Integrated Capillary Electrophoresis Devices with an Efficient Postcolumn Reactor in Planar Quartz and Glass Chips

Abstract

Methods to fabricate planar capillary electrophoresis devices integrated with a postcolumn reactor in fused silica (quartz) and Pyrex glass are presented. Quartz is etched at ∼1 μm/min with a 2.1:1 width-to-depth ratio using a Cr/Au/Cr metal mask and concentrated HF/HNO(3). On-chip postcolumn reaction of o-phthaldialdehyde (OPA) and amino acids gave theoretical plate numbers up to 83 000 and ∼90 ms peak widths, corresponding to 14 plates/V and a 0.5 μm theoretical plate height. The reactor geometry caused only a 10% degradation in efficiency.

New advances in microchip fabrication for electrochromatography

“…Structures on glass substrate are most commonly generated by standard photolithographic techniques. The basic manufacturing steps are the same as for silicon except the Cr/Au protective layer (the mask) representing a significant difference usually applied for glass [13,[22][23][24][25], where chrome is applied to enhance the adhesion of gold to the glass surface. Gold was found to be an efficient protective material for most glass-etching materials.…”

Integration of a flow-type chemiluminescence detector on a glass electrophoresis chip

“…Therefore, this configuration is clearly unsuitable for an application that requires the injection of larger sample plugs to enhance detection sensitivity, which is largely dependent on the volume of sample solution. A more appropriate solution is to replace the cross-channel arrangement with double-T form [28]. This geometry allows for high-efficiency sample injections and geometric definition of sample plug size, irrespective of injector loading times or the applied injection potentials [28,29].…”

“…A more appropriate solution is to replace the cross-channel arrangement with double-T form [28]. This geometry allows for high-efficiency sample injections and geometric definition of sample plug size, irrespective of injector loading times or the applied injection potentials [28,29]. The injected volume with the double-T-form injection system is determined by the double-T's length and always larger than that with the cross-injection system [25].…”

Fluorometric Determination of Sulfite and Nitrite in Aqueous Samples Using a Novel Detection Unit of a Microfluidic Device

“…In analytical chemistry, a micro-total analysis system (µ-TAS) 1,2 and a lab-on-a-chip concept, 3 which is based on a micro-fluidic channel chip, have been developed as new tools. Microchip devices with miniaturized electrophoresis for high-speed analysis were applied to the determination of DNA fragments, [4][5][6] amino acids, [7][8][9] proteins, [10][11][12][13] and so forth. Moreover, integration of the analysis system is also an advantage of the microchip, for example, with cell analysis, [14][15][16] enzymatic reactions, [17][18][19] and biochemical reactions.…”