Premium
Nonaqueous packed capillary electrokinetic chromatographic separations of large polycyclic aromatic hydrocarbons and fullerenes
Author(s) -
Whitaker Kylen W.,
Sepaniak Michael J.
Publication year - 1994
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.11501501205
Subject(s) - chemistry , electrokinetic phenomena , acetonitrile , chromatography , methylene , tetrahydrofuran , capillary action , chloride , phase (matter) , solvent , analytical chemistry (journal) , volumetric flow rate , organic chemistry , materials science , physics , quantum mechanics , composite material
Polycyclic aromatic hydrocarbons (PAH) and a fullerene mixture (C 60 /C 70 ) were separated with capillary columns (50 μm ID) packed with a reversedphase packing (octadecylsilica, 3 μm diameter) using electrokinetic pumping. Nonaqueous (acetonitrile modified with methylene chloride or tetrahydrofuran, THF) mobile phases were used for these experiments. The effects of mobile phase composition on such factors as electroosmotic flow, plate height, and capacity factor ( K ′) are reported. The less polar solvents methylene chloride and THF produced predictable reductions in K ′ when used to modify an acetonitrile mobile phase. Large amounts of the less polar modifiers (50% v/v) also resulted in a fourfold decrease in flow rate. This meant that even with a decrease in K ′, the retention time increased. Nonaqueous capillary electrokinetic chromatographic (CEC) separations gave efficiencies as high as 160000 plates/m. Use of nonaqueous mobile phases provided small currents which in turn diminished the role of heating effects on efficiency. The nonaqueous system also provided greater solubility for the hydrophobic solutes. A Van Deemter plot for an acetonitrile mobile phase was obtained that exhibited expected trends in plate height with flow rate and K ′. Solvent rinses with water and THF are shown to have only small effects on retention and flow rate.