Surfactant coated graphitic carbon based stationary phases for anion-exchange chromatography.
Separations of common inorganic anions were carried out on three different surfactant coated media using carbonate/bicarbonate eluents with suppressed conductivity detection. Graphitic carbon columns (porous graphitic carbon and carbon-clad zirconia) packed with 3 microm particles have been converted into anion-exchange stationary phases by equilibration with the cationic surfactants: didodecyldimethylammonium bromide (DDAB); cetyltrimethylammonium bromide (CTAB); and cetylpyridinium chloride (CPC). Additionally, an ethylene-bridged silica column was studied with CPC coatings. Porous graphitic carbon (PGC) columns coated with DDAB exhibited pressure increases and loss of resolution at higher capacities. CPC coatings on PGC exhibited better repeatability and efficiencies of 5.0 x 10(4)plates/m. However, CPC coatings exhibited a 15% loss in retention factor with <1.2 x 10(3) column volumes on PGC. Conversely, the ethylene-bridged silica column showed complete failure in less than 8 h of use. As with PGC, carbon-clad zirconia coated with CPC showed an initial loss of capacity, but thereafter was stable for more than 1.7 x 10(3) column volumes (t(r) RSD<2%).
Department of Chemistry, University of Alberta, Gunning/Lemieux Chemistry Centre, Edmonton, AB, Canada T6G 2G2.
Stuart D
SD
Chambers
Charles A
CA
Lucy
D000837:Anion Exchange Resins; D002244:Carbon / Q000737:chemistry*; D002852:Chromatography, Ion Exchange / Q000295:instrumentation*; D004563:Electrochemistry; D015203:Reproducibility of Results; D013501:Surface-Active Agents / Q000737:chemistry*
D000837:Anion Exchange Resins; D013501:Surface-Active Agents; D002244:Carbon