Back Cover: Investigating peak dispersion in free‐flow counterflow gradient focusing due to electroosmotic flow

Concentration gradient focusing and separation in a silica nanofluidic channel with a non-uniform electroosmotic flow.

The simultaneous concentration gradient focusing and separation of proteins in a silica nanofluidic channel of various geometries is investigated experimentally and theoretically. Previous modelling of a similar device [Inglis et al., Angew. Chem. Int. Ed., 2011, 50, 7546] assumed a uniform velocity profile along the length of the nanochannel. Using detailed numerical analysis incorporating cha...

Taylor-Aris dispersion in temperature gradient focusing.

Microfluidic temperature gradient focusing (TGF) uses an axial temperature gradient to induce a gradient in electrophoretic flux within a microchannel. When balanced with an opposing fluid flow, charged analytes simultaneously focus and separate according to their electrophoretic mobilities. We present a theoretical and experimental study of dispersion in TGF. We model the system using generali...

Ballistic dispersion in temperature gradient focusing

Molecular dispersion is caused by both molecular diffusion and non-uniform bulk fluid motion. While the Taylor–Aris dispersion regime is the most familiar regime in microfluidic systems, an oft-overlooked regime is that of purely kinematic (or ballistic) dispersion. In most microfluidic systems, this dispersion regime is transient and quickly gives way to Taylor–Aris dispersion. In electrophore...

Electroosmotic flow and dispersion in open and closed porous media

Solute Dispersion by Electroosmotic Flow in Nonuniform Microfluidic Channels

Introduction Dispersion is a phenomenon that determines the resolution of several types of liquid phase chromatography, and is an important component of overall transport through electrokinetic flow systems. The severe dispersion of solute as it travels through a U-turn, for example, has attracted recent attention for this reason [1]. In “ideal” electroosmotic flow through uniform, straight cha...