3. New developments in solid phase extraction

Compared with conventional SPE, SPME represents an interesting advance, as it simplifies implementation, avoids the use of solvents, provides a reusable tool and offers great flexibility of use (application of the same device to liquid and gaseous samples). One drawback, however, is the difficulty of quantifying pollutants due to the adsorption competition often observed when solid materials are used.

One possible solution would be to use "gel" type materials such as PDMS (polydimethylsiloxane), which limit competition and therefore facilitate quantification. What's more, desorption temperatures for these materials are much lower than for porous solids, which would reduce the risk of by-product formation from reactive pollutants.

On the other hand, these polymers generally have much higher detection limits than some porous solids. Consequently,...