Determination of eleven priority EPA phenolics at ng L-1 levels by on-line solid-phase extraction and liquid chromatography with UV and electrochemical detection

The eleven priority, EPA phenolic pollutants were determined by liquid chromatography followed by two detectors in series; UV and electrochemical. Three different adsorbents, Envi-Carb (a carbon black) and two functionalized polymeric resins, Bond Elut PPL and another synthesized in our laboratory with an o-carboxybenzoyl moiety, were compared for solid-phase extraction (SPE) to detect lower concentrations of the eleven phenolics in natural waters. Higher recoveries were obtained using the functionalized polymeric adsorbents compared with Envi-Carb. When real samples were analysed, the synthetic adsorbent gave lower interference than Bond Elut PPL and phenol was determined at low levels with no humic and fulvic acid interference when Na2SO3 was added. The linearity range for most compounds in tap water nias 0.05-20 mu g L-1 and the limits of detection were < 35 ng L-1. Repeatability and reproducibility between days for real samples spiked at 0.1 mu g L-1, expressed as relative standard deviation, were < 8 % and 10 %, respectively.