Design of an open-tubular column liquid chromatograph using silicon chip technology

Manz, Andreas; Miyahara, Yutaka; Miura, Junkichi; Watanabe, Yoshio; Miyagi, Hiroyuki; Satô, Kiyoshi

doi:10.1016/0925-4005(90)80210-q

Cited by 326 publications

(179 citation statements)

References 5 publications

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“…As silicon has excellent mechanical properties and chemical inertness, it is not surprising that the introduction of micro total analysis systems (m-TAS) started with silicon-based microfluidic chips [60,61]. The steps of standard one-mask microfabrication are shown in Fig.…”

Section: Photolithographymentioning

confidence: 99%

New advances in microchip fabrication for electrochromatography

Szekeres

Guttman

2005

Electrophoresis

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There is a great demand in separation technologies for faster and more effective analysis processes. Miniaturization is a suitable technique for satisfying this demand as reduction in size gives increased separation speed with higher efficiency. CEC is an electric-field-mediated separation technique where the liquid flow is generated by the electric field itself. The main advantage of using electric field over pressure for flow generation is the flat flow profile of the EOF; thus, CEC is one of the best candidates to construct a novel and high-efficiency microanalytical device. The aim of the present paper is to review the basic fabrication and bonding principles, as well as connection and system integration options for microfluidics-based electrochromatography. The physical structure and fluidic channel formation are critically evaluated, including glass microstructuring and fusion bonding. Recent developments in nanoflow measurements and the application of various flow control units are also extensively discussed.

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Section: Photolithographymentioning

confidence: 99%

New advances in microchip fabrication for electrochromatography

Szekeres

Guttman

2005

Electrophoresis

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“…The electric coupling of the high voltage necessary for the electrophoretic separation and the low electric signals used for the electrochemical detection has been a major technological hurdle and has limited the wider development and applications of electrochemical detection. Conductivity detection was one of the main electrochemical detection methods investigated in micro-TAS [9][10][11][12][13][14][15][16][17][18][19]. Both for end-of-column and for in-column conductivity measurements, electric-coupling may cause polarization at the sensing electrodes, bubble generation, or damage to the detection circuit.…”

Section: Introductionmentioning

confidence: 99%

On‐column conductivity detection in capillary‐chip electrophoresis

Fang

Josserand

2007

Electrophoresis

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On-column conductivity detection in capillary-chip electrophoresis was achieved by actively coupling the high electric field with two sensing electrodes connected to the main capillary channel through two side detection channels. The principle of this concept was demonstrated by using a glass chip with a separation channel incorporating two double-Ts. One double-T was used for sample introduction, and the other for detection. The two electrophoresis electrodes apply the high voltage and provide the current, and the two sensing electrodes connected to the separation channel through the second double-T and probe a potential difference. This potential difference is directly related to the local resistance or the conductivity of the solution defined by the two side channels on the main separation channel. A detection limit of 15 mM (600 ppb or 900 fg) was achieved for potassium ion in a 2 mM Tris-HCl buffer (pH 8.7) with a linear range of 2 orders of magnitude without any stacking. The proposed detection method avoids integrating the sensing electrodes directly within the separation channel and prevents any direct contact of the electrodes with the sample. The baseline signal can also be used for online monitoring of the electric field strength and electroosmosis mobility characterization in the separation channel.

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“…The gas precursors used for deep etching of glass are SF 6 72 Additional gases such as He, H 2 , O 2 , or Ar may be added to control chamber pressure or for improving the quality of the etching process. Since the selectivity of the etching process is low, a relatively thick masking layer is required, such as electroplated Ni (20 lm-thick) for SF 6 chemistry, bulk silicon, 71 PECVD amorphous silicon (12 lm-thick), 70 or even a thick layer of SU-8 photoresist. 70 The selectivity of the etching rate (glass/mask) is about 4:1 and 2.5:1 for Si and SU-8 masks, respectively.…”

Section: Dry Etchingmentioning

confidence: 99%

A practical guide for the fabrication of microfluidic devices using glass and silicon

Iliescu¹,

Taylor²,

Avram³

et al. 2012

Biomicrofluidics

311

207

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This paper describes the main protocols that are used for fabricating microfluidic devices from glass and silicon. Methods for micropatterning glass and silicon are surveyed, and their limitations are discussed. Bonding methods that can be used for joining these materials are summarized and key process parameters are indicated. The paper also outlines techniques for forming electrical connections between microfluidic devices and external circuits. A framework is proposed for the synthesis of a complete glass/silicon device fabrication flow. I. WHY USE SILICON AND GLASS IN MICRO-AND NANO-FLUIDIC APPLICATIONS?Micro-and nano-fluidic technology continues to be embraced by biologists, 1-3 chemists, 4 and engineers throughout academia and industry. As its applications have expanded, there has been an explosion in the range of materials and processes used to fabricate these devices. The earliest microfluidic devices (e.g., gas 5 and liquid 6 chromatography devices) were made from silicon and glass and borrowed processes directly from semiconductor and microelectromechanical systems (MEMS) manufacturing. 7 Now, however, many researchers have moved away from silicon and glass, and instead use cast elastomers such as polydimethylsiloxane (PDMS)-which is ideal for swift prototyping-or thermoplastic polymers, which can be hot-embossed or injection-molded and are well suited to inexpensive manufacturing. Yet, there remain many applications where glass and silicon offer advantages over polymeric materials. In this paper, we highlight these advantages and offer a framework for selecting fabrication processes when using silicon and glass. A. The dominance of soft lithographyOver the last decade, PDMS has become virtually the default material for forming microfluidic devices, 8 because of the sheer ease with which it can be cast on to a micro-scale mould and then strongly bonded to glass. 9 The elastomeric nature of the material has been exploited to integrate fluidic valves and pumps on-chip and has simplified the production of multi-layer devices because the soft layers readily conform to each other. 10,11 Yet, the low stiffness (usually <1 MPa) of PDMS relative to amorphous thermoplastics, silicon, and glass has its own a) Authors to whom correspondence should be addressed. Electronic addresses: ciliescu@ibn.a-star.edu.sg and hkt@ntu.edu.sg. 6, 016505 (2012) drawbacks. High aspect-ratio channels are notoriously difficult to fabricate in PDMS because of their propensity to collapse. 12 Moreover, difficulties in automating the handling of such a soft material have hampered efforts to scale up PDMS device manufacturing. Meanwhile, PDMS's high oxygen and water permeabilities have proved both a blessing and a curse in different applications.The hydrophobic nature of PDMS can be an important consideration for some biological applications. In drug screening applications, for example, hydrophobic drugs as well as metabolites (urea or albumin) can be absorbed into the device's material due to hydrophobic--hydrophobic interaction...

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Design of an open-tubular column liquid chromatograph using silicon chip technology

Cited by 326 publications

References 5 publications

New advances in microchip fabrication for electrochromatography

New advances in microchip fabrication for electrochromatography

On‐column conductivity detection in capillary‐chip electrophoresis

A practical guide for the fabrication of microfluidic devices using glass and silicon

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