On-line coupling of immunosorbent and liquid chromatographic analysis for the selective extraction and determination of polycyclic aromatic hydrocarbons in water samples at the ng l −1 level

Abstract

A method employing immunoaffinity chromatography for the selective extraction of polycyclic aromatic hydrocarbons (PAHs) from water was developed. An immunosorbent (IS) based on the immobilization of anti-fluorene antibodies on silica was coupled on-line with LC and applied to the selective extraction of PAHs from water samples. The procedure involves the use of a solubilizer to limit unwanted adsorption on vessels or tubing. Results show that a compromise has to be found between a good solubilization and limitation of the elution from the IS due to the addition of this modifier. The contribution of the selective antigen–antibody interaction to the retention mechanism is demonstrated. The on-line method was optimized for the six more volatile PAHs, and was also applied to the 16 PAHs included in the US Environmental Protection Agency priority list. The sensitivity of the fluorescence detection associated to the selectivity of the extraction sorbent allows one to detect PAHs between 2 and 10 ng l −1 from a sample volume as low as 20 ml. The presence of several PAHs at 20 ng l −1 in surface water was confirmed by spectral identification using diode array detection coupled in series with a fluorescence detector.