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SOLVENT EXTRACTION OF ORGANIC WATER POLLUTANTS
Citation:
Webb, R. SOLVENT EXTRACTION OF ORGANIC WATER POLLUTANTS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-78/067 (NTIS PB289237).
Description:
Based on experiments with model systems of known organic water pollutants and environmental samples, conclusions are reached concerning the best general solvent for extraction and the most appropriate methods for related manipulations. Chloroform, methylene chloride-ether mixtures, and methylene chloride are the best solvents for general extraction purposes. Methylene chloride is recommended. Most samples should be extracted first at basic and then acidic pH. The analyst has very little control over emulsion formation through choice of solvent or by pH adjustment, but continuous liquid-liquid extractors overcome most emulsion problems. For highest recovery of extracted pollutants, extracts should not be treated with drying agents before concentration. Final evaporation of extracts using a micro-Snyder column is recommended over evaporation with a steam of inert gas.