title: Electromembrane extraction using stabilized constant d.c. electric current--a simple tool for improvement of extraction performance.
abstract: This contribution presents an experimental approach for improvement of analytical performance of electromembrane extraction (EME), which is based on the use of stabilized constant d.c. electric current. Extractions were performed using a high voltage power supply, which provided stabilized constant d.c. current down to 1μA and facilitated current-controlled transfer of ions of interest from a donor solution through a supported liquid membrane (SLM) into an acceptor solution. Repeatability of the extraction process has significantly improved for EME at constant electric current compared to EME at constant voltage. The improved repeatability of the extraction process was demonstrated on EME-capillary electrophoresis (EME-CE) analyses of selected basic drugs and amino acids in standard solutions and in human urine and serum samples. RSD values of peak areas of the analytes for EME-CE analyses were about two-fold better for EME at constant electric current (2.8-8.9%) compared to EME at constant voltage (3.6-17.8%). Other analytical parameters of the EME-CE methods, such as limits of detection, linear ranges and correlation coefficients were not statistically different for the two EME modes. Moreover, EME at constant electric current did not suffer from SLM instabilities frequently observed for EME at constant voltage.
authors.affiliation: Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic, Veveří 97, CZ-60200 Brno, Czech Republic.
authors.forename: Andrea
authors.initials: A
authors.lastname: Slampová
authors.forename: Pavel
authors.initials: P
authors.lastname: Kubáň
authors.forename: Petr
authors.initials: P
authors.lastname: Boček
mesh_terms: D000596:Amino Acids / Q000097:blood / Q000302:isolation & purification; D005591:Chemical Fractionation / Q000295:instrumentation / Q000379:methods*; D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000379:methods; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D057230:Limit of Detection; D008567:Membranes, Artificial; D004364:Pharmaceutical Preparations / Q000302:isolation & purification / Q000652:urine; D015203:Reproducibility of Results
chemical_list: D000596:Amino Acids; D007477:Ions; D008567:Membranes, Artificial; D004364:Pharmaceutical Preparations