Optimization of two different dispersive liquid–liquid microextraction methods followed by gas chromatography–mass spectrometry determination for polycyclic aromatic hydrocarbons (PAHs) analysis in water

Novel sample preparation methods termed “up-and-down shaker-assisted dispersive liquid−liquid microextraction (UDSA−DLLME)” and “water with low concentration of surfactant in dispersed solvent-assisted emulsion dispersive liquid–liquid microextraction (WLSEME)” coupled with gas chromatography–mass spectrometry (GC–MS) have been developed for the analysis of 11 polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. For UDSA–DLLME, an up-and-down shaker-assisted emulsification was employed. Extraction was complete in 3 min. Only 14 μL of 1-heptanol was required, without a dispersive solvent. Under the optimum conditions, the linear range was 0.08−100 µg L−1, and the LODs were in the range 0.022−0.060 µg L−1. The enrichment factors (EFs) ranged from 392 to 766. Relative recoveries were between 84% and 113% for river, lake, and field water. In WLSEME, 9 μL of 1-nonanol as extraction solvent and 240 μL of 1 mg L−1 Triton X-100 as surfactant were mixed in a microsyringe to form a cloudy emulsified solution, which was then injected into the samples. Compared with other surfactant-assisted emulsion methods, WLSEME uses much less surfactant. The linear range was 0.08−100 µg L−1, and the LODs were 0.022−0.13 µg L−1. The EFs ranged from 388 to 649. The relative recoveries were 86−114% for all three water specimens.