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Pagina personale di Chiara ZANARDI

Dipartimento di Scienze Chimiche e Geologiche
Dipartimento di Scienze Chimiche e Geologiche - Sede Dipartimento di Scienze Chimiche e Geologiche

Ruggeri, S; Terzi, F.; Zanfrognini, B.; Corsi, E.; Dossi, N.; Zanardi, C.; Pigani, L.; Seeber, R. ( 2017 ) - Electroanalytical determination of soluble Mn(II) species at high concentration levels - ELECTROCHIMICA ACTA - n. volume 240 - pp. da 108 a 113 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Glassy carbon electrodes have been successfully employed for the determination, by differential pulse voltammetry, of Mn(II) ions dissolved in aqueous solutions. In particular, a simple and fast procedure also suitable for on-line or at-line process control has been developed. Statistical analysis of the results obtained reveals that the procedure can be adopted in the range 0.59–57.30 mM Mn(II). The electrochemical responses are repeatable and reproducible. Repeatability is testified by the lack of variation of peak current values calculated from 20 subsequent scans carried out at the maximum explored concentration (relative standard deviation <1%). Reproducibility of the responses is supported by the data from the responses on three different electrodes. The proposed procedure does not require any pre-concentration of Mn species at the electrode surface or de-aeration of the solution. By adopting the developed procedure for the analysis, the GC electrode demonstrates to be suitable also for application in real matrices, namely solutions from spent battery recycling; in particular the results from the present electrochemical method are not significantly different from those obtained through inductively plasma coupled mass spectrometry. Interference from other metal species, such as Zn(II) and Fe(III), is negligible. This result is particularly meaningful, since the experimental conditions chosen, implying particularly high concentrations of heavy metals, are representative of those adopted in recovery and recycle processes of Mn species from batteries.

Asir, Suleyman; Zanardi, Chiara; Seeber, Renato; Icil, Huriye ( 2016 ) - A novel unsymmetrically substituted chiral amphiphilic perylene diimide: Synthesis, photophysical and electrochemical properties both in solution and solid state - JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. A, CHEMISTRY - n. volume 318 - pp. da 104 a 113 ISSN: 1010-6030 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A novel unsymmetrically substituted chiral amphiphilic perylene diimide with two different quaternary stereocenters was synthesized. For comparison, symmetrically substituted chiral perylene diimide containing the same quaternary stereocenters was prepared. The dehydroabietylamine was specifically selected in order to minimize stacking properties and maximize solubility. Intermolecular interactions kept under control via l-lysine moiety. The specific optical rotation ([α]D20,alpha) of symmetrically and unsymmetrically substituted perylene dyes measured at 20 °C in chloroform as -105 and +200, respectively. Both of the compounds have excellent solubility in a wide range of organic solvents and symmetrically substituted chiral perylene diimide gives strong fluorescence emission (632 nm) in solid state. Concentration dependent self-aggregation of both compounds results in tunability of fluorescence emission. Compounds are thermally, photophysically and electrochemically stable.

Pigani, Laura; Rioli, Cristina; Foca, Giorgia; Ulrici, Alessandro; Seeber, Renato; Terzi, Fabio; Zanardi, Chiara ( 2016 ) - Determination of polyphenol content and colour index in wines through PEDOT-modified electrodes - ANALYTICAL AND BIOANALYTICAL CHEMISTRY - n. volume 408 - pp. da 1 a 10 ISSN: 1618-2642 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly(3,4-ethylenedioxythiophene)-modified electrodes have been used for the estimation of the polyphenolic content and of the colour index of different samples of wines. Synthetic wine solutions, prepared with different amount of oenocyanins, have been analysed spectrophotometrically and electrochemically in order to find a correlation between the total polyphenolic content or colour index and the current peak. The regression curves obtained have been used as external calibration lines for the analysis of several commercial wines, ranging from white to dark red wines. In this way, a rapid estimation of the total polyphenolic content and of the colour index may be accomplished from a single voltammetric measurement. Furthermore, principal component analysis has also been used to evaluate the effect of total polyphenolic content and colour index on the whole voltammetric signals within a selected potential range, both for the synthetic solutions and for the commercial products.

