Gas-phase ion equilibria studies of protons and chloride ions in propanol and acetone

Hiraoka, Kenzo; Morise, K.; Nishijima, Tadashi; Nakamura, Shizuo; Nakazato, Masaki; Ohkuma, K.

doi:10.1016/0168-1176(86)87071-9

Cited by 16 publications

(9 citation statements)

References 7 publications

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“…Uncertainty estimates for Δ H ° (kJ/mol) and Δ S ° (J/(mol K)) and number of determinations: A 2 H + + W, 2.1, 8.4, 6; A 2 H + + A, 5.0, 19.2, 1; A 2 H + + 2W, 6.7, 23.4, 3; A 2 H + + A + W, 10.0, 33.5, 5; A 2 W 2 H + + W, 2.1, 7.5, 2; A 3 WH + + W, 2.9, 13.4, 1; A 2 W 3 H + + W, 4.2, 17.2, 1; A 3 W 2 H + + W, 3.8, 16.7, 1; A 3 W 2 H + + A, 6.7, 28.9, 1. b Protonation thermochemistry from refs , , and 31. c Average of present work and literature values from ref . d Present work; compare with Δ H ° = −51.0 kJ/mol and Δ S ° = −96.2 J/(mol K) from refs and . e From Δ G ° 215 = −20.9 kJ/mol, Δ S ° estimated as shown.…”

Section: Experimental and Computational Methodsmentioning

confidence: 66%

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Ionic Hydrogen Bonds in Bioenergetics. 3. Proton Transport in Membranes, Modeled by Ketone/Water Clusters

Meot‐Ner

Scheiner

1998

J. Am. Chem. Soc.

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Hydrogen bond networks in protonated acetone/water clusters are stabilized by H3O+(Me2CO)2 centers, and the stabilizaton increases with further acetone content. For example, proton transfer from neat water (H2O)6H+ clusters to form mixed (Me2CO)3(H2O)3H+ clusters is exothermic by 80 kJ/mol (19 kcal/mol), due to strong hydrogen bonding of the carbonyl groups; in a series of mixed clusters B3(H2O)3H+, the stability of the hydrogen bond network correlates with the proton affinities PA(B). In diketone models of adjacent peptide links, the proton is stabilized by internal hydrogen bonds between the carbonyl groups. The internal bonds can be significant, for example, 31 kJ/mol (7 kcal/mol) in (MeCOCH2CH2COMe)H+, but proton transfer through the internal bond has a high barrier. However, water molecules can bridge between the CO groups. In these bridges, the proton remains on an H3O+ center, in both acetone/water and diketone/water systems. With a further H2O molecule, the diketone/water cluster (MeCOCH2CH2COMe)(H2O)2H+ and diamide/water clusters form two-water H3O+···H2O bridges, which allow proton transfer between the CO groups with a small barrier of <12 kJ/mol (<3 kcal/mol). The cluster models suggest several roles for hydrogen bonds in proton transport through membranes. (1) Ionic hydrogen bonds involving polar amide groups stabilize ions by up to 135 kJ/mol (32 kcal/mol) in clusters and can similarly stabilize ions in membrane water chains and enzyme centers. (2) The proton can remain on an H3O+ center and, therefore, remain delocalized and mobile in water chains, despite the stronger basicities of the surrounding amide groups. This effect results from electrostatic balancing of opposing peptide amide dipoles. (3) In the water chains, H3O+···H2O bridges between peptide amide groups can provide low-energy pathways for proton transport.

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Section: Experimental and Computational Methodsmentioning

confidence: 66%

“…e From Δ G ° 215 = −20.9 kJ/mol, Δ S ° estimated as shown. Compare with Δ H ° = −35.6 kJ/mol and Δ S ° = −71 J/(mol K) from refs . f From ref .…”

Section: Experimental and Computational Methodsmentioning

confidence: 87%

Ionic Hydrogen Bonds in Bioenergetics. 3. Proton Transport in Membranes, Modeled by Ketone/Water Clusters

Meot‐Ner

Scheiner

1998

J. Am. Chem. Soc.

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“…1,2) is is not a very high value in our present day standard, but it was much higher than that of EI in those days, and in some cases, di erential pumping system was necessary to separate the analyzer/detector from the ion source vacuum. e detection of "macroions" generated from the electrospray in Fenn's early experiment had led to the rapid development of modern atmospheric pressure ionization mass spectrometry (API-MS).…”

Section: Introductionmentioning

confidence: 99%

“…11a, the protein solvent is 2 v/v% formic acid aqueous solution which has recently become a standard reagent for the chemical digestion. Except for the peptide fragment [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], all other hydrolysis products are due to the cleavage at the Asp sites. Comparison was also done with acetic acids (Fig.…”

Section: Rapid In-situ Protein Digestion Ms With Superheated Esimentioning

confidence: 99%

When API Mass Spectrometry Meets Super Atmospheric Pressure Ion Sources

Chen

2015

Mass Spectrometry

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“…When the reagent gas is intentionally introduced, the EI source becomes a chemical ionization (CI) source, 1) an ionization method which is so er than EI. e early term of "high pressure ion source" refers to this type of ionization taking place under the gas pressure of 0.1 to 5 Torr, 2,3) and it is still widely used for the study of ion-molecule reaction. 4) e atmospheric pressure chemical ionization (APCI), 5,6) a popular ionization method used in liquid chromatography mass spectrometry along with ESI, is, as denoted by its name, a variant of CI done under atmospheric pressure (∼10 5 Pa) condition.…”

Section: Introductionmentioning

confidence: 99%

Super-Atmospheric Pressure Ion Sources: Application and Coupling to API Mass Spectrometer

2014

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Pressurizing the ionization source to gas pressure greater than atmospheric pressure is a new tactic aimed at further improving the performance of atmospheric pressure ionization (API) sources. In principle, all API sources, such as ESI, APCI and AP-MALDI, can be operated at pressure higher than 1 atm if suitable vacuum interface is available. e gas pressure in the ion source can have di erent role for di erent ionization. For example, in the case of ESI, stable electrospray could be sustained for high surface tension liquid (e.g., pure water) under super-atmospheric pressure, owing to the absence of electric discharge. Even for nanoESI, which is known to work well with aqueous solution, its stability and sensitivity were found to be enhanced, particularly in the negative mode when the ion source was pressurized. For the gas phase ionization like APCI, measurement of gaseous compound also showed an increase in ion intensity with the ion source pressure until an optimum pressure at around 4-5 atm. e enhancement was due to the increased collision frequency among reactant ion and analyte that promoted the ion/molecule reaction and a higher intake rate of gas to the mass spectrometer. Because the design of vacuum interface for API instrument is based on the upstream pressure of 1 atm, some coupling aspects need to be considered when connecting the high pressure ion source to the mass spectrometer. Several coupling strategies are discussed in this paper.

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Gas-phase ion equilibria studies of protons and chloride ions in propanol and acetone

Cited by 16 publications

References 7 publications

Ionic Hydrogen Bonds in Bioenergetics. 3. Proton Transport in Membranes, Modeled by Ketone/Water Clusters

Ionic Hydrogen Bonds in Bioenergetics. 3. Proton Transport in Membranes, Modeled by Ketone/Water Clusters

When API Mass Spectrometry Meets Super Atmospheric Pressure Ion Sources

Super-Atmospheric Pressure Ion Sources: Application and Coupling to API Mass Spectrometer

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