Optimization of SFE for the determination of chlorinated hydrocarbons at the part-per-trillion level

The applicability of SFE for trace analysis was expanded by an intensive cleaning procedure of the SFE equipment and development of an adsorbing device for commercial carbon dioxide. For a selection of chlorinated hydrocarbons, the limit of detection was reduced to less than or equal to 20 pg/g of solid matrix. The procedure can be transferred to other analytical SF delivery systems for off- and on-line SFE, and also to an SFC apparatus. Also, the blank value for the analysis of nonchlorinated aliphatic and aromatic compounds was improved significantly. The purity of carbon dioxide is no longer the limiting factor for trace analysis with SFE.