Mechanism of field-flow fractionation of particles greater than \(\pu{1 \upmu\!m}\) in diameter relying on hydrodynamic lift forces near the channel wall to move particles into faster flowing streams.
Notes: - HyFFF is a preferred alternative to steric field-flow fractionation. The retention of particles larger than \(\pu{1 \upmu\!m}\) typically increases with flow rate. Particles are driven away from the wall by a hydrody-namic lift force and elevated into faster flow streams. The particles form thin layers at an equilibrium position, where the external field is balanced by the opposing hydrodynamic lift force, as compared to steric mode, where the thin layer of particles is adjacent to the accumulation wall.
- Due to the large size of the particles, Brownian diffusion away from the accumulation wall is assumed to be negligible in this mode.
Source:
PAC, 2017, 90, 181. 'Terminology of separation methods (IUPAC Recommendations 2017)' on page 221 (https://doi.org/10.1515/pac-2017-0111)