Hydrodynamic flow and electroosmotic flow in zirconia-packed capillaries.
Fused-silica capillaries were packed with Zirchrom-PBD stationary phase for application in CEC, nanoLC and pseudoelectrochromatography (PEC). Acido-basic properties of zirconia can be used to control the EOF even if the zirconia particles were coated by polybutadiene. As for native zirconia, the EOF is pH-dependent and the pI is close to pH 5. The mixed-mode pressure-voltage technique induced a modulation of the mobile-phase velocity as well as an electrophoretic migration of the solutes in order to improve the resolution of the separation. A significant increase of the flow appeared when both hydrodynamic and EOFs were in the same direction. But an important reduction of the electroosmotic velocity was observed when the hydrodynamic flow and EOF were opposed in Zirchrom-PBD columns. This behaviour has been observed at high or low pH on several columns. Separations of neutral and charged compounds have been performed with these columns in PEC mode.
Laboratoire des Sciences et Stratégies Analytiques, Villeurbanne, France.
Myriam
M
Crosnier de Bellaistre
Jérôme
J
Randon
Jean-Louis
JL
Rocca
D002845:Chromatography / Q000379:methods; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009995:Osmosis; D012212:Rheology; D015040:Zirconium / Q000737:chemistry*
D015040:Zirconium; C028541:zirconium oxide