Ionic liquids as novel stationary phases in gas liquid chromatography: Inverse or normal isotope effect?
| Autor: | Carmen Metzger, Petra Slabizki, Sabrina Müntnich, Elisa Gracia-Moreno, Hans-Georg Schmarr |
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| Rok vydání: | 2012 |
| Předmět: |
Chromatography
Gas Chromatography Dodecane Elution Organic Chemistry Chemie Analytical chemistry Ionic Liquids General Medicine Biochemistry London dispersion force Analytical Chemistry symbols.namesake chemistry.chemical_compound Isotopes Models Chemical chemistry Phase (matter) Kinetic isotope effect Ionic liquid symbols Gas chromatography Organic Chemicals van der Waals force Hydrophobic and Hydrophilic Interactions |
| Zdroj: | Journal of Chromatography A. 1270:310-317 |
| ISSN: | 0021-9673 |
| Popis: | The separation of deuterated and non-deuterated compounds in gas liquid partitioning chromatography (GLC) on silicone type stationary phase usually results in the inverse isotope effect. With ionic liquids (ILs) as stationary phase, however, this may show a totally different nature. The inverse isotope effect, in which heavier (deuterated) isotopic compounds (isotopologues) elute earlier, is to be expected when van der Waals (London) dispersion forces play a dominant role in the solute-stationary phase interaction. Such (apolar) interactions seem to play only a minor role when ILs are the stationary phases, leading to only a marginal inverse isotope effect, e.g. for the separation of 2,4,6-trichloroanisole and its [(2)H(5)]-isotopologue on 1,12-di(tripropylphosphonium) dodecane bis(trifluoromethansulfonyl) amide (commercialized as SLB-IL59, Supelco). Indeed, with the most polar stationary phase available (commercialized as SLB-IL111; Supelco), this separation showed a normal isotope effect. Further examples are presented and the nature of the isotope effect observed is discussed. |
| Databáze: | OpenAIRE |
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