Mechanistic Study of Electrical Field Flow Fractionation. 1. Nature of the Internal Field

Palkar, Saurabh A.; Schure, Mark R.

doi:10.1021/ac9700134

Cited by 38 publications

(67 citation statements)

References 12 publications

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“…All of the theoretical analysis so far assumes that all of the applied electric field in a CyElFFF system is effective in moving particles inside the channel, which is not true due to shielding of the applied field by the electrical double layer developed at the electrode-carrier interface [10,11]. Thus, CyElFFF models based on these equations lead to poor prediction of elution times.…”

Section: Assumptions and Backgroundmentioning

confidence: 99%

Improved theory of cyclical electrical field flow fractionation

2006

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Previously reported theories for cyclical electrical field flow fractionation (CyElFFF) are severely limited in that they do not account for diffusion, steric, or electric double layer effects. Experiments have shown that these theories overpredict the retention of particles in CyElFFF. In this work, we present a model for prediction of steric, diffusion, and electrical effects. The electrical double layer effects are treated using a lumped electrical circuit model that accounts for the field shielding by the electrical double layer formed at the electrode-carrier interface. The electrical effects are shown to dominate retention times and outweigh the contributions of diffusion and particle size. Detailed results from the simulations are presented in this work, and a comparison between the theoretical and experimental results obtained from the retentions of polystyrene particle standards is presented in this paper. The models are shown to correctly predict the retention of the polystyrene standards in CyElFFF with a reasonable error, while existing models are shown to have significant failings.

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Section: Assumptions and Backgroundmentioning

confidence: 99%

Improved theory of cyclical electrical field flow fractionation

2006

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“…The actual field strength is proportional to the effective voltage across the solution and it is given as (8) where V eff and E eff are the effective voltage and the effective field, respectively. Using equations (1) and (8), (9) and λ is found from (10) …”

Section: Micro Efff Theoretical Backgroundmentioning

confidence: 99%

“…(6). The electrophoretic mobility μ can be obtained from equation (9) by inserting the drift velocity caused by the electric field, U from equation (5), followed by calculation of the diffusion coefficient, D from equation (4). The effective voltage was considered to be an average 0.6% of the applied voltage in this casethe effective voltage across a channel is known to be in the range of 0.25% to 1% of the applied voltage, depending on the composition of the buffer [10,11,14].…”

Section: Zeta-potential Analysesmentioning

confidence: 99%

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ζ-Potential analyses using micro-electrical field flow fractionation with fluorescent nanoparticles

Chang

Dosev

Kennedy

2007

Sensors and Actuators B: Chemical

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Increasingly growing application of nanoparticles in biotechnology requires fast and accessible tools for their manipulation and for characterization of their colloidal properties. In this work we determine the zeta-potentials for polystyrene nanoparticles using micro electrical field flow fractionation (μ-EFFF) which is an efficient method for sorting of particles by size. The data obtained by μ-EFFF were compared to zeta potentials determined by standard capillary electrophoresis. For proof of concept, we used polystyrene nanoparticles of two different sizes, impregnated with two different fluorescent dyes. Fluorescent emission spectra were used to evaluate the particle separation in both systems. Using the theory of electrophoresis, we estimated the zeta-potentials as a function of size, dielectric permittivity, viscosity and electrophoretic mobility. The results obtained by the μ-EFFF technique were confirmed by the conventional capillary electrophoresis measurements. These results demonstrate the applicability of the μ-EFFF method not only for particle size separation but also as a simple and inexpensive tool for measurements of nanoparticles zeta potentials.

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“…So far, we have developed particle-classification techniques using electrical field flow fractionation [1][2][3] and beads mill dispersion. Bead mills have been widely used for the dispersion of particles in suspension 4) .…”

Section: Introductionmentioning

confidence: 99%