Characterization of electrophoretic sample injection and separation in a gel-filled cyclic planar microstructure

Abstract

The data presented in this paper demonstrate that it is possible to fill a cyclic micrometer‐dimensional channel system formed in untreated glass with an acrylamide solution, to produce a gel matrix consisting of linear, noncrosslinked polyacrylamide (LPA) and to perform highly reproducible capillary gel electrophoretic separations with submicrometer plate heights within a few seconds. In such a system, no fluid flows are present and mass transport is based upon electrophoresis and diffusion only. Using a video system, an 8% LPA matrix and fluorescein isothiocyanate labelled amino acids as test compounds, sample introduction and separation could be visualized and volume‐defined, unbiased electroinjection from a 12 pL intersection of two channels via application of counter voltages could be optimized. Using laser‐induced fluorescence solute detection, the cyclic gel‐filled microstructure is shown to permit stable cyclic operation, an effective approach which simulates longer capillaries with improved separations at relatively low voltages. Furthermore, employing fluorescent phosphorothioate anti‐sense oligonucleotides, a 10% LPA matrix is demonstrated to be able to sieve and thereby separate oligonucleotides comprising more than five bases. © 1996 John Wiley & Sons, Inc.

Integrated Capillary Electrophoresis for Chemical Analysis

“…SCCE with the structure shown in Figure 6.12 has been performed in free electrolyte on¯uorescein [46]; with a modi®ed chip design micellar separations on a mixture of FITC labeled amino acids [48], and polyacylmide gel electrophoresis on oligonucleotides with base lengths of 2 to 10 bases [49] have been carried out. In Figure 6.19, the separation of FITC labeled amino acids over two cycles is shown.…”

“…This is due to leakage of the sample into the waste channels each time a corner of the structure is passed by the sample. With a different channel intersection layout and suitable countervoltages, this can be avoided [48,49]. In these examples, SCCE is used in a sensor-like fashion for analyzing a single component.…”

“…The main problem of this design is a signi®cant loss of material at the channel intersections after ®ve to ten cycles, which leads to a signal decrease. With the advanced design by Burggraf, having T-shaped channel intersections, these losses could be reduced [48,49]. …”

Lab-on-a-chip fluorescence detection with image sensor and software-based image conditioning

“…Both substrates together with glass reservoirs are bonded in one process by the use of high temperature direct bonding. After fabrication, the microchannels are filled with 10% polyakryloamid gel according to procedure proposed by von Heeren'a [23].…”

Holographic refractive index detector for application in microchip-based separation systems

“…These include capillary electrophoresis (CE), [3][4][5][6] free-flow electrophoresis, 7,8 open-channel electrochromatography, 9,10 openchannel liquid chromatography, [11][12][13] gas chromatography, 14 micellar electrokinetic capillary chromatography 15,16 and synchronized cyclic capillary electrophoresis (SCCE). [17][18][19] The adaptation of conventional detection protocols to measurement in small volumes has closely accompanied the development of m-TAS. Indeed, it has long been realized that size limits for m-TAS are primarily set by the system detector.…”