Solid-state [sup 13]C NMR studies of ionic surfactants adsorbed on C-18 and C-8 silicas: Implications for micellar liquid chromatography
- Clarkson Univ., Potsdam, NY (United States). Dept. of Chemistry
- Florida State Univ., Tallahassee, FL (United States). Dept. of Chemistry
Solid-state [sup 13]C NMR spectroscopy techniques, including cross polarization (CP), magic angle spinning (MAS), and high-power proton decoupling, have been used to study the interactions of two ionic surfactants with octadecylsilica (C-18) and octylsilica (C-8) HPLC stationary phases. The two surfactants, cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS), are commonly used in micellar reversed-phase liquid chromatography (RPLC). Variable contact time CP/MAS [sup 13] C NMR data suggest that differences in selectivity between SDS and CTAB micellar RPLC are due to the differing nature of the SDS and CTAB-bonded phase association. For CTAB the association leads to a more hydrophobic bulk stationary phase, whereas SDS adsorption results in the formation of an anionic, hydrophilic surface layer. These results suggest that proper matching of surfactant monomer and bonded stationary phase is critical to ensure selective separations in micellar RPLC.
- OSTI ID:
- 7070254
- Journal Information:
- Journal of Colloid and Interface Science; (United States), Journal Name: Journal of Colloid and Interface Science; (United States) Vol. 165:2; ISSN 0021-9797; ISSN JCISA5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400105* -- Separation Procedures
ADSORPTION
CARBON 13
CARBON ISOTOPES
CHALCOGENIDES
CHROMATOGRAPHY
EVEN-ODD NUCLEI
ISOTOPES
LIGHT NUCLEI
LIQUID COLUMN CHROMATOGRAPHY
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PERFORMANCE
RESONANCE
SEPARATION PROCESSES
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SORPTIVE PROPERTIES
STABLE ISOTOPES
SURFACE PROPERTIES
SURFACTANTS