Gas Chromatography of Isotopic Molecules on Open Tubular Columns.

Bruner, F.; Cartoni, G.P.; Liberti, A.

doi:10.1021/ac60234a035

Cited by 91 publications

(32 citation statements)

References 7 publications

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“…A similar inverse isotope effect is frequently observed during gas phase/liquid-phase partitioning in GC columns (22)(23)(24)(25), which results in a slightly faster elution of molecules with heavy isotopes than molecules with light isotopes during GC separation. The SPME fiber has a similar chemical composition as nonpolar GC columns (dimethylpolysiloxane).…”

Section: Discussionsupporting

confidence: 61%

Determination of Compound-Specific Carbon Isotope Ratios of Chlorinated Methanes, Ethanes, and Ethenes in Aqueous Samples

Hunkeler

Aravena

2000

Environ. Sci. Technol.

114

129

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Compound-specific carbon isotope ratio analysis is a promising tool to assess the origin and fate of organic contaminants in groundwater. The aim of this study was to develop and evaluate a reliable, fast method to determine carbon isotope ratios of chlorinated methanes, ethanes, and ethenes in aqueous samples. Direct solid-phase microextraction (dSPME) and headspace solid-phase microextraction (hSPME) were selected as extraction method and compared to headspace equilibration. For dSPME and hSPME, deviations between carbon isotope ratios in the aqueous phase and on the SPME fiber were e 0.40‰. For headspace equilibration, molecules in the gas phase were enriched in 13 C compared to molecules in the aqueous phase by up to 1.46‰, in particular for chlorinated methanes. The absence of significant carbon isotope fractionation during dSPME and hSPME could be explained by the fact that both the aqueous phase and the SPME fiber coating discriminate against molecules with 13 C to a similar degree, and thus no net carbon isotope fractionation occurs. If aqueous phase/gas-phase carbon isotope fractionation during headspace equilibration is taken into account, all methods, dSPME, hSPME, and headspace equilibration, provide accurate δ 13 C values with a similar precision. Direct SPME was the most sensitive method with detection limits as low as 130 ppb.

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Section: Discussionsupporting

confidence: 61%

Determination of Compound-Specific Carbon Isotope Ratios of Chlorinated Methanes, Ethanes, and Ethenes in Aqueous Samples

Hunkeler

Aravena

2000

Environ. Sci. Technol.

114

129

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“…This behaviour has already been observed for methane [ll] [25] and acetylene [Zl] on solid stationary phases. Table 4 gives the coefficients for eq.…”

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confidence: 69%

The Gas‐Chromatographic Retention Indices of Deuterated Compounds

Gäumann

Bonzo

1973

Helvetica Chimica Acta

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Zusammenfassung. Die h d e r u n g des Retentionsindex mit dem Deuterierungsgrad ciniger Verbindungen wurden als Funktion der Temperatur und der stationaren Phase untersucht. Er zeigt grossc Regelmassigkeiten in der Abhangigkeit von der Anzahl der Deuteriumatome in der Molekel und von der stationaren Phase. Die Resultate gestatten eine Abschatzung der relativen Fluchtigkeit G( einer deuterierten Verbindung und der h d e r u n g der thermodynamischen Zustandsfunktionen bei der Deuterierung. With this in mind, we published a procedure that permits the determination of the isotopic distribution in a compound, even when the gas-chromatographic resolution does not allow the determination of the different isotope-isomeric species separately [24]. We have since used gas-chromatographic analysis as a routine procedure to measure deuterium distributions in different compounds. A literature survey shows that there is very little systematic data accumulated in this field. This in why we have collected some of our results of the past few years in order to facilitate research in this field. Because of the author's interest, most of the compounds studied are paraffins. We think that this should not invalidate some of the generalizations found, however.

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“…It should be noted that both the vapor pressure isotope effect and the chromatographic isotope effect are temperature dependent. For example, in adsorption chromatography of methane and deuteromethane, a normal isotope effect was observed at very low temperatures, a co-elution at about 133 K, and at higher temperatures an inverse isotope effect was found [31].…”

Section: Isotope Effectmentioning

confidence: 99%