Related Experiment Video
Updated: May 25, 2026

Merging Ion Concentration Polarization between Juxtaposed Ion Exchange Membranes to Block the Propagation of the Polarization Zone
Published on: February 23, 2017
Permeation of a fully ionized species across a polarized supported liquid membrane
Matěj Velický1, Kin Y Tam, Robert A W Dryfe
1School of Chemistry, University of Manchester Oxford Road, Manchester M13 9PL, UK.
Abstract:
An analytical technique for the detection of permeation of a fully ionized analyte across a lipophilic membrane is reported. The system, which is comprised of two aqueous compartments (donor and acceptor) separated by a supported liquid membrane, is based on the parallel artificial membrane permeation assay (PAMPA), widely used in the drug discovery process to estimate permeability in vivo. The in situ spectroelectrochemical method developed here employs mechanical stirring of the solution phases on either side of the membrane, external polarization of the membrane, and in situ detection of the analyte via UV-vis spectrophotometry. The flux of the crystal violet cation across the membrane is simultaneously measured via UV-vis spectrophotometry and voltammetry/chronoamperometry as a function of applied potential. The relative contribution of two permeation modes, i.e., that due to naked ions and ion-pairs, is thereby quantified. The open circuit potential difference between the two aqueous compartments and the cyclic voltammetric response are also recorded as a function of time and compared with the predicted values.
Related Concept Videos
Diffusion
Diffusion
Pore Transport and Ion-Pair Transport
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct microscopic...
Drug Absorption Mechanism: Passive Membrane Transport
The Significance of Membrane Transport
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
Passive Diffusion: Overview and Kinetics
When administered orally, drugs establish a substantial concentration gradient between the gastrointestinal (GI) lumen and the bloodstream, expediting their diffusion into...

