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In this work, a sensor for quantitative detection of uric acid (UA) is successfully prepared by electrodepositing Nickel–Copper (Ni–Cu) alloy nanoparticles on poly (3,4-ethyldioxythiophene) modified nitrogen-containing grapheme (Ni–Cu/PEDOT/NGE). The anchoring of PEDOT and Cu–Ni alloy nanoparticles on NGE not only prevents the agglomeration of NGE, but also improves the catalytic activity of the composites. Ni–Cu/PEDOT/NGE shows high electrochemical performance to UA and the oxidation of UA on its interface was an action with two protons and two electrons. Under the optimized condition, the response current of the sensor is linear with UA concentration within the range of 0.1–10 μ M and 10–50 μ M. A low detection limit of 0.059 μ M at S/ N = 3 is obtained. Additionally, the fabricated electrochemical sensor with good sensitivity and selectivity to UA may be promising for practical clinical testing. Poly(3,4-ethylenedioxythiophene) and nickel–copper alloy nanoparticles are modified on nitrogen-doped graphene via electropolymerization and electrodeposition (Ni–Cu/PEDOT/NGE). The oxidation of uric acid on the interface of Ni–Cu/PEDOT/NGE is an action with two protons and two electrons. [ABSTRACT FROM AUTHOR]

A simple and sensitive label-free electrochemical biosensor for nimodipine was fabricated by using nitrogen-doped graphene (NGE) modified electrode. The surface morphology and electron transfer behavior of the modified electrodes were studied by scanning electron microscopy and electrochemical impedance spectroscopy, respectively. The electrochemical behaviors of nimodipine at the modified electrodes were investigated by using cyclic voltammetry. On the basis of the excellent electrocatalytic activity of NGE, an obvious cathodic peak of nimodipine could be caused at the NGE modified glassy carbon electrode (GCE), moreover, the electrochemical signal was greatly enhanced compared with the undoped graphene modified GCE. Under the optimized conditions, the present sensor showed excellent performances for nimodipine detection including wide linear range of 0.02–3 μM, low detection limit (9.1 nM), good selectivity to the general coexisted interferences, etc. The proposed biosensor was also successfully applied to validate its capability for the analysis of nimodipine in tablets. The work would promote the potential application of NGE as an excellent material in fabricating electrochemical sensors for chemical or biochemical analysis. [ABSTRACT FROM AUTHOR]