An alternative supercritical fluid extraction system for aqueous matrices and its application in pesticides residue analysis

Supercritical fluid extraction (SFE) is a rapid and convenient method for t he isolation of organic compounds from environmental samples. This paper de scribes a supercritical carbon dioxide (CO,) extraction system that uses a newly designed extraction cell to recover organic compounds from an aqueous matrix. Analysis of the extracts by gas chromatography-electron capture de tector (GC-ECD) indicated that the herbicide trifluralin (2,6-dinitro-N,N-d ipropyl-4-trifluoromethylaniline) could be quantitatively extracted by usin g the SFE system proposed with small amounts of sample. The percentage of r ecovery obtained with the SFE system described was twice as high as the res ult obtained using a conventional solid-phase extraction technique. Extract ion by SFE was completed in a short period of time using a simple and low-c ost home-made system that did not require the use of organic solvents.