Gas/Liquid and Liquid/Liquid Solvent Extraction in Flow Analysis with the Chromatomembrane Cell

Since twelve years the Chromatomembrane Cell has been proposed as a new and versatile device for extraxtion procedures in the flow based analysis. In the meantime a remarkable number of papers was submitted dealing with applications of the novel method to all the conceivable varieties of flow injection and sequential injection analysis. The device supports important analytical procedures such as sampling, sample preparation, and preconcentration each being combined with a phase transfer of the analyte. The Chromatomembrane Cell can be coupled to most of the modern detectors which work computer aided in the laboratories of today. Centrepiece of the cell is a block made from biporous hydrophobic PTFE, inside which polar (in the macropores) and nonpolar (in the micropores) solvents come into a close contact with each other and might flow independently with different flow rates. Microporous PTFE membranes prevent polar phases from their flowthrough into directions which are reserved for nonpolar fluids only. Thus, a strict control over the fluxes can be established at the analysts request. Especially, that PTFE block offers outstanding possibilities as a sampling unit for air monitoring.