Supercritical CO2 desorption for air sampling analysis.

In this study, we propose to develop an analytical device able to desorb any organic compound from any sorbent without using solvents and perform online analysis with gas, liquid and supercritical chromatography. In the first step of this study, we designed a re-usable sampler that can be used either in active or passive mode. We proved the efficiency of scCO2 for BTX extraction on activated charcoal using offline analysis. In this second step, a mass spectrometer was coupled directly to the extractor in order to monitor the desorption kinetics of different sorbent-substance pairs. These desorption kinetic curves give very interesting information for extraction parameter optimisation as a function of the nature of interaction between the substance and the sorbent. Each sorbent-substance pair used in all the Metropol database was studied by spiking the substance in vapour phase on the re-usable sampler filled with the relevant sorbent. The optimal extraction conditions were therefore determined according to the extraction profile.