Amino-functionalized Fe3O4–graphene oxide nanocomposite as magnetic solid-phase extraction adsorbent combined with flame atomic absorption spectrometry for copper analysis in food samples

A new amino-functionalized Fe3O4–graphene oxide nanocomposite (AF-Fe3O4–GO) was synthesized. The properties were characterized by Fourier-transform infrared spectrometry and scanning electron microscopy. The obtained adsorption results showed that the AF-Fe3O4–GO had great adsorptive ability toward Cu(II). Based on these, an effective magnetic solid-phase extraction (MSPE) procedure coupled with flame atomic absorption spectrometry for the pre-concentration and determination of Cu(II) in food samples was developed. Various experimental parameters that could affect the extraction efficiency were investigated in detail. Under optimum conditions, enhancement factor of the method for Cu(II) was found to be 95.08. The proposed method was successfully applied for the analysis of food samples with recoveries ranging from 97.2 to 99.1 % and a correlation coefficient (R2) of 0.999. Good linearity was obtained, ranging from 1 to 100 µg L−1. The limit of detection and precision of the method were 0.9 ng mL−1 and 1.23 %, respectively. It was confirmed that AF-Fe3O4–GO nanocomposite can be a highly effective MSPE adsorbent used for trace Cu(II) analyses.