▎ 摘　　要

A nanocomposite of graphene (Gr) and CoFe2O4 nanoparticles was synthesized with a facile preparation method in order to fabricate a modified carbon paste electrode. The morphology and structureof Gr/CoFe2O4 nanocomposite were investigated by scanning electron microscopy (SEM), and X-raydiffraction (XRD). Also, electrochemical characterization of the nanocomposite was demonstrated withelectrochemical impedance spectroscopy. Based on the synergistic effect of Gr and CoFe2O4 nanoparticles, an ultrasensitive electrochemical sensor for acetaminophen (Ac) and codeine (Cod) was successfully fabricated. The linearity ranged from 0.03 to 12.0 mu M for both Ac and Cod. Low detection limits of 0.025 mu Mfor Ac and 0.011 mu M for Cod were achieved based on three times of the standard deviation of the blankover sensitivity (3 s/m). The proposed method was free from interference effects of glucose, ascorbic acid, caffeine, naproxen, alanine, phenylalanine, glycine, and others. No electrode surface fouling was observedduring successive scans. High stability, high sensitivity, and low detection limit made the proposed electrode applicable for the analysis of various real samples. Moreover, its practical applicability was reliableand desirable in biological fluids and pharmaceutical samples analysis. (C) 2014 Elsevier B. V. All rights reserved.