Graphene Flakes Decorated with Dispersed Gold Nanoparticles as Nanomaterial Layer for ISEs.

This paper proposes a new type of solid-contact layer based on graphene/gold nanoparticles for ion-selective electrodes. A novel approach to preparing the material for intermediate layer by modifying the graphene flakes by gold nanoparticles is presented. With this approach, we observed a large surface area of material and in consequence high electrical capacitance of electrodes. We have obtained satisfactory results demonstrating that the modification of graphene with gold allows for enhancing electrical and wetting properties of carbon nanomaterial. Electrical capacitance of designed nanocomposite-contacted electrode equals to approximately 280 µF, which in consequence ensures great long-term potential stability defined by the potential drift of 36 µV/h. The modification of graphene with nanoparticles completely changed its wetting properties, as the designed material turned out to be hydrophobic with a water contact angle of 115°. Graphene/gold nanoparticles-contacted electrodes are insensitive to the changing light conditions, exhibiting near-Nernstian response in the potassium concentration range between 10-5.9 M and 10-1 M of K+ ions and may be applied in the pH range between 2 and 10.5.

Nanoscopic insights into the surface conformation of neurotoxic amyloid ß oligomers.

Raman spectroscopy assisted by localized plasmon resonances generating effective hot spots at the gaps between intertwined silver nanowires is herein adopted to unravel characteristic molecular motifs on the surface of Aß42 misfolded oligomers that are critical in driving intermolecular interactions in neurodegeneration.

Potentiometric sensors with carbon black supporting platinum nanoparticles.

For the first time, a single-piece, all-solid-state ion-selective electrode was fabricated with carbon black supporting platinum nanoparticles (PtNPs-CB) and a polymeric membrane. The PtNPs-CB, as an intermediate layer, was drop-casted directly on the solid substrate, and then an ionophore-doped solvent polymeric membrane was added in order to form a sensor. The performance of the newly developed electrodes was evaluated on the basis of potassium and nitrate ions. The stability of the electrical potential for the electrodes was examined by performing current-reversal chronopotentiometry, and the influence of the interfacial water film was assessed by the potentiometric aqueous-layer test. Fabricated potassium- and nitrate-selective electrodes displayed a Nernstian slope and several outstanding properties such as high long-term potential stability, potential repeatability, and reproducibility.

Platinum nanoparticles intermediate layer in solid-state selective electrodes.

A platinum nanoparticles (PtNPs) layer is used for the first time as an ion-to-electron transducer in a solid-state ion-selective electrode (SC-ISE). The electrode was prepared by adding the PtNPs as an intermediate layer between the ionophore-doped solvent polymeric membrane and the electrical conductor. The PtNPs layer was characterized by high resolution transmission electron microscopy, selected area electron diffraction and X-ray photoelectron spectroscopy. The stability of the electrical potential of the new solid-contact electrode was examined by performing current-reversal chronopotentiometry while the influence of the interfacial water film was assessed by the potentiometric aqueous-layer test. The performance of the new electrode was evaluated by determining K(+). The new electrode presented a Nernstian slope, a very good reproducibility of the standard potential values and a small potential drift.