Miniaturization of capillary electrophoresis systems using micromachining techniques

Campaña, Ana Ma García; Baeyens, Willy R. G.; Aboul‐Enein, Hassan Y.; Zhang, Xinrong

doi:10.1002/(sici)1520-667x(1998)10:4<339::aid-mcs4>3.0.co;2-h

Cited by 15 publications

(5 citation statements)

References 63 publications

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“…The bead velocity was also seen to increase with J. Maximum observed velocities were 1 mm s 21 for a magnetic field intensity of 0.42 T and a current density of 4000 A m 22 . Measured velocities were on the same order of magnitude as theory.…”

Section: Resultsmentioning

confidence: 86%

“…4. The current density begins to deviate from linearity after 2500 A m 22 . This shows that Joule heating may affect our measurements of MHD bead velocities above this current density threshold for an applied voltage of 15 V with such a buffer solution.…”

Section: Joule Heating and Power Dissipationmentioning

confidence: 99%

“…In microfluidic systems, Joule heating was observed to occur for Q d values 22 larger than 3 W m 21 (instead of 1 W m 21 for standard capillaries). With our specific geometry, the power dissipation threshold corresponding to the beginning of Joule heating is seen at 2.5 W m 21 .…”

Section: Joule Heating and Power Dissipationmentioning

confidence: 99%

“…Comparison between theoretical maximum MHD flow velocity and measured maximum bead velocities (current density of 2083 A m22 , citrate phosphate buffer with KCl added for fixed ionic strength)…”

mentioning

confidence: 99%

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A high current density DC magnetohydrodynamic (MHD) micropump

et al. 2005

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This paper describes the working principle of a DC magnetohydrodynamic (MHD) micropump that can be operated at high DC current densities (J) in 75-microm-deep microfluidic channels without introducing gas bubbles into the pumping channel. The main design feature for current generation is a micromachined frit-like structure that connects the pumping channel to side reservoirs, where platinum electrodes are located. Current densities up to 4000 A m(-2) could be obtained without noticeable Joule heating in the system. The pump performance was studied as a function of current density and magnetic field intensity, as well as buffer ionic strength and pH. Bead velocities of up to 1 mm s(-1) (0.5 microL min(-1)) were observed in buffered solutions using a 0.4 T NdFeB permanent magnet, at an applied current density of 4000 A m(-2). This pump is intended for transport of electrolyte solutions having a relatively high ionic strength (0.5-1 M) in a DC magnetic field environment. The application of this pump for the study of biological samples in a miniaturized total analysis system (microTAS) with integrated NMR detection is foreseen. In the 7 T NMR environment, a minimum 16-fold increase in volumetric flow rate for a given applied current density is expected.

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Section: Resultsmentioning

confidence: 86%

Section: Joule Heating and Power Dissipationmentioning

confidence: 99%

Section: Joule Heating and Power Dissipationmentioning

confidence: 99%

mentioning

confidence: 99%

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A high current density DC magnetohydrodynamic (MHD) micropump

et al. 2005

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“…There are a number of techniques routinely used to fabricate microfluidic devices. Examples include, moulding [53][54][55][56][57][58], injection moulding [59][60][61], hot embossing [11,62], micromachining [63], milling [42,64,65] and screen printing [53,66].…”

Section: Typical Fabrication Methods For Microfluidic Chipsmentioning

confidence: 99%

Review on the development of truly portable andin-situcapillary electrophoresis systems

Lewis

Cranny

Harris

et al. 2013

Meas. Sci. Technol.

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Capillary electrophoresis (CE) is a technique which uses an electric field to separate a mixed sample into its constituents. Portable CE systems enable this powerful analysis technique to be used in the field. Many of the challenges for portable systems are similar to those of autonomous in-situ analysis and therefore portable systems may be considered a stepping stone towards autonomous in-situ analysis. CE is widely used for biological and chemical analysis and example applications include: water quality analysis; drug development and quality control; proteomics and DNA analysis; counter-terrorism (explosive material identification) and corrosion monitoring. The technique is often limited to laboratory use, since it requires large electric fields, sensitive detection systems and fluidic control systems. All of these place restrictions in terms of: size, weight, cost, choice of operating solutions, choice of fabrication materials, electrical power and lifetime. In this review we bring together and critique the work by researchers addressing these issues. We emphasize the importance of a holistic approach for portable and in-situ CE systems and discuss all the aspects of the design. We identify gaps in the literature which require attention for the realization of both truly portable and in-situ CE systems.

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Towards stationary phases for chromatography on a microchip: Molded porous polymer monoliths prepared in capillaries by photoinitiatedin situ polymerization as separation media for electrochromatography

2000

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Photoinitiated free radical polymerization has been used for the preparation of porous polymer monoliths within UV transparent fused silica capillaries and quartz tubes. These formats were used as models for the preparation of the separation media within channels of microfabricated devices. A mixture of ethylene dimethacrylate, butyl methacrylate, and 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid was polymerized in the presence of a porogenic solvent consisting of 1‐propanol, 1,4‐butanediol, and water at room temperature under UV irradiation. Modification of the porogen composition enables the tailoring of pore size within the broad range from ca. 100 to 4000 nm. Scanning electron micrographs confirmed the homogeneity of the porous structure of the materials prepared, even in a quartz tube with a diameter as large as 4 mm. Separation properties of the resulting capillary columns were tested in capillary electrochromatography (CEC) mode using a mixture of thiourea and eight aromatic compounds. Plate number as high as 210 000 plates/m were found for a capillary column with optimized porous properties. The monolithic columns were also able to separate mixtures of peptides.

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Miniaturization of capillary electrophoresis systems using micromachining techniques

Cited by 15 publications

References 63 publications

A high current density DC magnetohydrodynamic (MHD) micropump

A high current density DC magnetohydrodynamic (MHD) micropump

Review on the development of truly portable andin-situcapillary electrophoresis systems

Towards stationary phases for chromatography on a microchip: Molded porous polymer monoliths prepared in capillaries by photoinitiatedin situ polymerization as separation media for electrochromatography

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