Design and implementation of injector/distributor structures for microfabricated non-porous pillar columns for capillary electrochromatography

• Published in: Journal of Chromatography A 2013-05, Vol.1289, p.80-87
• Main Authors: Sukas, Sertan, Desmet, Gert, Gardeniers, Han J.G.E.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Capillary electrochromatography; Chemistry; Chromatographic methods and physical methods associated with chromatography; chromatography; coumarin; equipment performance; Exact sciences and technology; experimental design; Flow distributor; foil; Microchannel injector; Microchip electrochromatography; Microfabricated columns; Other chromatographic methods; Pillar columns; porosity
• ISSN: 0021-9673
• DOI: 10.1016/j.chroma.2013.03.011

•We present a new approach for designing injectors/distributors for pillar columns.•A novel foil definition was applied to define the geometry.•Injection experiments and mobility measurements are reported.•Proposed design yields perfectly flat profile with enhanced concentration.•A Coumarin dyes mixture is separated in less than 80s with base-line resolution. A previously proposed foil definition is applied in the design of injector/distributor structures for solid microfabricated column structures for capillary electrochromatography. In addition to a typical bifurcated distributor, an optimized design alternative with two different configurations is experimentally evaluated. Optimized designs yielded a flat profile for the injected sample with a maximum of 3% variation from the mean width, while it went up to 18% for the typical bifurcated distributor. The implemented electrokinetic injection approach enabled controlling the volume of the injected sample accurately without sacrificing the compactness of the device design. The width of the injected sample was directly proportional to the injection time, namely 165 and 218μm base widths were obtained for 0.6 and 0.8s of feeding, respectively. Reducing the external porosity of the distributor by 85% compared to the typical design, optimized distributors caused a decrease in the mean flow velocity of up to 70%. However, having a flat initial plug shape enabled the separation of a mixture of Coumarin 440, 460, 480 and 540 at 1mm downstream of the injection point in 80s, while it was even not possible to detect the C440 signal for a typical bifurcated design.