Adsorption mechanism of polycyclic aromatic hydrocarbons on polythiophene-graphene covalent complex and its analytical application in food contact materials

A covalent complex of 3,4-ethylenedioxythiophene (EDOT) and graphene oxide (GO) was electrodeposited on an etched stainless-steel wire to obtain a robust polymeric film. The film presents a more fluffy porous morphology and higher thermal stability, which can be acted as solid phase microextraction (SPME) coating. The adsorption isotherms of the polycyclic aromatic hydrocarbons (PAHs) on the covalent PEDOT-GO coating showed the π stacking interaction happened between them. The coating showed high extraction efficiency for four PAHs, including naphthalene, 1-methyl naphthalene, acenaphthene and fluorene, which was nearly three times that of the PEDOT coating and higher than the commercial coatings. The covalent PEDOT-GO coating was applied to headspace SPME coupled with gas chromatography for the determination of PAHs. The linear range was 0.015–15 μg/L ( R 2 >0.99) and the limit of detection was 0.005–0.01 μg/L (S/N=3). It was successfully applied for the migration determination of PAHs in three types of food contact materials and the recovery was satisfactory in the range of 70–103%.