Criteria for successful separation by continuous electrophoresis and electrochromatography in blocks and columns

Ravoo, Edo; Gellings, P.J.; Vermeulen, Th.

doi:10.1016/s0003-2670(01)80581-x

Cited by 4 publications

(4 citation statements)

References 2 publications

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“…Joule heating broadening 29,30 (d) Joule heating distortions were found to have an insignificant contribution to the theoretical variance. The µ-FFE device has a very narrow separation bed depth (50 µm), which facilitates efficient cooling and therefore minimizes any Joule heating effects.…”

Section: Resultsmentioning

confidence: 93%

“…Included in the plot are the theoretical variances (solid lines) calculated using eq 2, assuming band broadening contributions from the initial bandwidth, diffusion, hydrodynamic broadening, Joule heating distortion, and adsorption. 19,[29][30][31][32] In eqs 2a-e, w i is the initial plug width (cm) [w i ) 0.038 cm], D is the solute diffusion coefficient (cm 2 /s) [D HSA ) 6.1 × 10 -7 , D Brad ) 1.0 × 10 -6 , and D Ribo A ) 1.07 × 10 -6 cm 2 /s], x center is the migration distance for a species at the center of the separation bed (cm), x marginal is the migration distance for a species at some radial position, z, from the center of the separation bed (cm), r is half the bed depth (cm), ∆T is the temperature difference between the buffer solution and the separation bed wall (°C), κ is the carrier buffer conductivity (Ω -1 cm -1 ), λ is the thermal conductivity (W cm -1 °C-1 ), ν is the solute velocity (cm/s), K d is the first-order dissociation constant (s -1 ), and k′ is the capacity factor. The remaining terms have their usual meanings.…”

Section: Resultsmentioning

confidence: 99%

“…Figure is a plot of the experimental variances for HSA, bradykinin, and ribonuclease A as a function of the field strength. Included in the plot are the theoretical variances (solid lines) calculated using eq 2, assuming band broadening contributions from the initial bandwidth, diffusion, hydrodynamic broadening, Joule heating distortion, and adsorption. ,− …”

Section: Resultsmentioning

confidence: 99%

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Continuous Separation of High Molecular Weight Compounds Using a Microliter Volume Free-Flow Electrophoresis Microstructure

1996

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A microliter volume free-flow electrophoresis microstructure (μ-FFE) was used to perform a continuous separation of high molecular weight compounds. The μ-FFE microstructure had a separation bed volume of 25 μL and was fabricated from silicon using standard micromachining technology. Laser-induced fluorescence was used to detect the sample components, which were labeled with fluorescein isothiocyanate (FITC) prior to analysis. The continuous separation of human serum albumin (HSA), bradykinin, and ribonuclease A demonstrated that only 25 V/cm was required to isolate HSA from bradykinin and ribonuclease A, while 100 V/cm was needed for the separation of bradykinin from ribonuclease A. Comparison of the observed band broadening with the theoretical variance indicated that dispersion due to the initial bandwidth, diffusion, and hydrodynamic broadening were the main contributors to the band broadening of HSA and bradykinin. However, the band broadening for ribonuclease A could not be sufficiently accounted for using the above contributors. Adsorption was found to be a possible contributor to the overall variance for ribonuclease A. Calculation of the theoretical variance due to Joule heating indicated that broadening due to Joule heating effects was insignificant. This was likely due to the narrow cross-sectional area of the device, which facilitated efficient cooling. Electrohydrodynamic distortion was observed for HSA as it migrated toward the side bed. Studies of the resolution of bradykinin and ribonuclease A as a function of field strength at various sample and carrier flow rates indicated that, for maximum throughput, high field strengths and high flow rates were required. However, no optimal conditions were found. The μ-FFE device has a peak capacity of ∼8 bands/cm, while for a typical separation of proteins using a commercial system, a peak capacity of 10 bands/cm is obtained. Thus, the resolving power of the μ-FFE device is similar to those of conventional systems. The continuous separation of tryptic digests of mellitin and cytochrome c demonstrated the ability to continuously separate more complex mixtures. Finally, modifications were made to the microstructure to facilitate fraction collection, and the fractionation of whole rat plasma was performed. Off-line analysis of the resulting fractions indicated that the complete isolation of serum albumin and globulins was possible using a field strength of 25 V/cm.

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Continuous Separation of High Molecular Weight Compounds Using a Microliter Volume Free-Flow Electrophoresis Microstructure

1996

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“…The equations for mass transport and heat transfer are ∂ c ∂ t = − ∂ v x c ∂ x − ∂ v y c ∂ y + ∂ ∂ x D ∂ c ∂ x + ∂ ∂ y D ∂ c ∂ y + ∂ ∂ z D ∂ c ∂ z λ true( ∂ 2 T ∂ x 2 + ∂ 2 T ∂ z 2 true) − ρ C p ∂ T ∂ t + κ E 2 = 0 where c is the molecular concentration, t is the time, ν x and ν y are the x and y components of the resultant velocity, D is the diffusion coefficient and, finally, λ, T , ρ, C p , and κ are the thermal conductivity, temperature, density, specific heat capacity, and electrical conductivity of the electrolyte. To obtain expressions for the lateral separation, Δ x , and widths of the separated streams, w , we solved eq…”

Section: Resultsmentioning

confidence: 99%

Non-Orthogonal-to-the-Flow Electric Field Improves Resolution in the Orthogonal Direction: Hidden Reserves for Combining Synthesis and Purification in Continuous Flow

2010

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There is a pressing need for continuous purification of products of synthesis conducted in continuous-flow microreactors. An existing technique, micro free-flow electrophoresis (microFFE), could fulfill this niche if its resolving power for similar molecules was improved. MicroFFE continuously separates ions in the hydrodynamic flow by an electric field orthogonal to the flow. Here, we prove theoretically from first principles that the resolving power of microFFE can be greatly improved by the use of a nonorthogonal to the flow field. This result may be decisive in starting practical attempts to combine synthesis in continuous-flow microreactors with continuous-flow purification by microFFE.

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Non-orthogonal micro-free flow electrophoresis: From theory to design concept

Evenhuis¹,

Okhonin²,

Krylov³

2010

Analytica Chimica Acta

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Criteria for successful separation by continuous electrophoresis and electrochromatography in blocks and columns

Cited by 4 publications

References 2 publications

Continuous Separation of High Molecular Weight Compounds Using a Microliter Volume Free-Flow Electrophoresis Microstructure

Continuous Separation of High Molecular Weight Compounds Using a Microliter Volume Free-Flow Electrophoresis Microstructure

Non-Orthogonal-to-the-Flow Electric Field Improves Resolution in the Orthogonal Direction: Hidden Reserves for Combining Synthesis and Purification in Continuous Flow

Non-orthogonal micro-free flow electrophoresis: From theory to design concept

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