Low Toxicity Liquid Phase Microextraction Using Deep Eutectic Solvent-Based Ferrofluid for Enrichment Polycyclic Aromatic Hydrocarbon in Environmental Samples

An environmental friendly ferrofluid incorporating hydrophobic deep eutectic solvents derived from fatty acids, specifically caprylic acid, pelargonic acid, capric acid, and lauric acid have been developed. The fundamental physiochemical properties of the synthesised deep eutectic solvents ferrofluid were determined using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and scanning electron microscopy (SEM). Later, they will be used as alternative adsorbents in ferrofluid liquid-phase microextraction. Five polycyclic aromatic hydrocarbons (PAHs) were determined simultaneously using gas chromatography with a flame ionisation detector. The most important extraction parameters were optimised, and the procedure was validated. The selected experimental variables were then optimised using Box–Behnken design (BBD). The developed method is also assessed by Analytical Eco-Scale and Analytical Greenness for greenness method evaluation. Under the optimal conditions, the presented method demonstrated wide linear ranges of 0.005–5 µg mL−1 for all PAHs. The limit of detections (LODs) and quantifications (LOQs) of PAHs varied from 0.4–1.70 ng mL−1 and 1.33–5.67 ng mL−1, respectively. The extraction recoveries of spiked samples for FF-LPME ranged from 75.78 to 118.65