Seeber, Renato; Zanardi, Chiara; Inzelt, György ( 2016 ) - The inherent coupling of charge transfer and mass transport processes: the curious electrochemical reversibility - CHEMTEXTS - n. volume 2 - pp. da 8 a 8 ISSN: 2199-3793 [Articolo in rivista (262) - Articolo su rivista]
Abstract

As a complement to a previous contribution from us, the mass transport mechanisms of the electroactive species to and from the electrode in an uncomplicated electrode mechanism are considered. The electrode process as a whole is discussed, with emphasis to its reversibility degree, as results from the relevant responses in controlled potential techniques, such as chronoamperometry and current sampling voltammetry, linear sweep and cyclic voltammetry, and in rotating disk voltammetry. The electrode process as a whole, composed by charge transfer and mass transport steps that concur to condition the current flowing, is analysed on the basis of the relative rates of the two steps, as well of the time window within which the process is observed. The so-called 'boundary value problem' for uncomplicated charge transfers with different reversibility degrees is outlined. Supplementary Material is available, in which the simulated concentration profiles for reduced and oxidised species reacting at an electrode, at which a triangular potential waveform is applied, are linked to the corresponding current densities.

Zambianchi, M; Benvenuti, E.; Bettini, C.; Zanardi, C.; Seeber, R.; Gentili, D.; Cavallini, M.; Muccini, M.; Biondo, V.; Soldano, C.; Generali, G.; Toffanin, S.; Melucci, M. ( 2016 ) - Anthracene-based molecular emitters for non-doped deep-blue organic light emitting transistors - JOURNAL OF MATERIALS CHEMISTRY. C - n. volume 4 - pp. da 9411 a 9417 ISSN: 2050-7534 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A new anthracene-based twisted oligomer combining a rigid anthracene-xylene core with diphenylamine ends 4,4′-(anthracene-9,10-diyl)bis(2,5-dimethyl-N,N-diphenylaniline), DiPAXA, is herein presented as an efficient and deep blue emitter material. By exploiting DiPAXA as an emissive layer and 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) as a p-type semiconducting layer, we realize a blue emitting unipolar light emitting transistor (OLET) with a maximum external quantum efficiency (EQE) of 0.13%, a charge mobility up to 0.32 cm2 V-1 s-1 and CIE color coordinates of (0.18, 0.21), i.e. closer to currently available standards (PAL, NTSC). Moreover, comparison with other anthracene-based blue emitters highlights the suitability of this family of twisted anthracene-xylene compounds for unipolar blue OLET applications as a result of the enhanced performances in terms of CIE coordinates and light emission output of newly synthesized DiPAXA.

Zanardi, Chiara; Pigani, Laura; Maccaferri, Giulio; Degli Esposti, Micaela; Fabbri, Paola; Zannini, Paolo; Seeber, Renato ( 2016 ) - Development of a redox polymer based on poly(2-hydroxyethyl methacrylate)for disposable amperometric sensors - ELECTROCHEMISTRY COMMUNICATIONS - n. volume 62 - pp. da 34 a 37 ISSN: 1388-2481 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Membranes based on poly(2-hydroxyethyl methacrylate), chemically modified with ferrocene functionalities, are proposed as novel coatings for the development of disposable amperometric sensors. They are mass-produced on an inert support through an UV photo-induced polymerization, forming self-standing films that can be transferred on an electrode surface. Thanks to the characteristic of the functionalized methacrylate matrix to rapidly and reversibly swell by incorporation of large amounts of water, the ferrocene moieties are in intimate contact with the electrolytic solution. They can activate effective electrocatalytic processes that can be exploited in the field of amperometric sensing. The performance of the methacrylate coating with respect to the determination of hydroquinone benchmark analyte has been tested both in a static solution and in a flux cell.

