1,721,028 research outputs found
Au Nanoparticles in Electroanalysis
No full textThe review presents an overview on the use of electrode surfaces modified by Au nanoparticles in electroanalysis. These devicesresult very promising for the development of amperometric sensors and biosensors capable to quantify different inorganic,organic and biological analytes with extraordinary high sensitivity and low detection limi
Functional Materials in Amperometric Sensing. Polymeric, Inorganic, and Nanocomposite Materials for Modified Electrodes Series: Monographs in Electrochemistry
No full textAmperometric sensors, biosensors included, particularly rely on suitable electrode materials. Progress in material science has led to a wide variety of options that are available today. For the first time, these novel functional electrode coating materials are reviewed in this monograph, written by and for electroanalytical chemists. This includes intrinsically conducting, redox and ion-exchange polymers, metal and carbon nanostructures, silica based materials. Monolayers and relatively thick films are considered. The authors critically discuss preparation methods, in addition to chemical and physical characteristics of these new materials. They present various examples of emerging applications in electroanalysis. Due to its comprehensive coverage, the book will become an indispensable source for researchers working on the development and even proper use of new amperometric sensor systems
Studies of the interface of conducting polymers with inorganic surfaces
No full textMany of the properties of multi-material systems and relevant devices depend on the interfaces between the different components. This review focuses on characteriza- tion of the interfaces between intrinsically conducting poly- mers and inorganic materials consisting of metals and metal oxides. These materials are chosen because of their impor- tance in several analytical applications. Although use of conducting polymers and metals or metal oxides in analyt- ical systems, specifically in sensing, is well established, the number of novel materials used for analytical purposes is continuously increasing. This further increases the possible number of effective combinations of different materials within multicomponent systems. As a consequence, innova- tive characterization techniques have become as important as more conventional techniques. On the other hand, sophis- ticated characterisation techniques are increasingly wide- spread and, consequently, also readily accessible. This critical review is not an exhaustive discussion of all possible analytical techniques suitable for characterization of interfaces. It is, instead, limited to an overview of the most effective, relatively widespread techniques, emphasising their most significant recent advances. Critical analysis of the individual techniques is complemented by a few selected examples
Polythiophenes and polythiophene-based composites in amperometric sensing
No full textAn overview of the polythiophene-based materials introduces the critical exam of meaningful examples of applications of similar electrode materials in electroanalysis. The advantages arising from the use of polythiophene derivatives in such an applicative context is discussed, by considering the organic conductive material as such, and as one of the components of hybrid materials. The rationale at the basis of the combination of two or even more individual components into a hybrid material is discussed with reference to the active electrode processes and to the consequent possible improvements of the electroanalytical performance. With this respect, study cases are presented, considering different analytes, chosen among those that are most frequently reported within the classes of organics and inorganics. The use of a polythiophene matrix to stably fix biological elements at the electrode surface, for the development of catalytic biosensors and genosensors, is also discussed. Finally, a few possible lines along which the next researches in the field could be fruitfully addressed, are outlined. On the other hand, the work still to do in order to exploit the possibilities offered by novel products of organic synthesis, even along paths already traced in other fields of electrochemistry, is invoked
Composite electrode coatings in amperometric sensors. Effects of differently encapsulated gold nanoparticles in poly(3,4-ethylendioxythiophene) system
No full textComposite materials consisting of poly(3,4-ethylendioxythiophene) including Au nanoparticles have been synthesised in order to develop new amperometric sensors with improved performances with respect to bare and to pure organic modified electrodes. The composite materials were prepared by including Au nanoparticles during the electropolymerisation process, by taking advantages to the anionic nature of the species surrounding the metal core. The resulting modified electrodes are found to preserve the repeatability and reproducibility of pure organic modified electrodes and to improve the selectivity toward anionic and cationic species chosen as the benchmark analytes, namely ascorbic acid and dopamine, respectively
The evolution of amperometric sensing from the bare to the modified electrode systems
No full textThe article aims at giving a critical overview ofthe passage from bare to modified electrode systems,proposed for amperometric sensing. An introduction ismade with reference to the development of modifiedelectrodes since the beginning, i.e. from the 1970s. Asubsequent time border is arbitrarily identified around themiddle of 1990s. Since those years, many novelties, comingin part from chemistry and in big part from physics andengineering, induced deep changes in the approach to theelectroanalytical research; they are tentatively outlined. Theterm “research” is intentionally used to underline that wideroom is still available to applications, waiting for efforts byelectrochemists. It is also emphasised that the nature of themodifying systems has been only occasionally tailor-made,i.e. designed and developed on purpose. A strict enoughconnection between the electrochemists and the chemistsexpert in synthesis has been and still is often scarce. Thisnotwithstanding, the number of novel potentially interestingmaterials suitable to develop electroanalytical systemshighly effective in applications is so high that the nextfuture of electroanalysis seems definitely promising. A briefcritical analysis of electrode systems based on similarmaterials is made
Influence of the nature of the supporting electrolyte on the formation of poly[4,4'-bis(butylsulphanyl)-2,2'-bithiophene] films. A role for both counter-ion and co-ion in the polymer growth and p-doping processes
No full textElectrode deposits of a polythiophene with particularly interesting characteristics, i.e., poly[4,40-bis(butylsulphanyl)-2,20-bithiophene],have been generated in the presence of different supporting electrolytes. The formation of the coatings has been studied bycoupling conventional electrochemical techniques with quartz crystal microbalance measurements. The results of simultaneousvoltammetric or chronoamperometric and microgravimetric experiments allow us to show the influence exerted by the nature of thesupporting electrolyte on the polymerisation and concomitant charging–discharging processes of the conducting polymer
Sensori Amperometrici. Nuoivi materiali elettrodici
No full textThe article concerns the development of new materials for electrode systems. A complete characterisation of the materials and of the electrochemical systems is obtained by combiningthe results from different spectroscopic and electrochemical techniques. The resulting modified electrodes are tested as amperometric sensors. A particularly attractive applicationof these devices, even using (ultra)microelectrodes, is in the field of “blind analysis”, as elements of electronic tongues for the classification of real matrices
Electrochemical, Spectroscopic and Microscopic Characterisation of Novel Poly(3,4-ethylenedioxythiophene)/Gold Nanoparticles Composite Materials.
No full textComposite materials consisting of poly(3,4-ethylenedioxithiophene) including Au nanoparticles encapsulatedby bulky anionic species have been electrogenerated and characterised through spectroscopic andmicroscopic techniques. The properties of electrodes modified by similar materials have been studiedwith respect to the oxidation of different benchmark electroactive species, such as negatively chargedascorbic and uric acids, and positively charged dopamine. The responses obtained evidence the dependenceof sensitivity and selectivity of the electrochemical responses on the presence and density of thenanoparticles and on the nature of the relevant encapsulating agent. In particular, the insertion of negativelycharged NPs activates a sort of electrostatic shield toward negatively charged molecules; however,also positively charged species result to be conditioned in accessing the redox active centres, locatedeither on the nanoparticle’s surface or on the conducting polymer’s molecules
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