Comparison between different extraction (LLE and SPE) and determination (HPLC and capillary-LC) techniques in the analysis of selected PAHs in water samples

In this work, the extraction of 9 out of 16 PAHs pollutants according to US Environmental Protection Agency (EPA) procedures, was studied through liquid-liquid extraction (LLE) and solid-phase extraction (SPE). The analysis of PAHs was made by high performance liquid chromatography (HPLC), using both a Supelcosil LC 18 (25 cm x 4.6 mm, 5 mu m) column operating in the conventional HPLC mode and a capillary column (20 cm x 0.25 mm, 5 mu m), packed in house with Spherisorb ODS-2 particles and operating in the capillary liquid chromatography (c-LC) mode. Of the extraction techniques used, LLE revealed itself to be efficient in the extraction of the higher-molecular-weight PAHs, while SPE was adequate for the extraction of all PAHs. HPLC revealed to be more sensitive than c-LC in the detection of PAHs in the sample concentration. However, since in c-LC the dilution of the compounds in the mobile phase is less, the mass sensitivity was significantly higher than that obtained with conventional HPLC (that is important when a limited sample amount is available). In the real water samples analyzed no PAH was found under the analytical conditions used.