Facile simultaneous electrochemical determination of codeine and acetaminophen in pharmaceutical samples and biological fluids by graphene-CoFe_2O_4 nancomposite modified carbon paste electrode

摘要

A nanocomposite of graphene (Gr) and CoFe_2O_4 nanoparticles was synthesized with a facile preparation method in order to fabricate a modified carbon paste electrode. The morphology and structure of Gr/CoFe_2O_4 nanocomposite were investigated by scanning electron microscopy (SEM), and X-ray diffraction (XRD). Also, electrochemical characterization of the nanocomposite was demonstrated with electrochemical impedance spectroscopy. Based on the synergistic effect of Gr and CoFe_2O_4 nanoparticles, an ultrasensitive electrochemical sensor for acetaminophen (Ac) and codeine (Cod) was successfully fabricated. The linearity ranged from 0.03 to 12.0 μM for both Ac and Cod. Low detection limits of 0.025 μM for Ac and 0.011 μM for Cod were achieved based on three times of the standard deviation of the blank over 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 observed during 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 reliable and desirable in biological fluids and pharmaceutical samples analysis.