Palacios-Santander, J.M.; Terzi, F.; Zanardi, C.; Pigani, L.; Cubillana-Aguilera, L.M.; Naranjo-Rodriguez, I.; Seeber, Renato ( 2016 ) - Electrocatalytic and antifouling properties of CeO2-glassy carbon electrodes - JOURNAL OF SOLID STATE ELECTROCHEMISTRY - n. volume 20 - pp. da 3125 a 3131 ISSN: 1432-8488 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Binary metal oxides with different degrees of covalent/ionic character of the oxygen-metal bond are tested as a partial coating of glassy carbon electrode surfaces. The electrocatalytic and antifouling properties of the resulting bicomponent electrode systems are analysed in view of possible applications in different fields of electrochemistry, such as electroremediation and electroanalysis. Based on the performance with respect to oxidation of ascorbic acid, as to sensitivity, repeatability of the responses, and activation of electrocatalytic oxidation, CeO2 has been preferred. This same electrode system has been further studied in respect to a trickier electrochemical process, namely the anodic oxidation of a chlorophenol derivative, which induces massive passivation of bare electrode surfaces. The effectiveness of the bicomponent electrode system in anodic oxidation of 2,4,6-trichlorophenol has been ascertained, over a wide range of concentrations, by comparison with pure glassy carbon surfaces.

Seeber, Renato; Zanardi, Chiara; Inzelt, György ( 2015 ) - Links between electrochemical thermodynamics and kinetics - CHEMTEXTS - n. volume 1 - pp. da 1 a 16 ISSN: 2199-3793 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Redox systems are considered when proceeding (a) in an electrochemical cell (heterogeneous reactions), and (b) in a single compartment (homogeneous reactions), also including the case of a solution in contact with solid phases. Special emphasis is given to the electrochemical systems. Starting from equilibrium states in the individual half-cells, the cell as a whole is (1) made to work spontaneously (batteries, fuel cells) and (2) forced to induce non-spontaneous transformations (electrolysis). Kinetics needs to be considered in both cases: phenomenological aspects and rigorous mathematic tools are intended to concur to draw the picture. Supplementary material is given in order to help visualise what the equations given express.

Seeber, Renato; Pigani, Laura; Terzi, Fabio; Zanardi, Chiara ( 2015 ) - Amperometric sensing. A melting pot for material, electrochemical, and analytical sciences - ELECTROCHIMICA ACTA - n. volume 179 - pp. da 350 a 363 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The critical review discusses the key points of the main blocks leading to the development and use of an amperometric sensing system. On the one side, most attention is paid to the electrode materials that may potentially induce impressive progresses in the performance of the device. On the other side, comparable room is given to the remaining parts constituting the sensing system as a whole, from tests in different solutions to problems arising from data processing. All these steps require care and knowledge of the manifold branches of science and technology that concur to realise and use the device at best. However, some of these aspects are too often underestimated, also due to the different scientific origin of researchers or analysts who are directly involved. The discussion is centred on both the virtues of amperometric sensing systems and on the limits they present. The last are especially evidenced, in order to induce full consciousness of the complexity and interdisciplinary features of this kind of analytical tools. Exemplificative literature dealing with the issues dealt with is cited and critically inserted in the frame of the overall picture.

Arduini, Fabiana; Zanardi, Chiara; Cinti, Stefano; Terzi, Fabio; Moscone, Danila; Palleschi, Giuseppe; Seeber, Renato ( 2015 ) - Effective electrochemical sensor based on screen-printed electrodes modified with a carbon black - Au nanoparticles composite - SENSORS AND ACTUATORS. B, CHEMICAL - n. volume 212 - pp. da 536 a 543 ISSN: 0925-4005 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A screen-printed electrode (SPE) modified with a carbon black (CB)-Au nanoparticles (AuNPs) compositeis assembled and tested. Electrochemical and morphological investigations highlight the physico-chemical properties of the resulting AuNP-CB-SPE amperometric device with respect to SPEs modifiedwith a single component of the nanocomposite. The effective performance of such a modified elec-trode in activating electrocatalytic processes, consisting both in oxidation and reduction reactions, isdemonstrated. In particular, electrochemical tests on analytes such as glucose, hydrogen peroxide, hydro-quinone, and ascorbic acid, evidence that the composite possesses electrocatalytic performance wellsuperior with respect to the relevant mono-component modified SPE. As a consequence, a meaningfullowering of the peak potentials and improvement of the sensor sensitivities is observed when usingAuNP-CB-SPEs with respect to both CB-SPEs and AuNP-SPEs. In the case of H2O2reduction, the occur-rence of the electrochemical process at less negative potentials is coupled to an improvement of sensorsensitivity of about one order of magnitude. Concurrently, lower limit of detections, ranging from 20 to99% less, have been obtained for the major part of the analytes studied, i.e. glucose, hydrogen peroxideand hydroquinone. Preliminary results reported here indicate that AuNP-CB-SPE can be proposed as anefficient amperometric sensor to be used in many analytical applications.

