Determination of polycyclic aromatic hydrocarbons using lab on valve dispersive liquid-liquid microextraction coupled to high performance chromatography.

In this work, dispersive liquid-liquid microextraction (DLLME) method was applied for high performance liquid chromatography (HPLC) determination of 15 PAHs in aqueous matrices.The extraction procedure was automated using a system of multisyringe flow injection analysis coupled to HPLC instrument with fluorescence detector. Factors affecting the extraction process, such as type and volume of extraction and dispersive solvent, extraction time and centrifugation step were investigated thoroughly and optimized utilizing factorial design. The best recovery was achieved using 100 µL of trichloroethylene as the extraction solvent and 900 µL of acetonitrile as the dispersive solvent.The results showed that extraction time has no effect on the recovery of PAHs. The enrichment factors of PAHs were in the range of 86-95 with limits of detection of 0.02-0.6 µg L(-1). The linearity was 0.2-600 µg L(-1) for different PAHs. The relative standard deviation (RSD) for intra- and inter-day of extraction of PAHs were in the range of 1.6-4.7 and 2.1-5.3, respectively, for five measurements.The developed method was used to assess the occurrence of 15 PAHs in tap water, rain waters and river surface waters samples.