Comparison of solvent extractions and resin adsorption for isolation of mutagenic compounds from chlorinated drinking water with high humus content

Abstract

Several methods of liquid-liquid extraction, and XAD resin and Blue-Cotton adsorption were compared for concentrating mutagenic organic compounds from humus-containing drinking water. Mutagenicity was measured by the Ames' test, using strains TA 100 and TA 98 without metabolic activation. Continuous liquid-liquid extraction for 48 h and resin adsorption gave comparable and adequately reproducible results. “Salting out” by sodium chloride improved the yield to some extent. Diethyl ether was more effective as extractant than dichloromethane. Two consecutive extractions in Ultra Turrax with salting out were needed to yield the same level of activity as continuous liquid-liquid extraction. Extraction by mechanical mixing as well as adsorption by Blue-Cotton gave inadequate yields. The highest yield for mutagenic compounds was obtained from acid (pH 1 or 2) solution by extraction as well as by resin adsorption. It is concluded that the main mutagens in humus-rich chlorinated drinking water are acidic polar compounds.