Zanardi, Chiara; Ferrari, Erika; Pigani, Laura; Arduini, Fabiana; Seeber, Renato ( 2015 ) - Development of an Electrochemical Sensor for NADH Determination Based on a Caffeic Acid Redox Mediator Supported on Carbon Black - CHEMOSENSORS - n. volume 3 - pp. da 118 a 128 ISSN: 2227-9040 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Screen-printed electrode (SPE) modified with carbon black nanoparticles (CB) has been tested as a new platform for the stable deposition of caffeic acid (CFA) on the electrode surface. The electrochemical performance from varying the amount of CFA/CB composite has been tested with respect to NADH determination. The electrocatalytic activity of CFA/CB has also been compared with that of SPEs modified by a single component of the coating, i.e., either CFA or CB. Finally, glycerol dehydrogenase, a typical NADH-dependent enzyme, was deposited on the CFA/CB coating in order to test the applicability of the sensor in glycerol determination.

Zanardi, Chiara; Pigani, Laura; Seeber, Renato; Terzi, Fabio; Arduini, Fabiana; Cinti, Stefano; Moscone, Danila; Palleschi, Giuseppe ( 2015 ) - Carbon Black/Gold Nanoparticles Composite for Efficient Amperometric Sensors ( 2nd National Conference on Sensors, 2014 - - 19 February 2014 through 21 February 2014) ( - Sensors: Proceedings of the Second National Conference on Sensors, Rome 19–21 February, 2014 ) (Springer Cham CHE ) - n. volume 319 - pp. da 159 a 163 ISBN: 9783319096162; 9783319096179 | 9783319096179 ISSN: 1876-1100 [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

A screen-printed electrode (SPE) modified with a carbon black and Au nanoparticles bilayer was developed and proposed as an amperometric sensor for ascorbic acid quantification in pharmaceutical products and for dopamine estimation in the presence of large excess of ascorbic acid. Electrochemical investigations highlight the performances of the resulting modified electrode with respect to SPEs modified with a single component of the nano-composite.

Terzi, Fabio; Zanfrognini, Barbara; Ruggeri, Stefano; Maccaferri, Giulio; Pigani, Laura; Zanardi, Chiara; Seeber, Renato ( 2015 ) - Ti metal electrode as an unconventional amperometric sensor for determination of Au(III) species - ANALYTICAL AND BIOANALYTICAL CHEMISTRY - n. volume 407 - pp. da 983 a 990 ISSN: 1618-2642 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The control of the noble metal concentration is crucial in order to increase the efficiency of hydrometallurgic processes in mining and in the recovery of precious materials from electronic waste. The present study is devoted to the development of an effective procedure for the quantification of Au(III) species dissolved in aqueous solutions, similar real complex matrices included. In particular, a novel electrode system based on Ti has been studied. This electrode material is still poorly investigated in the framework of electroanalysis, despite its lack of sensitivity to common interfering species, such as oxygen; hence, the determination of metal species can be carried out without performing deaeration of the solution. In addition, the interfering effect due to the presence of other heavy metal ions, such as Ag, Fe and Pb, has been minimised by a proper choice of the conditions adopted for the amperometric measurements. Ti electrodes exhibit reproducible electrochemical responses, even in the presence of high concentration of organic fouling species typical of biosorption processes.

Terzi, F.; Pigani, L.; Zanardi, C.; Zanfrognini, B.; Ruggeri, S.; Maccaferri, G.; Seeber, R. ( 2014 ) - Novel electrode systems for amperometric sensing: the case of titanium ( Conference on Optics and Photonics for Counterterrorism, Crime Fighting, and Defence X; and Optical Materials and Biomaterials in Security and Defence Systems Technology XI - - SEP 22-23, 2014) ( - OPTICS AND PHOTONICS FOR COUNTERTERRORISM, CRIME FIGHTING, AND DEFENCE X; AND OPTICAL MATERIALS AND BIOMATERIALS IN SECURITY AND DEFENCE SYSTEMS TECHNOLOGY XI ) - n. volume 9253 - pp. da 925313 a 925313 ISBN: 978-1-62841-316-8 ISSN: 1996-756X [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

