title: Rapid and simple pretreatment of human body fluids using electromembrane extraction across supported liquid membrane for capillary electrophoretic determination of lithium.
abstract: Electromembrane extraction was used for simultaneous sample cleanup and preconcentration of lithium from untreated human body fluids. The sample of a body fluid was diluted 100 times with 0.5 mM Tris solution and lithium was extracted by electromigration through a supported liquid membrane composed of 1-octanol into 100 mM acetic acid acceptor solution. Matrix compounds, such as proteins, red blood cells, and other high-molecular-weight compounds were efficiently retained on the supported liquid membrane. The liquid membrane was anchored in pores of a short segment of a polypropylene hollow fiber, which represented a low cost, single use, disposable extraction unit and was discarded after each use. Acceptor solutions were analyzed using capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C(4) D) and baseline separation of lithium was achieved in a background electrolyte solution consisting of 18 mM L-histidine and 40 mM acetic acid at pH 4.6. Repeatability of the electromembrane extraction-CE-C(4) D method was evaluated for the determination of lithium in standard solutions and real samples and was better than 0.6 and 8.2% for migration times and peak areas, respectively. The concentration limit of detection of 9 nM was achieved. The developed method was applied to the determination of lithium in urine, blood serum, blood plasma, and whole blood at both endogenous and therapeutic concentration levels.
authors.affiliation: Institute of Analytical Chemistry of Academy of Sciences of Czech Republic, Brno, Czech Republic.
authors.forename: Lenka
authors.initials: L
authors.lastname: Strieglerová
authors.forename: Pavel
authors.initials: P
authors.lastname: Kubáň
authors.forename: Petr
authors.initials: P
authors.lastname: Boček
mesh_terms: D005591:Chemical Fractionation / Q000295:instrumentation / Q000379:methods; D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D008094:Lithium / Q000032:analysis* / Q000097:blood / Q000302:isolation & purification / Q000652:urine; D008567:Membranes, Artificial; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D008567:Membranes, Artificial; D008094:Lithium