Graphene oxide/ layered double hydroxides@ sulfonated polyaniline: A sorbent for ultrasonic assisted dispersive solid phase extraction of phthalates in distilled herbal beverages.

Otoukesh, Mahdiyeh; Es'haghi, Zarrin; Feizy, Javad; Nerin, Cristina

In this study, the ultrasonic-assisted dispersive solid phase extraction (UA-d-SPE) method coupled to gas chromatography-mass spectrometry (GC-MS) was applied for the analysis of phthalate esters in drinking water and distilled herbal beverages (Rosa, Mentha, Cichorium). A new nanocomposite based on layered double hydroxide supported on graphene oxide was synthesized and modified by sulfonated polyaniline via a simple one-pot in-situ polymerization method. The structure and morphology of the nanocomposite was confirmed by means of complementary techniques: Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The effects of key parameters including adsorbent mass, type and amount of back extraction solvent, extraction and desorption time, pH of the solution and ionic strength were optimized and good precision and sensitivity were achieved. Under the optimum conditions, the limits of detection were between 0.06-0.3 ng mL-1 in aqueous solutions. The hybrid nanomaterial exhibited good adsorption ability toward phthalates in drinking water and distilled herbal beverages. The relative standard deviations (RSD%) for beverage samples varied from 0.1% to 9.9% (n = 3). The relative recoveries varied from 54.5% to 112.6%.