Membrane extraction techniques in bioanalysis

Membrane-based extraction techniques offer efficient alternatives to classi cal sample preparation techniques, especially liquidliquid extraction (LLE) . They permit high selectivity high enrichment factors as well as good poss ibilities for automation. it is possible to tune the selectivity by chemica l means and selective enrichment for specified classes of chemical compound s can be obtained. At the same time the disadvantages of LIE are avoided, s uch as consumption of organic solvents and the need for manual handling. Some examples from the field of biomedical analysis are discussed. They sho w the high selectivity and high enrichment factors that can be obtained. Al so, the possibilities for automated interfacing to chromatographic instrume nts for quantitative analysis are demonstrated.