fter working for years on organic materials, e.g., polythiophenes and relevant composites with metal nanoparticles, we shifted our attention to unusual metals, chosen as candidates to effective amperometric sensing on the basis of the atomic structure and crystalline properties. The present contribution aims at proposing an electrode material rarely employed in electroanalysis, namely Ti. We have experimented that the peculiar nature of Ti leads to electrochemical behavior quite different with respect to the conventional electrode materials, including those based on TiO2 (nano) particles. Our work focuses on the determination of strong oxidizing species, namely H2O2 and HClO, and noble metal ions, namely Au(III). Strong oxidizing species are commodity chemicals employed in a number of different industrial processes, in which usually high concentration levels should be monitored. The procedures proposed have been successfully applied also in complex matrices, such as detergent samples. As to Au(III) determination, it also constitutes a crucial tool in order to increase the efficiency of hydrometallurgic processes and of the recovery of precious materials from electronic waste. Ti electrodes allow the determination of dissolved Au species in the presence of other metal ions. In any cases the electrodes exhibit reproducible and repeatable electrochemical responses, even in the presence of high concentration of organic fouling species typical of bio-sorption processes.

Crespo-Rosa, Joaquin Raphael; Zanardi, Chiara; ElKaoutit, Mohammed; Terzi, Fabio; Seeber, Renato; Naranjo-Rodriguez, Ignacio ( 2014 ) - Electroanalytical applications of a graphite-Au nanoparticles composite included in a sonogel matrix - ELECTROCHIMICA ACTA - n. volume 122 - pp. da 310 a 315 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A novel sonogel composite stably including graphite grains studded with Au nanoparticles (AuNPs) has been synthesised with the aim of obtaining an electrode characterised by electrocatalytic activity, reduced surface passivation and simple and reproducible surface renewal. The impregnation of graphite grains with pre-synthesised AuNPs constitutes a valid approach to stably fix a high amount of AuNPs in such an inorganic matrix. As verified by TEM images, AuNPs fixed on carbon grains surface maintain their individual nature, constituting the basic feature for exerting their electrocatalytic and antifouling properties at best. The electrode was characterised through morphological and electrochemical investigations, demonstrating the uniform distribution of AuNPs on the surface and at different depth of the bulk. Finally, electrochemical tests carried out on the cathodic reduction of H2O2 and on the anodic oxidation of glucose demonstrate the electrocatalytic activity of the AuNPs, the high repeatability of the responses obtained and the reproducibility of the electrode systems, simply restored by routine mechanical cleaning procedure. At variance with many non-enzymatic electrode systems developed for glucose determination, the sensor proposed is suitable for the determination of such a species even at the physiologic neutral pH.

Terzi, F.; Zanfrognini, B.; Pelliciari, J.; Pigani, L.; Zanardi, C.; Seeber, R. ( 2014 ) - Amperometric Determination of Strong Oxidising Species Through Titanium Electrode Systems ( 17th National Conference on Sensors and Microsystems - - 5-7 February 2013) ( - Sensors and Microsystems ) (Springer International Publishing basel CHE ) - n. volume 268 - pp. da 77 a 81 ISBN: 9783319006833 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

The amperometric determination of strong oxidising species has been carried out through an unusual electrode material, namely, Ti. In particular the study involves H2O2 and HClO, even at high concentration levels. A complex real matrix, such as an industrial detergent, containing high H 2O2 concentrations, has been taken as a meaningful study case to check the effectiveness of the electrode system and procedure proposed.

Terzi, Fabio; Zanardi, Chiara ( 2014 ) - Nanosized Materials in Amperometric Sensors ( - Environmental Analysis by Electrochemical Sensors and Biosensors ) (Springer New York USA ) - n. volume Nanostructure Science and Technology - pp. da 497 a 527 ISBN: 978-1-4939-0675-8; 978-1-4939-0676-5 | 978-1-4939-0676-5 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

The use of nanosized materials nowadays constitutes one of the most diffused approach to modify electrode surface when aiming at obtaining efficient amperometric sensors; quite spontaneously, this trend has also involved the field of environmental monitoring. The chapter aims at discussing the properties of nanosized materials, the most widespread strategies for their deposition on the electrode surface as well as the main advantages and limitations of their use in electroanalysis. Metal and carbon nanostructures, and the relevant composite materials, are particularly discussed.

