Magnetic three-dimensional graphene nanoparticles for the preconcentration of endocrine-disrupting phenols

We have prepared a novel magnetic three-dimensional graphene composite for use as a sorbent for the extraction of the endocrine disrupting phenols (EDPs) including bisphenol A (BPA), 4-tert-butylphenol (t-BP), and 4-tert-octylphenol (t-OP) prior to their determination by HPLC with fluorescence detection. The properties and morphology of the composite were characterized by scanning electron microscopy, and transmission electron microscopy. Several parameters that affect extraction were optimized. The new sorbent displays excellent adsorption capacity for the EDPs. Quantification was achieved by matrix-matched calibration. The calibration plots for the EDPs in a juice sample are linear in the 0.05 to 10 ng mL(-1) concentration range for BPA, and from 0.1 to 10.0 ng mL(-1) for both t-BP and t-OP, with correlation coefficients between 0.9966 and 0.9981. Averaged recoveries range from 88.8 % to 108.8 %. The limits of detection based on a signal to noise ratio of 3 are between 10 and 25 pg mL(-1). The method was successfully applied to the determination of three EDPs in honey peach juice samples.