Application of a poly siloxane-based extraction method combined with large volume injection-gas chromatography-mass spectrometry of organic compounds in water samples

This work describes a novel, simple, and inexpensive approach for an absorptive extraction of organic contaminants from aqueous samples applying poly siloxane tubes. After the extraction, the tubes were desorbed with 200 mu L of an organic solvent and 50 mu L of the extract were transferred via large volume injection (LVI) into a gas chromatography-mass spectrometry system (GC-MS). Fourteen organic compounds covering a broad range in polarity with log K-o/w-values between 2.6 (atrazine) and 7 (polychlorinated biphenyl 138, PCB 138) were chosen as model compounds. The experimental parameters affecting the efficiency of the process such as desorption solvents, the addition of salt and pH-change, the extraction and desorption time were carefully optimised. The recoveries were compared with theoretical values. The limits of detection (LODs) were in the ran-e of 0.5-5 ng/L and the precision was 7-15%. The method was successfully applied to the analysis of a contaminated river water sample. (C) 2007 Elsevier B.V. All rights reserved.