Asymmetrical Flow Field-Flow Fractionation

The most universall method under the FFF-Techniques

The field flow fractionation (FFF) is a family of analytical techniques, which use a common separation mechanism. The common separation mechanism consists of a parabolic flow rate profile in which particles or molecules are arranged in different heights of this profile by a force perpendicular to the laminar flow. The parabolic flow rate profile of all FFF variants is produced in a thin channel. Different particles or molecules are eluted out of this channel at different times.


The asymmetrical flow FFF uses a permeable wall as accumulation area through which the cross flow is drained. Experiments prove that this AFFFF allows a faster and better separation than the symmetric flow FFF with two permeable walls.

Substances in a size range of 1 nm up to 100┬Ám can be separated. The AFFFF is the most universal chromatographic method for all nano sized materials. AFFFF covers a wide range of GPC applications and has no upper exclusion volume. Many separation problems which could not be successfully solved with column based methods have been successfully solved with AFFFF.


The characterisation of macromolecular material is one of the most important activities of scientists world wide. Research in this field covers materials which find applications in different disciplines, eg. in:

  • Medicine
  • Biology
  • Pharmacy
  • Agricultural sciences
  • Polymer sciences