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Discussion.

Wahlund Karl-Gustav1

  • 1Professor Karl-Gustav Wahlund, Centre for Analysis and Synthesis, P.O. Box 118, SE-22100 LUND, Sweden.

Journal of Chromatography. A
|June 9, 2020
PubMed
Summary

This study critically reviews asymmetrical flow field-flow fractionation (AF4), questioning experimental definitions and conclusions. Theoretical analysis supports constant cross-flow velocity, contradicting claims of "fingering" causing band broadening in AF4 separations.

Area of Science:

  • Analytical Chemistry
  • Separation Science

Background:

  • Asymmetrical flow field-flow fractionation (AF4) is a technique used for separating macromolecules.
  • Previous studies have investigated the focusing position in AF4, but some findings require clarification.

Purpose of the Study:

  • To critically evaluate the theoretical and experimental findings regarding the focusing position in asymmetrical flow field-flow fractionation (AF4).
  • To address questionable statements and experimental definitions in a recent publication on AF4.

Main Methods:

  • Theoretical analysis of cross-flow velocity constancy along the AF4 channel.
  • Review and critique of experimental methodologies for measuring focusing position.
  • Comparison of theoretical predictions with existing literature data.
Keywords:
Asymmetrical flow field-flow fractionationField-flow fractionation

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Main Results:

  • The assumption of constant cross-flow velocity in AF4 channels is theoretically valid and supported by literature.
  • Experimental procedures for measuring focusing position in the discussed study were not adequately defined.
  • Claims linking "fingering" of focused blue dextran to band broadening are contradicted by theoretical and experimental evidence.

Conclusions:

  • The theoretical framework for AF4 focusing position is robust, with constant cross-flow velocity being a valid assumption.
  • Further refinement of experimental designs is necessary for accurate AF4 focusing position measurements.
  • The "fingering" phenomenon does not significantly contribute to band broadening in the context of AF4 separations.