ABSTRACT
The use of membranes for extraction in analytical chemistry has been increasing during recent years. The main intention is to selectively extract and enrich compounds to be determined (analytes) from chemically more or less complex samples. In contrast to many technical uses of membranes, in analytical applications, it is imperative to recover as efciently as possible the extracted analytes so they can be transferred to suitable analytical instruments for the nal determination in a quantitative way. Another difference from technical uses is that the volume scale is small; extracts are seldom larger than a milliliter, often only several microliters.
