often allow the complete structure determination of the steroid. We also propose a new nomenclature that directly indicates the cleavage sites on the steroid ring with carbon numbers.

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“…Its high-resolution MS/MS applications were valuable for diverse studies (86)(87)(88), and this so-called four-sector became the premier commercial MS instrument: Well over 100 units were sold over the next decade. However, we were able to perform MS/MS only on a heptadecapeptide, MW 2094, with ionization by fast atom bombardment (86).…”

Section: Figurementioning

confidence: 99%

A Century of Progress in Molecular Mass Spectrometry

McLafferty

2011

Annual Rev. Anal. Chem.

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The first mass spectrum of a molecule was measured by J.J. Thomson in 1910. Mass spectrometry (MS) soon became crucial to the study of isotopes and atomic weights and to the development of atomic weapons for World War II. Its notable applications to molecules began with the quantitative analysis of light hydrocarbons during World War II. When I joined the Dow Chemical Company in 1950, MS was not favored by organic chemists. This situation improved only with an increased understanding of gaseous ion chemistry, which was obtained through the use of extensive reference data. Gas chromatography–MS was developed in 1956, and tandem MS was first used a decade later. In neutralization-reionization MS, an unusual, unstable species is prepared by ion-beam neutralization and characterized by reionization. Electrospray ionization of a protein mixture produces its corresponding ionized molecules. In top-down proteomics, ions from an individual component can be mass separated and subjected to collision-activated and electron-capture dissociation to provide extensive sequence information.

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Tandem mass spectrometry: structural and stereochemical information from steroids

Cited by 22 publications

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Efficiency of collisionally-activated dissociation and 193-nm photodissociation of peptide ions in fourier transform mass spectrometry

Efficiency of collisionally-activated dissociation and 193-nm photodissociation of peptide ions in fourier transform mass spectrometry

High-Energy Collision-Induced Dissociation by MALDI TOF/TOF Causes Charge-Remote Fragmentation of Steroid Sulfates

A Century of Progress in Molecular Mass Spectrometry

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