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Predicting ion concentration polarization and analyte stacking/focusing at nanofluidic interfaces
Author(s) -
FloresGalicia Fatima,
Eden Alexander,
Pallandre Antoine,
Pennathur Sumita,
HaghiriGosnet AnneMarie
Publication year - 2022
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.202100297
Subject(s) - electrokinetic phenomena , microchannel , stacking , concentration polarization , electrolyte , analyte , electric field , nanofluidics , polarization (electrochemistry) , ion , surface charge , streaming current , materials science , chemical physics , poisson's equation , analytical chemistry (journal) , nanotechnology , optoelectronics , chemistry , physics , electrode , chromatography , biochemistry , organic chemistry , quantum mechanics , membrane
Abstract We report on the investigation of electropreconcentration phenomena in micro‐/nanofluidic devices integrating 100 μm long nanochannels using 2D COMSOL simulations based on the coupled Poisson–Nernst–Planck and Navier–Stokes system of equations. Our numerical model is used to demonstrate the influence of key governing parameters such as electrolyte concentration, surface charge density, and applied axial electric field on ion concentration polarization (ICP) dynamics in our system. Under sufficiently extreme surface‐charge‐governed transport conditions, ICP propagation is shown to enable various transient and stationary stacking and counter‐flow gradient focusing mechanisms of anionic analytes. We resolve these spatiotemporal dynamics of analytes and electrolyte ICP over disparate time and length scales, and confirm previous findings that the greatest enhancement is observed when a system is tuned for analyte focusing at the charge, excluding microchannel, nanochannel electrical double layer (EDL) interface. Moreover, we demonstrate that such tuning can readily be achieved by including additional nanochannels oriented parallel to the electric field between two microchannels, effectively increasing the overall perm‐selectivity and leading to enhanced focusing at the EDL interfaces. This approach shows promise in providing added control over the extent of ICP in electrokinetic systems, particularly under circumstances in which relatively weak ICP effects are observed using only a single channel.