Seeber, Renato; Terzi, Fabio ; Zanardi, Chiara ( 2014 ) - Functional Materials in Amperometric Sensing. Polymeric, Inorganic, and Nanocomposite Materials for Modified Electrodes Series: Monographs in Electrochemistry (Springer Heidelberg DEU ) - pp. da 1 a 223 ISBN: 978-3-662-45103-8 ISSN: - [Monografia o trattato scientifico (276) - Monografia/Trattato scientifico]
Abstract

Amperometric 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.

Fabio Terzi;Laura Pigani;Chiara Zanardi;Barbara Zanfrognini;Renato Seeber ( 2014 ) - Development of Nanostructured Electrode Coatings for Amperometric Sensors ( First National Conference on Sensors - - 15-17 February 2012) ( - Lecture Notes in Electrical EngineeringSensors ) (Springer Science + Business Media New York USA ) - n. volume 162 - pp. da 43 a 48 ISBN: 9781461438595; 9781461438601 | 9781461438601 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

The goal of the communication is to illustrate the main advantages of the use of nanostructured materials as electrode modifiers in the frame of electroanalysis. Particularly meaningful examples extracted from the activity of the research group are discussed. The aim is to evidence the main properties of the single material and the synergic activity deriving from the combination of different materials in hybrids or composites electrode modifiers.

Fabio Terzi;Jonathan Pelliciari; Chiara Zanardi; Laura Pigani; Antti Viinikanoja; Jukka Lukkari; Renato Seeber ( 2013 ) - Graphene-modified electrode. Determination of hydrogen peroxide at high concentrations. - ANALYTICAL AND BIOANALYTICAL CHEMISTRY - n. volume 405 - pp. da 3579 a 3586 ISSN: 1618-2642 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A gold electrode partially coated by graphene multilayer is developed and tested with respect to high concentrations of hydrogen peroxide. The effective use of conventional electrode materials for the determination of such an analyte by anodic oxidation or cathodic reduction is prevented by the occurrence of adsorptions fouling the electrode surface. This prevents reliable and repeatable voltammetric curves for being recorded and serious problems arise in quantitative analysis via amperometry. The gold–graphene electrode is shown to be effective in quantitative evaluation, by cathodic reduction, of hydrogen peroxide at concentration levels that are of interest in an industrial. Acid, neutral, and basic pH values have been tested through correct adjustment of a Britton Robinson buffer. The experiment s have been performed both by cyclic voltammetry and with amperometry at constant potential in unstirred solution. The latter technique has been employed in drawing a calibration linear plot. In particular, the performances of the developed electrode system have been compared with those of both pure gold and pure graphene electrode materials. The bi-component electrode was more sensitive; co-catalytic action by the combination of the two components is hypothesised. The system is stable over many potential cycles, as checked by surface-enhanced Raman spectra recorded over time.

Chiara Zanardi; Luca Ferrari; Barbara Zanfrognini; Laura Pigani; Fabio Terzi; Stefano Cattini; Luigi Rovati; Renato Seeber ( 2013 ) - Development of a Sensor System for the Determination of Sanitary Quality of Grapes. - SENSORS - n. volume 13 - pp. da 4571 a 4580 ISSN: 1424-8220 [Articolo in rivista (262) - Articolo su rivista]
Abstract

An instrument for the automatic quantification of glycerol in grapes has been developed. We verify here that this analyte can be taken as a benchmark of a serious disease affecting the grapevines, namely Botrytis cinerea. The core of the instrument is an amperometric biosensor consisting of a disposable screen printed electrode, generating the analytical signal thanks to a bi-enzymatic process involving glycerol dehydrogenase and diaphorase. The full automation of the analysis is realised by three micropumps and a microprocessor under control of a personal computer. The pumps allow the correct and constant dilution of the grape juice with a buffer solution also containing [Fe(CN)6]4- redox mediator and the injection of NAD+ cofactor when the baseline signal reaches a steady state; the instrument leads to automated reading of the analytical signal and the consequent data treatment. Although the analytical method is based on an amperometric technique that, owing to heavy matrix effects, usually requires an internal calibration, the analyses indicate that a unique external calibration is suitable for giving accurate responses for any grapes, both white and black ones.

