Solid-Phase Extraction and LC with Fluorescence Detection for Analysis of PAHs in Rainwater

Abstract

The efficiency of extraction of polycyclic aromatic hydrocarbons (PAHs) from rainwater by solid-phase extraction (SPE) with three different types of cartridge, and analysis by high-performance liquid chromatography with fluorescence detection, are discussed in this paper. Three cartridges were investigated but only one was suitable. After equilibration in a desiccator for 65–80 h or in ambient air for 90–100 h the SPE cartridges were activated with 5 mL dichloromethane then 5 mL 2-propanol. The volume of sample passed through the cartridges was 50 mL; after loading of the sample the cartridges were dried under vacuum for approximately 20 min by application of a pressure of 15 mbar to the SPE manifold. The PAHs were eluted with 5 mL dichloromethane–hexane, 50:50 (v/v). The flow rate used for conditioning, sample loading, and elution was 2.5 mL min⁻¹, achieved by application of a pressure of 6 mbar. For analysis of PAHs in rainwater, recovery was between 67 and 99%, the relative standard deviation varied between 2 and 5%, and the detection limits of the method were less than 16.9 ng L⁻¹ for several PAHs. These optimum conditions were used for analysis of rainwater collected between June 2002 and May 2003 at two sites in Alsace (eastern France) and 17 PAHs were quantitatively determined. Concentrations varied between 1.6 and 968.1 ng L⁻¹.