Submicrometer plate heights for capillaries packed with silica colloidal crystals.
Extremely uniform packing of colloidal silica in capillaries is shown. Reversed-phase electrochromatograms of DiI-C(12) exhibit plate heights as low as 0.23 microm and a reduced plate height as low as 0.7, using 75 microm i.d. capillaries packed with 330 nm silica particles. The contribution from the A term is 0 +/- 20 nm in electrochromatography. The particles are shown to form colloidal crystals inside the capillaries. Optical images show Bragg diffraction, indicative of crystallinity. Scanning electron microscopy (SEM) images show face-centered cubic crystallinity, and the porosity is 0.25 +/- 0.01, which is in agreement with that for face-centered cubic crystals. The capillaries are fritless, and 100 microm i.d. capillaries packed with silica colloidal crystals withstand pressures of at least 12,400 psi.
Douglas S
DS
Malkin
Bingchuan
B
Wei
Arthur J
AJ
Fogiel
Sau Lan
SL
Staats
Mary J
MJ
Wirth
D053801:Capillary Electrochromatography; D003102:Colloids / Q000737:chemistry*; D003460:Crystallization; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*
D003102:Colloids; D012822:Silicon Dioxide