Generation Of Chemical Sensors Research Articles

Plasmonic Cavity for Self-Powered Chemical Detection and Performance Boosted Surface-Enhanced Raman Scattering Detection.

With the popularization of the Internet of Things, the application of chemical sensors has become more and more extensive. However, it is difficult for a single functional sensor to meet multiple needs at the same time. For the next generation of chemical sensors, in addition to rapid qualitative and quantitative detection, it is also necessary to solve the problem of a distributed sensor power supply. Triboelectric nanogenerator (TENG) and surface-enhanced Raman scattering (SERS) are two emerging technologies that can be used for chemical testing. The combination of TENG and SERS technology is proposed to be an attractive research strategy to implement qualitative and quantitative analysis, as well as self-powered detection in one device. Herein, the Ag nanoparticle (NP)@polydimethylsiloxane (PDMS) plasmonic cavity is demonstrated, which can be exploited not only as a SERS substrate for qualitative analysis of the target molecules but also as a TENG based self-powered chemical sensor for rapid quantitative analysis. More importantly, the as-designed plasmonic cavity enables prolonged triboelectric field generated by the phenomena of triboelectricity, which in turn enhances the "hot spot" intensities from Ag NPs in the cavity and boosts the SERS signals. In this way, the device can have good feasibility and versatility for chemical detection. Specifically, the measurement of the concentration of many analytes can be successfully realized, including ions and small molecules. The results verify that the proposed sensor system has the potential for self-powered chemical sensors for environmental monitoring and analytical chemistry.

Electrochemical Direct Determination of Catecholamines for the Early Detection of Neurodegenerative Diseases

Smart (Nano) materials with biosensing functions posses enormous potential in development of new generation of stable biosensors, chemical sensors, and actuators. Recently, there is a considerable interest in using TiO2 nanostructured materials as a film-forming material since they have high surface area, optical transparency, high bio-compatibility, and relatively good conductivity. In this work, TiO2 nanostructured films were used as nanoporous electrodes to study the electron transfer mechanisms of dopamine. epinephrine and norepinephrine, in order to develop a new generation of chemical sensors. The interesting results obtained are described herein and the analytical characterization of these neurotransmitter sensors is reported.

On the role of individual metal oxide nanowires in the scaling down of chemical sensors

Single-crystalline semiconductor metal oxide nanowires exhibit novel structural and electrical properties attributed to their reduced dimensions, well-defined geometry and the negligible presence of grain boundaries and dislocations in their inside. This favours direct chemical transduction mechanisms at their surfaces upon exposure to gas molecules, making them promising active device elements for a new generation of chemical sensors. Furthermore, metal oxide nanowires can be heated up to the optimal operating temperature for gas sensing applications with extremely low power consumption due to their small mass, giving rise to devices more efficient than their nanoparticle-based counterparts. Here, the current status of development of sensors based on individual metal oxide nanowires is surveyed, and the main technological challenges which act as bottleneck to their potential use in real applications are presented.

An Electrogravimetric Study of an All-Solid-State Potassium Selective Electrode with Prussian Blue as the Electroactive Solid Internal Contact

Due to their fragility, classical ion-selective electrodes (ISEs) can be replaced by a new generation of chemical sensors. In this work, all-solid-state potassium selective electrodes, based on a plasticized poly(vinyl chloride) (PVC) membrane and a Prussian blue film as the solid internal contact, were prepared and characterized. First of all, potentiometric measurements revealed a non-Nernstian response of the electrode. Then, ac electrogravimetric measurements were carried out in KCl solutions under various polarization potentials. It was clearly found that potassium ions enter the PVC membrane regardless of the potential applied. Moreover, small quantities of solvent also enter the membrane at certain studied potentials. Electroacoustic measurements have been also carried out in order to check the validity of Sauerbrey’s law for the quartz crystal microbalance by estimating the electrical characteristics of the quartz resonator under our experimental conditions.

Smart (Nano) materials: TiO 2 nanostructured films to modify electrodes for assembling of new electrochemical probes

Smart (Nano) materials with biosensing functions posses enormous potential in the development of new generation stable biosensors, chemical sensors, and actuators. Recently, there is a considerable interest in using TiO 2 nanostructured materials as a film-forming material since they have high surface area, optical transparency, high bio-compatibility, and relatively good conductivity. In this work, TiO 2 oxides were used as nanoporous electrodes to study the electron transfer mechanisms of H 2O 2, and many interesting biological molecules, as 3,4-dihydroxyphenylacetic acid (DOPAC), ascorbic acid, guanine, l-tyrosine, acetaminophen, and β-NADH, in order to assemble a new generation of chemical sensors and biosensors. A kinetic study was also reported in this paper, which demonstrated high performances towards electrocatalytic processes, obtained at nanostructured TiO 2-modified electrodes.

Polymers for chemical sensing

Chemical sensors play an increasingly important role in monitoring the environment we live in, providing information on industrial manufacturing processes and their emissions, quality control of foods and beverages, and a host of other applications. Electrically conductive plastics are being developed for many useful applications. Improvement in understanding of the physical and chemical mechanisms by which electrical conduction occurs in these materials is now leading to a new generation of chemical sensors, which are reviewed in this article.

Molecular imprints as artificial antibodies — a new generation of chemical sensors

Highly cross-linked polymers containing molecular hollows generated by the method of molecular imprinting are chemically and mechanically stable sensitive materials that are highly suitable for being used in rough environments. We prepared layers also for detection of PAHs in drinking water as to follow engine oil degradation. Different polycyclic aromatic hydrocarbons can be monitored in drinking water down to concentrations of several ng/l by fluorimetric or mass sensitive methods. Even analysis of lubricant degradation processes is possible despite their high complexity: layers imprinted with fresh oil and its used counterpart show selective incorporation of the lubricant they were synthesized with.