Simultaneous extraction and preconcentration of aniline, phenol, and naphthalene using magnetite–graphene oxide composites before gas chromatography determination

Abstract

The coextraction of acidic and basic compounds from different mediums is a significant concept in sample preparation. In this work, simultaneous extraction of acidic, basic, and neutral analytes in a single step was carried out for the first time. This procedure employed the dispersive solid-phase microextraction of analytes with magnetic graphene oxide (graphene oxide/Fe3 O4 ) sorbent followed by gas chromatography with flame ionization detection. After the adsorption of analytes by vortexing and decantation of the supernatant with a magnet, the sorbent was eluted with acetonitrile/methanol (2:1) mixture. The parameters affecting the extraction efficiency were optimized and obtained as follows: sorbent amount 60 mg, desorption time 1 min, extraction time 5 min, pH of the sample 7, sample volume 20 mL, and elution solvent volume 0.3 mL. Under the optimum conditions, linear dynamic ranges were achieved in the range of 0.5-4, 0.25-4, and 0.25-2 μg/mL and limits of detection were 0.341, 0.110, and 0.167 μg/mL for aniline, phenol, and naphthalene, respectively. The relative standard deviations were in the range of 3.3-5.7% in eight repeated extractions. Finally, the applicability of the method was evaluated by the extraction and determination of analytes in stream water and drinking water samples and satisfactory results were obtained.