2. Evolution of SPE: solid phase microextraction (SPME)

The principle of solid phase microextraction (SPME) is based on exposing a small fused silica fiber coated with a suitable solid phase [1] to the sample (liquid or gas). Sampling is carried out in static mode, requiring neither a pump nor a flowmeter. After extraction, the fiber containing the pollutants of interest is retracted into a stainless steel needle. Compounds are generally recovered for analysis by thermal desorption directly into the conventional injector of a gas chromatograph (HPLC injection is possible with a specially modified 6-way valve). SPME's ease of use and great adaptability make it a particularly attractive tool for environmental trace analysis as an alternative to conventional SPE. The following paragraphs present some of the advantages and disadvantages of this technique, based on application examples....