Determination of field-ionization relative sensitivities for the analysis of coal-derived liquids and their correlation with low-voltage electron-impact relative sensitivities

Scheppele, Stuart E.; Grizzle, P. L.; Greenwood, G.J.; Marriott, Terry; Perreira, N.B.

doi:10.1021/ac50008a015

Cited by 59 publications

(30 citation statements)

References 29 publications

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“…The origin of this difference is not clear although it assumably reflects differences in the compounds present in and the composition of the former mixture compared to the latter 3 mixtures. It is important to note that the sensitivity of 1-ethylnaphthalene relative to ethylbenzene (1.02 ± 0.04) is consistent with previous results obtained for methyl-and dimethylnaphthalene (4). Table IV also contains relative sensitivity data for a mixture containing ethylbenzene, decalin, and decane.…”

Section: Determination Of Relative Sensitivities For Field Ionizationsupporting

confidence: 87%

Mass spectrometric analytical services and research activities to support coal-liquid characterization research. Quarterly report, December 9, 1976--March 8, 1977

Scheppele¹

1977

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Section: Determination Of Relative Sensitivities For Field Ionizationsupporting

confidence: 87%

Mass spectrometric analytical services and research activities to support coal-liquid characterization research. Quarterly report, December 9, 1976--March 8, 1977

Scheppele¹

1977

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“…, / for each value of a,b, and c, and η = 4 or 3 for even or odd values of a, respectively. The available data indicate that the mole sensitivities, s(my)<, for ionization of aromatic compounds of present interest by both low-voltage electrons (44,45) and high-electric fields (46) …”

Section: Methodsmentioning

confidence: 99%

“…The FI/MS molecular-ion intensities for both the oil and asphaltene neutral aromatic fractions were converted to carbon-number distributions assuming equal relative mole sensitivities for all specific-Z series and using average relative mole sensitivities for each specific-Z series calculated from either the experimental relative mole sensitivities for individual compounds or from the correlation of these values with specific-Z values (46). Comparison of the weight percentages in Columns 2 and 3, and 5 and 6 in Table I is consistent with the suggestion (46) that use of the latter approximation in processing FI/MS ion intensities results in acceptable quantitative distributions for fractions comprised of related compound types.…”

Section: Figure 3 Chromatographic Separation Of Asphaltenesmentioning

confidence: 99%

Consequences of the Mass Spectrometric and Infrared Analysis of Oils and Asphaltenes for the Chemistry of Coal Liquefaction

Scheppele

Benson

Greenwood

et al. 1982

Advances in Chemistry

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Oils and asphaltenes are generally assumed to be key intermediates in coal liquefaction. Since fundamental chemical/ mathematical principles require compositionally unique fractions, mass spectrometry and infrared spectroscopy were employed to obtain detailed molecular analyses of fractionated coal-liquid-derived oils and asphaltenes. The asphaltenes contain higher molecular weight homologs in many specific-Z series and different compound types than do the oils. However, both fractions contain appreciable quantities of compound types equivalent in molecular formula and, hence, assumably in molecular structure. The chemical/physical properties of oils and asphaltenes are not describable in terms of average (hypothetical) molecular structures. The lack of unique oil and asphaltene compositions necessitates detailed molecular analysis as a prerequisite for understanding, assessing, and controlling the chemical/physical phenomena intrinsic to production and processing of coal liquids.T he concept of preasphaltenes, asphaltenes, and oils is of historical significance in the development of the science and technology of coal liquefaction (J). This concept is routinely employed in attempts to understand, assess,

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“…From this, the A · + ion formation can be explained by the mechanism of eld ionization (FI) with an e ect of electron tunneling, 19,20) because the FI mass spectra are generally lacking in fragment ions. 21,22) e in uence of positivepolarity high electric eld (+hef ) on analyte molecules A may result in the induction e ects such as molecular orbital distortion and polarization.…”

Section: Mass Spectra Of Benzene and Its Derivatives By Positive-ion mentioning

confidence: 99%

Ionization Capabilities of Hydronium Ions and High Electric Fields Produced by Atmospheric Pressure Corona Discharge

2017

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Atmospheric pressure corona discharge (APCD) was applied to the ionization of volatile organic compounds. e mass spectra of analytes having aromatic, phenolic, anilinic, basic and aliphatic in nature were obtained by using vapor supply and liquid smear supply methods. e vapor supply method mainly gave protonated analytes [A+H] + caused by proton transfer from hydronium ion H 3 O + , except for benzene, toluene and n-hexane that have lower proton a nity. e use of the liquid smear supply method resulted in the formation of molecular ion A · + and/or dehydride analyte [A−H] + , according to the nature of analytes used. e formation of A · + without fragment ions could be explained by the electron tunneling via high electric elds 10 8 V/m at the tip of the corona needle. e dehydride analytes [A−H] + observed in the mass spectra of n-hexane, di-and tributylamines may be explained by the hydride abstraction from the alkyl chains by the hydronium ion. e hydronium ion can play the two-roles for analytes, i.e., the proton donor to form [A+H] + and the hydride acceptor to form [A−H]

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Determination of field-ionization relative sensitivities for the analysis of coal-derived liquids and their correlation with low-voltage electron-impact relative sensitivities

Cited by 59 publications

References 29 publications

Mass spectrometric analytical services and research activities to support coal-liquid characterization research. Quarterly report, December 9, 1976--March 8, 1977

Mass spectrometric analytical services and research activities to support coal-liquid characterization research. Quarterly report, December 9, 1976--March 8, 1977

Consequences of the Mass Spectrometric and Infrared Analysis of Oils and Asphaltenes for the Chemistry of Coal Liquefaction

Ionization Capabilities of Hydronium Ions and High Electric Fields Produced by Atmospheric Pressure Corona Discharge

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