Trace enrichment of chlorinated phenols from drinking water on chemically bonded sorbents for high-performance liquid chromatography

Abstract

A method for the determination of seven chlorinated phenols, including those in the US Environmental Protection Agency list of priority pollutants, in drinking water is described. Solid-phase extraction on various alkylsilica bonded phases such as phenyl-, octyl- and octadecylsilica was used for sample preconcentration. The dependences of recovery on the eluent volume, sample pH and sample volume were investigated for all the sorbents in order to find the optimum sorbent. Octadecylsilica was found to be the most efficient sorbent. The sample pH was adjusted to 5.0 and, after concentration, the analytes were eluted with 1.2 cm³ of acetonitrile–0.012 mol dm^–3 phosphoric acid (9 + 1). The extract was submitted to reversed-phase high-performance liquid chromatography with acetonitrile–0.007 mol dm^–3 phosphoric acid (51 + 49) as the eluent and ultraviolet detection at 225 nm. Recoveries after 28 d of storage in a refrigerator at 3 °C were also studied. The results were found to agree with those before storage. A comparison between Bakerbond C₁₈ and Separcol C₁₈ is presented. The results obtained were comparable for both types of octadecylsilica. The recoveries of seven chlorinated phenols were higher than 88%. Extracting a 1 dm³ water sample, a detection limit of 2.6 µg dm^–3 was determined for 2-chlorophenol and detection limits between 0.12 and 0.38 µg dm^–3 were obtained for the other six chlorinated phenols.