Electro membrane extraction, or EME, is a miniaturized liquid-liquid extraction technique developed for sample preparation of aqueous samples prior to analysis by

chromatography In chemical analysis, chromatography is a laboratory technique for the Separation process, separation of a mixture into its components. The mixture is dissolved in a fluid solvent (gas or liquid) called the ''mobile phase'', which carries it ...

electrophoresis Electrophoresis is the motion of charged dispersed particles or dissolved charged molecules relative to a fluid under the influence of a spatially uniform electric field. As a rule, these are zwitterions with a positive or negative net ch ...

mass spectrometry Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a ''mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used ...

, and related techniques in

analytical chemistry Analytical skill, Analytical chemistry studies and uses instruments and methods to Separation process, separate, identify, and Quantification (science), quantify matter. In practice, separation, identification or quantification may constitute t ...

. EME involves the use of a small supported liquid membrane (SLM) sustained in the wall of a porous hollow fiber, and application of an electrical field across the SLM.

Principle

Target compounds are extracted from an aqueous sample, through a μL-volume of organic solvent sustained as a thin supported liquid membrane (SLM) in the pores in the wall of a porous hollow fiber, and into an acceptor solution inside the lumen of the hollow fiber. Extraction is based on electrokinetic migration in an electrical field sustained across the SLM. The volume of the acceptor solution is typically 5-25 μL. The acceptor solution is an aqueous solution, and can be analyzed by liquid chromatography (LC) or capillary electrophoresis (CE).

Advantages

EME is closely related to liquid-phase microextraction (LPME) and provides high pre-concentration and efficient sample clean-up. In addition, because the extraction is performed under the influence of an electrical field, the extraction selectivity can be controlled by the direction and the magnitude of the electrical field.Astrid Gjelstad, Stig Pedersen-Bjergaard Electromembrane extraction – Three phase electrophoresis for future preparative applications Electrophoresis 35 (2014) 2421-2428.

References

{{reflist * * * * Extraction (chemistry) Laboratory techniques

Principle

Advantages

Further reading

References