▎ 摘　　要

A double signal amplification platform for ultrasensitive and simultaneous detection of ascorbic acid (AA), dopamine (DA), uric acid (UA) and acetaminophen (AC) was fabricated by a nanocomposite of ferrocene thiolate stabilized Fe3O4@Au nanoparticles with graphene sheet. The platform was constructed by coating a newly synthesized phenylethynyl ferrocene thiolate (Fc-SAc) modified Fe3O4@Au NPs coupling with graphene sheet/chitosan (GS-chitosan) on a glassy carbon electrode (GCE) surface. The Fe3O4@Au-S-Fc/GS-chitosan modified GCE exhibits a synergistic catalytic and amplification effect toward AA, DA, UA and AC oxidation. The oxidation peak currents of the four compounds on the electrode were linearly dependent on AA, DA, UA and AC concentrations in the ranges of 4-400 mu M, 0.5-50 mu M, 1-300 mu M and 0.3-250 mu M in the individual detection of each component, respectively. By simultaneously changing the concentrations of AA, DA, UA and AC, their electrochemical oxidation peaks appeared at -0.03, 0.15, 0.24 and 0.35 V, and good linear current responses were obtained in the concentration ranges of 6-350, 0.5-50, 1-90 and 0.4-32 mu M with the detection limits of 1, 0.1, 0.2 and 0.05 mu M (S/N=3), respectively. (C) 2013 Elsevier B.V. All rights reserved.