Reduction in Desorption Mass Spectrometry: Multiple Protonation on Flavins without Charge Increment.

Itoh, Yoshiyuki; Ohashi, Yoko; Shibue, Toshimichi; Hayashi, Akio; Maki, Shôjirô; Hirano, Takashi; Niwa, Haruki

doi:10.5702/massspec.50.52

Cited by 22 publications

(30 citation statements)

References 11 publications

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“…13) To further investigate proton involvement, riboflavin was analyzed by DIOS-MS using various deuterated solvents: methanol-d 4 ῌ were high compared with the control, indicating the incorporation of deuterium (Figs. 2c῍e).…”

Section: Resultsmentioning

confidence: 99%

“…12) As reported by Itoh et al, flavin-containing compounds, riboflavin, riboflavin 5῏-phosphate, and flavin-adenine dinucleotide, were reduced by MALDI and fast atom bombardment (FAB), whereas such reduction was not observed in the ESI mass spectrum. 13 ῌ ions were dependent on the matrix species used for MALDI. 13) Also, photo-induced dissociation followed by reduction was suggested in the MALDI-MS of nitrotyrosine, in which the NO 2 moiety is partially changed into an amine (NH 2 ).…”

Section: Introductionmentioning

confidence: 99%

“…13 ῌ ions were dependent on the matrix species used for MALDI. 13) Also, photo-induced dissociation followed by reduction was suggested in the MALDI-MS of nitrotyrosine, in which the NO 2 moiety is partially changed into an amine (NH 2 ). 14), 15) In the case of S-nitrosocysteine, only the reduced form (SH), not the SNO form, was observed in the MALDI mass spectra of the SNO-containing peptides and proteins, while the intact molecular ion species with SNO could be identified by the ESI mass spectrum.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reduction of Cu(II) and Riboflavin in DIOS Mass Spectrometry

Okuno

Arakawa

Wada

2004

J. Mass Spectrom. Soc. Jpn.

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Understanding ion-molecular reactions is suggested to be essential to delineating the mechanisms of matrix-assisted laser desorption/ionization (MALDI) and related ionization methods. To examine the implications of matrix-analyte reactions in the reduction observed in MALDI, copper(II) chloride and riboflavin were analyzed by desorption/ionization on porous silicon (DIOS) mass spectrometry. This system does not require a matrix for soft laser desorption/ionization. The two susbstances were reduced by DIOS as well, and the reduction of riboflavin was accelerated using water as a solvent, as reported in MALDI. The results indicated that target-analyte electron transfer occurs in LDI, although the possibility of matrix-analyte electron transfer in MALDI cannot be excluded.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Reduction of Cu(II) and Riboflavin in DIOS Mass Spectrometry

Okuno

Arakawa

Wada

2004

J. Mass Spectrom. Soc. Jpn.

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“…16 It is postulated that protonation (by the matrix), with concomitant electron transfer in the gas phase and an energy contribution from UV-laser irradiation, could induce the hydrogenation of the double bond adjacent to nitrogen in the pyridine ring of PA, thus resulting in the production of …”

Section: Letter To the Editor 3609mentioning

confidence: 99%

Mechanistic elucidation of the formation of reduced 2‐aminopyridine‐derivatized oligosaccharides and their application in matrix‐assisted laser desorption/ionization mass spectrometry

Sekiya

Yamaguchi

Kato

et al. 2005

Rapid Comm Mass Spectrometry

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“…17 In the case of nitrotyrosine, the NO2 moiety is partially converted into NH2, probably due to reduction after photo-induced dissociation by UV laser irradiation. 18,19 Similarly, the S-nitrosylated cysteine, Cys(SNO), in peptides is completely converted to cysteine, Cys(SH), in MALDI.…”

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confidence: 99%

Oxidation of Ferrocene Derivatives in Desorption/Ionization on Porous Silicon

2005

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Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is currently an indispensable method for analyzing biomolecules and synthetic polymers. [1][2][3][4][5][6] While the mechanism of ionization is largely unknown, physical data on the ionization potentials and the gas-phase acidity or basicity have been accumulating, and the roles of the matrix-matrix, matrix-analyte and analyte-analyte reactions in both primary and secondary ionization events have been evaluated in some detail. [7][8][9][10][11][12][13][14][15][16] These studies have suggested the secondary ionmolecule reactions in the plume to be essential to understanding the process of ionization and the mass spectrum. 7,9,11 Some analytes are reduced by these reactions as follows: Copper(II) ions are reduced by laser desorption/ionization (LDI) with or without a chemical matrix. 16Flavin-containing compounds, such as riboflavin, riboflavin 5′-phosphate and flavin-adenine dinucleotide, are reduced in MALDI and fast atom bombardment (FAB) ionization, but not in electrospray ionization, as reported by Itoh et al., who also found that the reduction levels depend on the matrix molecule types. 17 In the case of nitrotyrosine, the NO2 moiety is partially converted into NH2, probably due to reduction after photo-induced dissociation by UV laser irradiation. 18,19 Similarly, the S-nitrosylated cysteine, Cys(SNO), in peptides is completely converted to cysteine, Cys(SH), in MALDI. 20,21 Different mechanisms, such as electron capture and charge exchange with the chemical matrix, have been proposed to account for the reductions in MALDI. 8,9 A line of studies has indicated that free electrons are formed by photoelectric emission from the metal/dielectric-substance interface. [22][23][24][25] The metal sample target is not the photoelectron source, because the work function of metals is greater than the photon energy. 23 The presence of matrix molecules or analytes placed on a metal target enhances electron emission via band bending and the associated reduction in work function. 22,23 Thus, electron transfer from the sample target would be essential for understanding the analyte reduction in LDI.In desorption/ionization on porous silicon, termed DIOS, 26 analytes are deposited on a silicon chip, which is prepared by electrochemical anodization or chemical etching of crystalline silicon, for LDI without the addition of a chemical matrix. The DIOS mass spectra are thus free of cluster ions of the matrix, facilitating identification of the ions of small analyte molecules. DIOS-MS has been applied to various kinds of compounds, such as peptides, natural products, small organic molecules and synthetic polymers. [26][27][28][29][30][31][32][33][34][35][36] The ionization efficiency of DIOS relies on a porous scaffold providing a sufficient surface area to retain analytes, and on the UV-absorptive property, which affords the transfer of laser energy to analytes. 26,27 In contrast to MALDI, chemical reactions in a plume composed of analytes and the sample ma...

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Reduction in Desorption Mass Spectrometry: Multiple Protonation on Flavins without Charge Increment.

Cited by 22 publications

References 11 publications

Reduction of Cu(II) and Riboflavin in DIOS Mass Spectrometry

Reduction of Cu(II) and Riboflavin in DIOS Mass Spectrometry

Mechanistic elucidation of the formation of reduced 2‐aminopyridine‐derivatized oligosaccharides and their application in matrix‐assisted laser desorption/ionization mass spectrometry

Oxidation of Ferrocene Derivatives in Desorption/Ionization on Porous Silicon

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