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.

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.

A new type of potentiometric solid-state ion-selective electrode (SS-ISE) has been fabricated with an intermediate layer made of 7,7,8,8-tetracyanoquinodimethane (TCNQ) or its ion-radical salts and an ionophore-based ion-selective membrane. To show the influence of the TCNQ layer on electrode selectivity, sodium- and potassium-sensitive membranes were applied. A good Nernstian response with a slope of 59.24 mV/dec in the range from 10(-6.5) to 10(-1) M KCl and 58.68 mV/dec (10(-6) to 10(-1) M NaCl) was observed. The influence of an interfacial water film was assessed by an aqueous-layer test performed during potentiometric measurements. The stability of the electrical potential of the new solid-contact electrodes was tested by performing current-reversal chronopotentiometry, and the capacitance of the electrodes is 132 μF or 154 μF for K(+) and Na(+) solid-contact electrodes. These properties confirmed the analytical applicability of TCNQ-based SC-ISEs and should allow the development of a new solid-state ion sensor group.

No abstract

No abstract

No abstract

The possibility of improving the selectivity of solid-state nitrate-selective electrodes by the application of the tetrathiafulvalene (TTF) or its nitrate salt (TTF(NO 3 )) as an intermediate layer between an electrical conductor and a polymeric membrane is demonstrated. The analytical performance of electrodes was investigated during potentiometric measurements. Fabricated sensors displayed a Nernstian slope (−58.85 mV/decade in the range from 10 −5.0 to 10 −1 M and −59.36 mV/decade in the range from 10 −6.0 to 10 −1 M for TTF− and TTF(NO 3 )−modified electrodes respectively), repeatable and reproducible standard potential and detection limit of 2.5 μM (0.16 mgL −1 ) and 0.63 μM (0.039 mgL −1 ) for TTF− and TTF(NO 3 )−based electrodes, respectively. The selectivity was considerably improved compared to a coated disc electrode or electrodes with intermediate layer based on carbon nanomaterials. Electrical parameters of the proposed sensors were tested by carried out current-reversal chronopotentiometry. In the case of electrodes with the use of TTF or TTF(NO 3 ) the potential drift decreases to 167 μVs −1 or 16.6 μVs −1 and the capacitance is 5.99 μF or 60.3 μF. The proposed sensors were successfully applied in analyzing nitrate concentration in water samples.Nitrates are widely used in the fabrication of fertilizers, drugs, explosives and many products, which significantly contributes to their high concentration in the sewage. 1 The contamination of surface and ground water by nitrate ions is a material problem around the world and their removal is important for two main reasons. This type of water pollution disturbs ecological balance and causes hazard to people health. Nitrates are a source of nitrogen for microbial protein synthesizing, nevertheless excess amount of these ions causes eutrophication in water bodies manifested through uncontrolled growth of algae.The natural level of nitrate in surface water is typically less than 1 mgL −1 due to dilution of surface runoff, plant uptake and denitrification processes. However nitrate pollution has generally increased over time as a result of intensive use of nitrogen fertilizers in agriculture. The maximum acceptable concentration for nitrate has been established at 10 mgL −1 , to be protective of the health. 2,3 Drinking water containing a high concentration of nitrates induces cancer or other health problems, such as the 'blue baby syndrome' in infants. 4 Therefore, it has been necessary to introduce selective, simple and reliable method that could be used for the monitoring the concentrations of nitrates.Several analytical methods for the nitrate determination have been reported including spectrophotometry with the detection limit of 0.031 mgL −1 and 40 μgL −1 , 5,6 chromatography with the detection limit of 0.001 mgL −1 and 0.01 mgL −1 , 7,8 capillary electrophoresis with the detection limit of 0.099 mgL −1 , 9 amperometry with the detection limit of 6.2 ngL −1 , 10 polarography 11 and voltammetry with the detection limit of 5.4 mgL −1 . 12 However, most of ...

No abstract