Joule heating effect on electroosmotic flow and mass species transport in a microcapillary

Tang, Gongyue; Yang, Chun; Chai, John C.; Gong, Haiqing

doi:10.1016/j.ijheatmasstransfer.2003.07.006

Cited by 168 publications

(106 citation statements)

References 22 publications

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“…After obtaining the ion distribution, Navier-Stokes (NS) equation can then be solved separately to obtain the velocity field. [10][11][12] In contrast, PNP model describes the ion distribution in the liquid according to the NernstPlanck equations for positive and negative ion species…”

Section: Electroosmotic Flow Modelmentioning

confidence: 99%

Direction dependence of displacement time for two-fluid electroosmotic flow

Lim

Lam

2012

Biomicrofluidics

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Electroosmotic flow that involves one fluid displacing another fluid is commonly encountered in various microfludic applications and experiments, for example, current monitoring technique to determine zeta potential of microchannel. There is experimentally observed anomaly in such flow, namely, the displacement time is flow direction dependent, i.e., it depends if it is a high concentration fluid displacing a low concentration fluid, or vice versa. Thus, this investigation focuses on the displacement flow of two fluids with various concentration differences. The displacement time was determined experimentally with current monitoring method. It is concluded that the time required for a high concentration solution to displace a low concentration solution is smaller than the time required for a low concentration solution to displace a high concentration solution. The percentage displacement time difference increases with increasing concentration difference and independent of the length or width of the channel and the voltage applied. Hitherto, no theoretical analysis or numerical simulation has been conducted to explain this phenomenon. A numerical model based on finite element method was developed to explain the experimental observations. Simulations showed that the velocity profile and ion distribution deviate significantly from a single fluid electroosmotic flow. The distortion of ion distribution near the electrical double layer is responsible for the displacement time difference for the two different flow directions. The trends obtained from simulations agree with the experimental findings.

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Section: Electroosmotic Flow Modelmentioning

confidence: 99%

Direction dependence of displacement time for two-fluid electroosmotic flow

Lim

Lam

2012

Biomicrofluidics

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“…The problem is not only the temperature increase itself but also the formation of an undesired temperature gradient. Several groups [119][120][121] proposed numerical solutions and models to alleviate Joule heat effects on EOF and mass transport. Sweedler's group [122] followed the change by nanoliter-volume NMR thermometry and concluded that the temperature change due to the Joule heating has a significant effect on highelectric-field and large-diameter channels.…”

Section: General Considerationsmentioning

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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“…In electrophoresis, the Joule heat generates a radial temperature distribution in the liquid solution and the solid capillary wall, which exhibits a parabolic-like pattern with the centerline having the highest temperature. [15][16][17] This radial temperature distribution becomes more serious as the diameter of the separation tube increases, even under the same physicochemical conditions. 18 This unevenness can complicate the profile of the electrical conductivity, dynamic viscosity and diffusion coefficient across the electrophoresis channel.…”

Section: Resultsmentioning

confidence: 99%

Zone Electrophoresis in an Inner-cooling Wide-bore Electrophoresis System with UV Detection

et al. 2008

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Experimental Reagents and chemicalsIn this study, all chemicals used were of analytical grade or higher, unless otherwise stated. Benzenesulfonic acid, salicylic acid, p-toluenesulfonic acid, p-aminobenzene sulfonic acid, paminobenzoic acid, phenylamine, ephedrine, 1-naphthylamine, . R. ChinaA novel, high-performance wide-bore electrophoresis (WE) system with inner-cooling has been developed. By introducing the mode of a shell and tube heat exchanger into this system to remove Joule heat generated during electrophoresis, it is feasible to extend electrophoresis from the conventional capillary (i.d. <100 mm) to a wide-bore tube (i.d. >1000 mm). The wide tube allows the loading of over 1.0 mL of the sample with an LOD of 3.0 ¥ 10 -4 mg/mL (signal-to-noise ratio, 3:1). Satisfactory separations of model compounds have been achieved on the WE system.

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Joule heating effect on electroosmotic flow and mass species transport in a microcapillary

Cited by 168 publications

References 22 publications

Direction dependence of displacement time for two-fluid electroosmotic flow

Direction dependence of displacement time for two-fluid electroosmotic flow

New advances in microchip fabrication for electrochromatography

Zone Electrophoresis in an Inner-cooling Wide-bore Electrophoresis System with UV Detection

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