Electromembrane extraction: Distribution or electrophoresis?

Abstract

This paper presents for the first time a phenomenological theoretical model for the time dependent distribution of analytes during electromembrane extraction (EME). The model was verified experimentally for a range of model drugs and peptides. Analytes were extracted from an acidified aqueous sample solution, through an organic supported liquid membrane (SLM), and into an acidified aqueous acceptor solution. Mass transfer was governed by an applied electric field across the SLM. A rapid depletion was seen in the sample during extractions, with a steady increase in the amount accumulated in the acceptor solution. This was in good accordance with the theoretical model. A deviation from the modeled behavior was seen for some of the peptides where trapping of analyte in the SLM was high. The results demonstrated for the first time that EME behaved like a distribution system, with voltage dependent distribution coefficients. In addition, electrokinetic migration was observed across the SLM, which added an electrophoretic component to the mass transfer. This improved theoretical understanding will be highly beneficial for future optimization and development of applications using EME.

Mass transfer in electromembrane extraction—The link between theory and experiments

“…Several studies have described and discussed theoretical models for mass transfer in EME . The proposed models are based on assumptions to simplify the final mass transfer equations.…”

Impedometric monitoring of the behavior of the supported liquid membrane in electromembrane extraction systems: An insight into the origin of optimized experimental parameters

“…Solution resistance, R sol As described in previous works [11,23], the applied potential in EME is distributed between donor/acceptor solutions and SLM. According to Ohm's law, the portion of the applied potential that drops in the donor solution is proportional to the solution resistance:…”

Selective electromembrane extraction based on isoelectric point: Fundamental studies with angiotensin II antipeptide as model analyte

“…All these stock solutions were stored at À 32 1C and protected from light [26,28]. The sample for the extraction process (step 1) was obtained daily by diluting the stock solutions with 25 mM phosphate buffer with a pH of 3.50.…”

“…Up to date, a few research articles have reported EME of peptides with the hollow fiber EME format [17,18,[22][23][24][25][26]. However, high system-current and low recoveries for the peptides have been the main challenges [6,19].…”