Comparison of photo-excitation of ions and collisional excitation using gases

Griffiths, Iwan W.; Mukhtar, Emad; March, Raymond E.; Harris, F.M.; Beynon, J. H.

doi:10.1016/0020-7381(81)80026-5

Cited by 80 publications

(26 citation statements)

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“…For electron capture dissociation (ECD) [1-6], the recombination energy (RE) resulting from capture of an electron from a multiply charged peptide or protein has been estimated to be between 4 and 7 eV [1,11,12], based in part on known or estimated thermochemical data. Dissociation may occur from excited electronic states or from ground states [13,14], so that the internal energy deposited into an ion may not be a singular value.Some ions have been used as chemical thermometers to measure internal energy deposition [15][16][17][18]. For example, dissociation of the molecular ion of n-butylbenzene results in formation of product ions at m/z 91 and 92, the ratio of which provides information about the average internal energy of the activated precursor [15,16].…”

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“…Some ions have been used as chemical thermometers to measure internal energy deposition [15][16][17][18]. For example, dissociation of the molecular ion of n-butylbenzene results in formation of product ions at m/z 91 and 92, the ratio of which provides information about the average internal energy of the activated precursor [15,16].…”

mentioning

confidence: 99%

“…For example, dissociation of the molecular ion of n-butylbenzene results in formation of product ions at m/z 91 and 92, the ratio of which provides information about the average internal energy of the activated precursor [15,16]. Ions that dissociate via sequential fragmentation and that have known threshold dissociation energies and similar dissociation entropies have also been used [18 -20].…”

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Measuring the extent and width of internal energy deposition in ion activation using nanocalorimetry

Donald

Williams

2010

J. Am. Soc. Mass Spectrom.

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The recombination energies resulting from electron capture by a positive ion can be accurately measured using hydrated ion nanocalorimetry in which the internal energy deposition is obtained from the number of water molecules lost from the reduced cluster. The width of the product ion distribution in these experiments is predominantly attributable to the distribution of energy that partitions into the translational and rotational modes of the water molecules that are lost. These results are consistent with a singular value for the recombination energy. For large clusters, the width of the energy distribution is consistent with rapid energy partitioning into internal vibrational modes. For some smaller clusters with high recombination energies, the measured product ion distribution is narrower than that calculated with a statistical model. These results indicate that initial water molecule loss occurs on the time scale of, or faster than energy randomization. This could be due to inherently slow internal conversion or it could be due to a multi-step process, such as initial ion-electron pair formation followed by reduction of the ion in the cluster. These results provide additional evidence for the accuracy with which condensed phase thermochemical values can be deduced from gaseous nanocalorimetry experiments. (J Am Soc Mass Spectrom 2010, 21, 615-625) © 2010 American Society for Mass Spectrometry C apture of a low-energy electron by a multiply charged peptide or protein can result in extensive and relatively non-selective fragmentation of the amide backbone, from which information about the amino acid sequence [1-3], post-translational modification sites [3][4][5], and higher-order structure [2,6,7] can be obtained. Similar fragmentation can be obtained by transferring an electron to the peptide or protein cation from a molecular anion [8] or from atoms [9,10]. These methods are being applied to both "bottom up" and "top-down" approaches to protein analysis.An important parameter in understanding how activated ions fragment is the extent of internal energy that is deposited in the activation step. For electron capture dissociation (ECD) [1-6], the recombination energy (RE) resulting from capture of an electron from a multiply charged peptide or protein has been estimated to be between 4 and 7 eV [1,11,12], based in part on known or estimated thermochemical data. Dissociation may occur from excited electronic states or from ground states [13,14], so that the internal energy deposited into an ion may not be a singular value.Some ions have been used as chemical thermometers to measure internal energy deposition [15][16][17][18]. For example, dissociation of the molecular ion of n-butylbenzene results in formation of product ions at m/z 91 and 92, the ratio of which provides information about the average internal energy of the activated precursor [15,16]. Ions that dissociate via sequential fragmentation and that have known threshold dissociation energies and similar dissociation entropies have also been used [18 -...

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Measuring the extent and width of internal energy deposition in ion activation using nanocalorimetry

Donald

Williams

2010

J. Am. Soc. Mass Spectrom.

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“…Thermometer ions can be used to determine the extent of ion activation on formation [20,23,28,36,37] and storage, [38] and during ion activation. [39][40][41][42][43] Benzylpyridiniums have been widely used as thermometer ions for characterizing the extent of energy deposition during ion formation, [37] primarily for spray [44] and laser desorption [45] -based ionization techniques. The bond dissociation energies (BDE) of substituted benzylpyridiniums depend strongly on the substituent, which can attenuate the electron density in the C-N bond.…”

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confidence: 99%

Internal Energy Deposition in Dielectric Barrier Discharge Ionization is Significantly Lower than in Direct Analysis in Real-Time Mass Spectrometry

2017

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The extent of internal energy deposition using three different plasma-based ionization mass spectrometry (MS) methods, atmospheric pressure chemical ionization (APCI), direct analysis in real time (DART), and active capillary dielectric barrier discharge ionization (DBDI), was investigated using benzylammonium 'thermometer' ions. Ions formed by DBDI were activated significantly less than those that were formed by DART and APCI under these conditions. Thermal ion activation by DART can be reduced slightly by positioning the DART source further from the capillary entrance to the MS and reducing the heat that is applied to metastable atoms exiting the DART source. For example, the average ion internal energy distribution decreased by less than 10 % (166.9 AE 0.3 to 152.2 AE 1.0 kJ mol À1) when the distance between the DART source and the MS was increased by 250 % (10 to 25 mm). By lowering the DART temperature from 350 to 1508C, the internal energy distributions of the thermometer ions decreased by ,15 % (169.93 AE 0.83 to 150.21 AE 0.52 kJ mol À1). Positioning the DART source nozzle more than 25 mm from the entrance to the MS and decreasing the DART temperature further resulted in a significant decrease in ion signal. Thus, varying the major DART ion source parameters had minimal impact on the 'softness' of the DART ion source under these conditions. Overall, these data indicate that DBDI can be a significantly 'softer' ion source than two of the most widely used plasma-based ion sources that are commercially available.

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“…Beynon and coworkers [17][18][19] reported an approximate thermometer method in which branching ratios were used to characterize energy deposition associated with photodissociation. Wysocki et al [20] have reported the use of so-called thermometer molecules to measure internal energy distributions P(ε) of gas-phase ions.…”

Section: Introductionmentioning

confidence: 99%

Potential crossing position in electron transfer of a doubly charged ion and an alkali metal target measured using thermometer molecule W(CO)6

Hayakawa

Minami

Iwamoto

et al. 2007

International Journal of Mass Spectrometry

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Comparison of photo-excitation of ions and collisional excitation using gases

Cited by 80 publications

References 10 publications

Measuring the extent and width of internal energy deposition in ion activation using nanocalorimetry

Measuring the extent and width of internal energy deposition in ion activation using nanocalorimetry

Internal Energy Deposition in Dielectric Barrier Discharge Ionization is Significantly Lower than in Direct Analysis in Real-Time Mass Spectrometry

Potential crossing position in electron transfer of a doubly charged ion and an alkali metal target measured using thermometer molecule W(CO)6

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