not necessary to make any serious modifications in their construction.
Research indicates that the best results can be obtained by carrying out
two-stage adsorption on two different kinds of fibres. The first stage should be
carried out at about 70°C using Carboxen® fibre, and if the result indicates
presence of analytes with high boiling points, a second adsorption should be
carried out at higher temperature (about 100°C), on PDMS fibre [3, 33].