Analysis of Polycyclic Aromatic Hydrocarbons in Water Samples Using Deep Eutectic Solvent as a Dispersant in Dispersive Liquid–Liquid Microextraction Based on the Solidification of Floating Organic Droplet

Abstract

A novel dispersive liquid–liquid microextraction method based on the solidification of a floating organic droplet was proposed to pre-concentrate 16 polycyclic aromatic hydrocarbons (PAHs) from water samples prior to their determination using gas chromatography–mass spectrometry, in which the effect of hydrophilic deep eutectic solvent (DES) used as a dispersant was investigated. The main extraction parameters were optimized, and the procedure was validated. DES2 synthesized using choline chloride with acetic acid at a molar ratio of 1:2 was selected as the dispersant. Under the optimum extraction conditions, 12 mL of the water sample was injected into the mixed solvent containing 60 μL of 1-dodecanol (extractant) and 316 μL of DES2, ultrasound-mixed for 4 min, and then centrifuged for 5 min to separate the phases. The proposed method showed good linearity in the range of 0.02–5.0 μg/L; the limits of detection were 3.5–14.1 ng/L, the limits of quantification were 11.8–46.9 ng/L, the relative standard deviations were below 6.1%, and the enrichment factors ranged from 142 to 175 for the 16 PAHs. Finally, the proposed method was successfully employed to determine PAHs in real water samples.