Roberta Scanu; Paola Manca; Antonio Zucca; Gavino Sanna; Nadia Spano; Renato Seeber; Chiara Zanardi; Maria I. Pilo ( 2013 ) - Homoleptic Ru(II) complex with terpyridine ligands appended with terthiophene moieties. Synthesis, characterization and electropolymerization - POLYHEDRON - n. volume 49 - pp. da 24 a 28 ISSN: 0277-5387 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A new Ru(II) complex, [Ru(TTT)2][PF6]2 (TTT = 4’-[(2,2’:5’,2”-terthien-3’-yl)methoxy]-2,2’:6’,2”-terpyridine) has been synthesized and characterized by 1H NMR and UV-Vis spectroscopy and by cyclic voltammetry. The electrosynthesis of the corresponding conductive polymer, P[Ru(TTT)2], is reported, as well as its voltammetric and spectroelectrochemical characterization. The comparison between [Ru(TTT)2][PF6]2 and TTT voltammetric data shows that the presence of the metal ion makes easier the oxidation and the polymerization of the organic framework. On the other hand, UV-Vis data confirm that the presence of the –O-CH2-spacer between coordinating and polymerizing unit (terpyridine and terthiophene, respectively) reduces the electronic delocalization among these moieties, analogously to that observed in the TTT ligand alone. As far as P[Ru(TTT)2] is concerned, the voltammetric characterization evidences the so-called ‘charge-trapping phenomena, already observed also in PTTT, too. Moreover, spectroelectrochemical characterization shows a likely overlapping of the p-p* polymer and MLCT complex absorption bands, causing a bathocromic shift with respect to PTTT.

Zanardi, Chiara; Terzi, Fabio; Seeber, Renato ( 2013 ) - Polythiophenes and polythiophene-based composites in amperometric sensing - ANALYTICAL AND BIOANALYTICAL CHEMISTRY - n. volume 405 - pp. da 509 a 531 ISSN: 1618-2642 [Articolo in rivista (262) - Articolo su rivista]
Abstract

An 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.

Fabio Terzi; Jonathan Pelliciari; Barbara Zanfrognini; Laura Pigani; Chiara Zanardi; Renato Seeber ( 2013 ) - Behaviour of Ti electrode in the amperometric determination of high concentrations of strong oxidising species. - ELECTROCHEMISTRY COMMUNICATIONS - n. volume 34 - pp. da 138 a 141 ISSN: 1388-2481 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The study of the capabilities of an unusual electrode material, namely, Ti, is presented: the amperometric determination of species showing responses that, on different materials, cannot be often profitably exploited, is proposed. H2O2 and HClO are successfully analysed, even at high concentrations. In similar conditions, which are quite common in industrial environments, these strong oxidising species are determined by time-consuming, off- or at-line, and multistep procedures. A complex real matrix, such as an industrial detergent, containing high H2O2 concentrations, has been taken as a meaningful study case to check the effectiveness of the electrode system and procedure proposed.

Renato Seeber; Wolfgang Schuhmann; Fabio Terzi; Chiara Zanardi; Nicolas Plumere; Magdalena Gebala ( 2013 ) - Amperometric sensing — Bioelectroanalysis - ANALYTICAL AND BIOANALYTICAL CHEMISTRY - n. volume 405 - pp. da 3423 a 3426 ISSN: 1618-2642 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This editorial introduces to a Special Issue of Analytical and Bioanalytical Chemsitry dedicated to Amperometric Sensing. The progresses made in this scientific field are introduced and critically discussed.

F. Terzi; B. Zanfrognini; C. Zanardi; L. Pigani; R. Seeber ( 2012 ) - Electroreduction of chloramines through novel electrode materials - ELECTROANALYSIS - n. volume 24 - pp. da 833 a 841 ISSN: 1040-0397 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Novel electrode materials have been developed and applied to the determination of chloramines by amperometric methods. In particular, a thin layer of a conducting polymer, namely poly(3,4-ethylenedioxythiophene) (PEDOT) has been tested for the first time in the presence of chloramines. Significant improvements in the performance of the modified electrodes are obtained by using composite materials based on differently encapsulated Au nanoparti-cles and PEDOT. The resulting electrode system exhibits repeatability and reproducibility of the voltammetric re-sponses, as well as low limit of detection and high sensitivity in the determination of monochloramine, as testified by the cyclic voltammetric curves and the calibration plots obtained by a rotating disk electrode.

