Extraction strategies of PAHs from grilled meat for their determination by HPLC–DAD

Strategies have been used in this work for rapid and precise extraction of polycyclic aromatic hydrocarbons (PAHs) from grilled meat. Samples were pre-extracted with acetonitrile/potassium hydroxide under microwave irradiation, and after dilution with water subjected to two alternative pre-concentration and clean-up methods. In the first method, the extract was treated with hydrophilic deep eutectic solvent (DES) of choline chloride:phenol (1:2, molar ratio), and the extract phase separated by salt-assisted liquid–liquid extraction (SALLE) with acetonitrile. This method was found better than the conventionally used emulsification with tetrahydrofuran. In the other method, a methanolic solution of 1,4-dichlorobenzene (DCB) was injected into the extract when a cloudy solution was obtained due to dispersion of DCB particles. The sorbent with extracted PAHs was collected on bare Fe3O4 nanoparticles; a modification which was faster than the usually opted centrifugation in dispersive solid phase extraction. Matrix polar compounds and proteins were excluded due to low polarity of DES-SALLE combination and non-polar surface of DCB. Linear calibration graphs are obtained in HPLC–DAD in the range 0.1–1000 µg kg−1 of PAHs in both extraction methods (using 10 mL of standard extract). The limits of detection (S/N = 3) of PAHs (determined on tenfold diluted standard extract) were in the range 11–25 ng kg−1 by the DES method and 14–30 ng kg−1 by the DCB method, which were better than obtained by many of currently used extraction methods. The enrichment factors ranged 75–115 in DES extraction method, 60–95 in DCB method. The methods have been applied to the real samples of grilled meat, and the results found by the present methods agreed together and with those found by the standard methods. DES method in combination with SALLE was found more convenient to operate.