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

Electromembrane extraction (EME) was carried out using a novel instrumentation capable of impedometric monitoring of the system during the extraction. This instrumentation involves a classical two-electrode assembly fed by two time-resolved potential functions, the first for the extraction of analyte and the second for obtaining the impedance information. The impedometric analysis of the system was achieved by Laplace transformation of the current recorded during the extraction.

Surfactant assisted pulsed two-phase electromembrane extraction followed by GC analysis for quantification of basic drugs in biological samples.

In this work, a simple and efficient surfactant assisted pulsed two-phase electromembrane extraction (SA-PEME) procedure combined with gas chromatography (GC) has been developed for the determination of alfentanil, sufentanil and methadone in various samples. It has been found that the addition of anionic surfactant causes the accumulation of the cationic analytes at the SLM/solution interface resulting in an easier transfer of the analytes into the organic phase. The method was accomplished with 1-octanol as the acceptor phase and supported liquid membrane (SLM) by means of an 80 V pulsed electrical driving force and the extraction time of 20 min.

Electromembrane extraction through a virtually rotating supported liquid membrane.

Electromembrane extraction (EME) of model analytes was carried out using a virtually rotating supported liquid membrane (SLM). The virtual (nonmechanical) rotating of the SLM was achieved using a novel electrode assembly including a central electrode immersed inside the lumen of the SLM and five counter electrodes surrounding the SLM. A particular electronic circuit was designed to distribute the potential among five counter electrodes in a rotating pattern.

The effect of electric field geometry on the performance of electromembrane extraction systems: footprints of a third driving force along with migration and diffusion.

The distribution of electric field vectors was first calculated for electromembrane extraction (EME) systems in classical and cylindrical electrode geometries. The results showed that supported liquid membrane (SLM) has a general field amplifying effect due to its lower dielectric constant in comparison with aqueous donor/acceptor solutions. The calculated norms of the electric field vector showed that a DC voltage of 50 V can create huge electric field strengths up to 64 kV m(-1) and 111 kV m(-1) in classical and cylindrical geometries respectively.

Electronic simulation of the supported liquid membrane in electromembrane extraction systems: Improvement of the extraction by precise periodical reversing of the field polarity.

In order to understand the limitations of electromebrane extraction procedure better, a simple equivalent circuit has been proposed for a supported liquid membrane consisting of a resistor and a low leakage capacitor in series. To verify the equivalent circuit, it was subjected to a simulated periodical polarity changing potential and the resulting time variation of the current was compared with that of a real electromembrane extraction system. The results showed a good agreement between the simulated current patterns and those of the real ones.

Application of a magnetic molecularly imprinted polymer for the selective extraction and trace detection of lamotrigine in urine and plasma samples.

Magnetic molecularly imprinted polymers have been synthesized for the selective preconcentration and trace determination of lamotrigine (LTG) in urine and plasma samples. The magnetic nanoparticles were modified by tetraethyl orthosilicate and 3-methacryloxypropyl trimethoxysilane before imprinting. The magnetic molecularly imprinted polymers were prepared via surface molecular imprinting technique, using Fe3 O4 as a magnetic component, LTG as template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, and 2,2'-azobisisobutyronitrile as a radical initiator in methanol/acetonitrile (50:50, v/v) as the porogen.

A selective electromembrane extraction of uranium (VI) prior to its fluorometric determination in water.

A novel method for the selective electromembrane extraction (EME) of U(6+) prior to fluorometric determination has been proposed. The effect of extraction conditions including supported liquid membrane (SLM) composition, extraction time and extraction voltage were investigated. An SLM composition of 1% di-2-ethyl hexyl phosphonic acid in nitrophenyl octyl ether (NPOE) showed good selectivity, recovery and enrichment factor.