title: Membrane-based sample preparation for ion chromatography-Techniques, instrumental configurations and applications.
abstract: Sample preparation is the bottleneck of many analytical methods, including ion chromatography (IC). Procedures based on the application of membranes are important, yet not well appreciated means for clean-up and analyte preconcentration of liquid samples. Filtration, ultrafiltration, the variety of dialysis techniques, i.e. passive dialysis, Donnan dialysis and electrodialysis, as well as gas-diffusion are being reviewed here with respect to their application in combination with IC. Instrumental aspects including hardware requirements, configuration of membrane separation units and membrane characteristics are presented. Operation in batch and flow-through mode is described with emphasis on the latter to in-line coupling with IC, permitting fully automated operation. Attention is also drawn to dialysis probes and microdialysis both providing options for in-situ measurements with inherent selective sampling of analytes and sample preparation. The respective features of the various techniques are outlined with respect to the possibilities of matrix removal and selectivity enhancement. In this article, we provide examples of application of the diverse membrane separation techniques and discuss the benefits and limitations thereof.
authors.affiliation: Institut für Technischen Umweltschutz, Technische Universität Berlin, Str. d. 17. Juni 135, D-10623 Berlin, Germany. Electronic address: wolfgang.frenzel@tu-berlin.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Frenzel
authors.affiliation: Institut für Technischen Umweltschutz, Technische Universität Berlin, Str. d. 17. Juni 135, D-10623 Berlin, Germany. Electronic address: i.markeviciute@tu-berlin.de.
authors.forename: Inga
authors.initials: I
authors.lastname: Markeviciute
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000295:instrumentation* / Q000379:methods*; D002853:Chromatography, Liquid / Q000295:instrumentation*; D004058:Diffusion; D008567:Membranes, Artificial; D014462:Ultrafiltration
chemical_list: D008567:Membranes, Artificial
keywords: Dialysis; Gas diffusion; In-line coupling to ion chromatography; Membrane separation; Microdialysis; Sample preparation