Two polydimethylsiloxane rod extraction methods for the sensitive determination of phenolic compounds in water samples

Simple, precise, and low-cost methods for the simultaneous determination of phenolic endocrine disrupting compounds such as bisphenol A, trichlorophenol, pentachlorophenol, 4-nonylphenol, and 4-octylphenol in water samples were developed. The Direct, in situ derivatization methods are based on polydimethylsiloxane rod extraction followed by liquid desorption and chromatographic analysis by liquid chromatography and diode array detection. Several parameters affecting the extraction and desorption of the phenolic compounds and their acetylated derivates were studied, as well as the chromatographic and detection conditions. For the direct method, determination coefficients (r²) > 0.990 and LODs in the 0.6-2 μg/L range were obtained for all compounds except bisphenol A (9.5 μg/L). With the derivatization-based method, based on in situ acetylation, lower limits of detection (0.3-0.9 μg/L) were obtained for all the compounds with r² > 0.988 and RSDs in the 2-9% range. The developed methods were applied to the analysis of spiked water samples obtaining recoveries of between 60.2 and 131.7% for the direct method, and of between 76.6 and 108.2% for the derivatization-based method. The results demonstrate the feasibility of using these twomethods for determining bisphenol A, trichlorophenol, pentachlorophenol, 4-nonylphenol, and 4-octylphenol in waterThis study has been financed by the Spanish Ministry of Science and Innovation through projects CTM2011-28765-C02-02 and CGL2010-22168-C03-03, and an FPI grant (Ref. BES-2009-024892) awarded to C. Valls-Canteny