(224c) The Continuous Chromatographic Separation of Molecules/Particles Using Optical Electric Fields

We introduce a new field-flow fractionation technique, whereby molecules are separated based on their differential interaction with optical electric fields, i.e. electric fields with frequencies in the visible and near-infrared range. When solute particles are introduced to electric field gradients they are polarized based on their size and refractive index. The resulting attractive or repulsive polarization potential influences a solute particle's lateral position with respect to the gradient in the electric field. By coupling well described optical electric fields with a non-uniform flow, we demonstrate how such potentials can be used to continuously separate nanometer scale solute particles in a flowing two dimensional microchannel. Comparisons are made between theoretical axially uniform optical fields and numerical simulations considering optical electric fields with finite width. We discuss the impact of the governing dimensionless groups on the resolution of separation and the dispersion of solute molecules after separation. An experimental apparatus is introduced and comparisons are made between theoretical and experimental results.