Shape-Enhanced Open-Channel Hydrodynamic Chromatography

Abstract

Hydrodynamic chromatography (HDC) is a well-established analytical separation method for the size separation of nano-and microparticles and large molecular weight solutes such as synthetic polymers and proteins. We report on a theoretical study showing that the separation resolution of opentubular HDC can be significantly enhanced by changing the cross-sectional shape of the separation channel. By enforcing Brenner's macro-transport approach, we provide theoretical/numerical evidence showing how the shape of the cross section influences quantitatively both the selectivity and the axial dispersion of the suspended particles in HDC. The separation performance of square-, triangle-, and star-shaped channel cross sections is compared to that of a cylindrical capillary over three decades of the particle Pećlet number in terms of the minimal separation length and time to obtain the unit resolution of a two-particle mixture. Enhancement factors up to 400% are found in the case of triangular shapes, with the best performing case being the 70.6°angle, which can be obtained by KOH etching of bulk silicon.

An In-Depth Investigation of Micropillar Array Columns for the Separation of Finite-Sized Particles by Hydrodynamic Chromatography

“…The accurate estimate of the effective axial velocity U e x and dispersion coefficient D e x allows us to predict the minimum column length necessary to achieve the separation of a binary mixture. Specifically, the separation resolution R ij of a mixture of particles of two different sizes, say i and j , in a channel of length L c can be expressed as , R i j = 1 2 | L c U e x false( i false) − L c U e x false( j false) | 2 D e x false( i false) L c ( U e x false( i false) ) 3 + 2 D e x false( j false) L c ( U e x false( j false) ) 3 = f i j L c and the minimum column length MCL ij is the column length a...…”

“…The accurate estimate of the effective axial velocity U e x and dispersion coefficient D e x allows us to predict the minimum column length necessary to achieve the separation of a binary mixture. Specifically, the separation resolution R ij of a mixture of particles of two different sizes, say i and j , in a channel of length L c can be expressed as , and the minimum column length MCL ij is the column length associated with the unitary resolution R ij = 1, i.e., MCL ij = (1/ f ij ) 2 .…”

Shear dispersion of multispecies electrolyte solutions in the channel domain

“…2022) and modelling isotachophoresis (Bhattacharyya et al. 2013; Gopmandal & Bhattacharyya 2015; GanOr, Rubin & Bercovici 2015) and chromatography (Biagioni, Cerbelli & Desmet 2022). Despite its importance, the interplay between these three factors has not been studied extensively in the literature, creating a knowledge gap.…”