Effect of temperature gradients on the efficiency of capillary zone electrophoresis separations

Grushka, Eli; McCormick, Randy M.; Kirkland, J. J.

doi:10.1021/ac00178a011

Cited by 272 publications

(185 citation statements)

References 8 publications

(17 reference statements)

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“…In 1989, Grushka et al 16 studied the effect of temperature gradients on the efficiency of capillary electrophoresis separations. They reported that Joule heating leads to a temperature-dependent flow velocity, which causes a loss in separation efficiency at high temperature.…”

Section: Introductionmentioning

confidence: 99%

Effect of Joule heating on isoelectric focusing of proteins in a microchannel

2014

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Electric field-driven separation and purification techniques, such as isoelectric focusing (IEF) and isotachophoresis, generate heat in the system that can affect the performance of the separation process. In this study, a new mathematical model is presented for IEF that considers the temperature rise due to Joule heating. We used the model to study focusing phenomena and separation performance in a microchannel. A finite volume-based numerical technique is developed to study temperature-dependent IEF. Numerical simulation for narrow range IEF (6 < pH < 10) is performed in a straight microchannel for 100 ampholytes and two model proteins: staphylococcal nuclease and pancreatic ribonuclease. Separation results of the two proteins are obtained with and without considering the temperature rise due to Joule heating in the system for a nominal electric field of 100 V/cm. For the no Joule heating case, constant properties are used, while for the Joule heating case, temperature-dependent titration curves and thermo-physical properties are used. Our numerical results show that the temperature change due to Joule heating has a significant impact on the final focusing points of proteins, which can lower the separation performance considerably. In the absence of advection and any active cooling mechanism, the temperature increase is the highest at the midsection of a microchannel. We also found that the maximum temperature in the system is a strong function of the DpK value of the carrier ampholytes. Simulation results are also obtained for different values of applied electric fields in order to find the optimum working range considering the simulation time and buffer temperature. Moreover, the model is extended to study IEF in a straight microchip where pH is formed by supplying H þ and OH À , and the thermal analysis shows that the heat generation is negligible in ion supplied IEF. V C 2014 AIP Publishing LLC.

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Section: Introductionmentioning

confidence: 99%

Effect of Joule heating on isoelectric focusing of proteins in a microchannel

2014

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“…[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. 19 The Joule heat in a WE system can be evaluated based on…”

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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“…While microfluidic systems dissipate Joule heating effectively due to favourable surface area to volume ratios, at high electric fields heat generation can raise the temperature and generate temperature gradients in the channel. 43,44 Inclusion of a 30 to 60 s incubation step (E = 0 V cm 21 , no electromigration) during patterning of region (ii) enhanced biotinylated capture protein immobilization in the streptavidin-PA gel at the leading edge of the concentration front. During the incubation period, unbound biotinylated c100p in region (ii) diffused into region (iii), leading to a slow but sharp expansion of the interface according to a competition between reaction and diffusion.…”

Section: The Role Of Da In Control Of Interfaces Between Barcode Regionsmentioning

confidence: 99%

Microfluidic barcode assay for antibody-based confirmatory diagnostics

et al. 2013

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Confirmatory diagnostics offer high clinical sensitivity and specificity typically by assaying multiple disease biomarkers. Employed in clinical laboratory settings, such assays confirm a positive screening diagnostic result. These important multiplexed confirmatory assays require hours to complete. To address this performance gap, we introduce a simple 'single inlet, single outlet' microchannel architecture with multiplexed analyte detection capability. A streptavidin-functionalized, channel-filling polyacrylamide gel in a straight glass microchannel operates as a 3D scaffold for a purely electrophoretic yet heterogeneous immunoassay. Biotin and biotinylated capture reagents are patterned in discrete regions along the axis of the microchannel resulting in a barcode-like pattern of reagents and spacers. To characterize barcode fabrication, an empirical study of patterning behaviour was conducted across a range of electromigration and binding reaction timescales. We apply the heterogeneous barcode immunoassay to detection of human antibodies against hepatitis C virus and human immunodeficiency virus antigens. Serum was electrophoresed through the barcode patterned gel, allowing capture of antibody targets. We assess assay performance across a range of Damkohler numbers. Compared to clinical immunoblots that require 4-10 h long sample incubation steps with concomitant 8-20 h total assay durations; directed electromigration and reaction in the microfluidic barcode assay leads to a 10 min sample incubation step and a 30 min total assay duration. Further, the barcode assay reports clinically relevant sensitivity (25 ng ml 21 in 2% human sera) comparable to standard HCV confirmatory diagnostics. Given the low voltage, low power and automated operation, we see the streamlined microfluidic barcode assay as a step towards rapid confirmatory diagnostics for a low-resource clinical laboratory setting.

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Effect of temperature gradients on the efficiency of capillary zone electrophoresis separations

Cited by 272 publications

References 8 publications

Effect of Joule heating on isoelectric focusing of proteins in a microchannel

Effect of Joule heating on isoelectric focusing of proteins in a microchannel

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

Microfluidic barcode assay for antibody-based confirmatory diagnostics

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