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Three-dimensional nanoporous PtSi (NP-PtSi) alloy was prepared by dealloying ternary PtSiAl alloy ribbons. By combining the nanoporous morphology of PtSi and graphene (GR), a new composite material was developed, which was used to modify the surface of a glassy carbon electrode (GCE). The resulting modified electrodes showed an excellent electrocatalytic activity towards the electro oxidation of bisphenol A. Based on differential pulse voltammetry measurements, NP-PtSi/GR/GCE showed linear response over the concentration range 0.30 to 85 μM bisphenol A, while the detection limit was found to be 0.11 μM (S/N = 3). NP-PtSi/GR/GCE showed also satisfactory stability and selectivity over various compounds present in real samples, and they were successfully applied to the determination of bisphenol A in inoculated milk samples. [ABSTRACT FROM AUTHOR]

Three-dimensional nanoporous copper (NPC) was fabricated by dealloying ribbons of an Al-Cu alloy. NPC possesses a clean metal surface and high electrical conductivity. Subsequently, a non-enzymatic electrochemical sensor was obtained by modifying a glassy carbon electrode with nanocomposites containing nanoporous copper and carbon black (NPC-CB) in a nafion matrix. The sensor, if operated at a working voltage of 0.6 V (vs. SCE) in 50 mM NaOH solution, has a linear analytical range that extends from 6.0 μM to 3.4 mM of glucose, and a 2.6 μM detection limit (at an S/N ratio of 3). It also shows good selectivity over ascorbic acid, uric acid, dopamine and carbohydrates (fructose, saccharose, and maltose). The sensor also has a rapid amperometric response to hydrogen peroxide which can be quantified with a 1.2 μM detection limit. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A nanocomposite consisting of helical carbon nanotubes, polyallylamine hydrochloride and CdSe quantum dots was synthesized and used for the electrochemiluminescent determination of dopamine in presence of peroxodisulfate. The nanocomposite was characterized by transmission electron microscopy, UV-absorption and photoluminescence spectroscopy. The electrochemical process was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Under optimized conditions, the ECL intensity decreases linearly with the concentration of dopamine in the 1.0 × 10 mol · L to 2.0 × 10 mol · L range, with a 0.2 × 10 mol · L detection limit. The method represents a rapid, simple and sensitive protocol for the determination of dopamine. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]