Size separation of supermicrometer particles in asymmetrical flow field-flow fractionation. Flow conditions for rapid elution

The performance of lift-hyperlayer asymmetrical flow field-flow fractionation using rapid elution conditions was tested through the separation of standard polystyrene latex particles of diameters from 2 to 20 mum. Optimization of flowrates was studied not only in order to obtain efficient and rapid separation; but also to work under conditions of various shape and steepness of the axial flow velocity gradient. Using extreme flow conditions, the five widely spaced particle sizes, 20.5-, 15.0-, 9.7-, 5.0-, and 2.0-mum diameter, could be resolved in 6 min, whereas for the narrower size range of 20.5-5.0 mum, 1 min was enough. The size selectivity in the size range 9.7-2.0 mum was studied as a function of flowrates and particle size and was found to be constant. A particle trapping device made it possible to separate particles of sizes >10 mum; which has previously proven to be difficult in asymmetrical channels.