Zanardi, Chiara; Terzi, Fabio; Seeber, Renato; Bandoli, Clara; Lisandro, Emanuela; Majorana, Stefano ( 2012 ) - Peptide Nucleic Acids tagged with four lysine residues for amperometric genosensors - ARTIFICIAL DNA, PNA & XNA - n. volume 3 - pp. da 80 a 87 ISSN: 1949-095X [Articolo in rivista (262) - Articolo su rivista]
Abstract

A homothymine PNA decamer bearing four lysine residues has been synthesized as a probe for the development of amperometric sensors. The four amino groups introduced, on one hand make this derivative nine times more soluble than the corresponding homothymine PNA decamer and, on the other hand, allow the stable anchoring of this molecule on Au nanostructured surface through the terminal –NH2 moieties. In particular, XPS and electrochemical investigations carried out with hexylamine, as a model molecule, indicate that the stable deposition of primary amine derivatives on such a nanostructured surface is possible and involves the free electron doublet on the nitrogen atom. This finding indicates that this PNA derivative is suitable to act as the probe molecule for the development of amperometric sensors.Thanks to the molecular probe chosen and to the use of a nanostructured surface as the substrate for the sensor assembly, the device proposed makes possible the selective recognition of the target oligonucleotide sequence with very high sensitivity.

Zanardi, Chiara; Bandoli, Clara; Lisandro, Emanuela; Terzi, Fabio; Seeber, Renato ( 2012 ) - Development of a gold-nanostructured surface for amperometric genosensors - JOURNAL OF NANOPARTICLE RESEARCH - n. volume 14 - pp. da 1148 a 1159 ISSN: 1388-0764 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A gold nanostructured surface has been obtained by stable deposition of chemically synthesized gold nanoparticles on a gold substrate, through a dithiol linker. The method proposed for the obtainment of the nanostructure results suitable for the further stable anchoring of peptide nucleic acids (PNA) through four amines from lysine terminal residues, leading to fairly reproducible systems. The geometric area of the nanostructured surface is compared with those of a smooth and of an electrochemical generated nanostructured surface, by depositing a probe bearing an electrochemically active ferrocene residue. Despite the area of the two nanostructures results quite similar, the response toward 2 nM target oligonucleotide sequence is particularly high when using the surface built up by nanoparticles deposition. This aspect indicates that morphologic details of the nanostructure play a key role in conditioning the performances of the genosensors.

B. Zanfrognini; C. Zanardi; F. Terzi; T. Aaritalo; A. Viinikanoja; J. Lukkari; R. Seeber ( 2011 ) - Layer-by-layer deposition of a polythiophene/Au nanoparticles multilayer with effective electrochemical properties - JOURNAL OF SOLID STATE ELECTROCHEMISTRY - n. volume 15 - pp. da 2395 a 2400 ISSN: 1432-8488 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Multilayers consisting of a water soluble polythiophene derivative and Au nanoparticles have been deposited onto different electrode substrates by means of layer-by-layer deposition technique. The assembly of the films has been performed by taking advantage of the electrostatic interactions between the positively charged imidazolic moiety of the polythiophene chain and the negative charges of citrate ions surrounding Au nanoparticles, as well of the affinity of S to Au. The nanoparticles result stably grafted to the organic matrix. The resulting modified electrodes have been characterised through electrochemical, spectroelectrochemical and microscopic techniques. The results evidenced that a high number of individual nanoparticles is present inside the multilayer. The presence of nanoparticles is of chief importance for most effective charge percolation through the multilayer, as suggested by the responses to electroactive probe species in solution. The electrocatalytic performances of the modified electrodes have been tested with respect to the oxidation of ascorbic acid.

B. Zanfrognini; A. Colina; A. Heras; C. Zanardi; R. Seeber; J. López-Palacios ( 2011 ) - A UV-Visible /Raman spectroelectrochemical study of the stability of poly(3,4-ethylendioxythiophene) films - POLYMER DEGRADATION AND STABILITY - n. volume 96 - pp. da 2112 a 2119 ISSN: 0141-3910 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly(3,4-ethylendioxythiophene) films were electropolymerized in aqueous medium without using any surfactant, on glassy carbon electrodes. UV/Vis and Raman spectroelectrochemical techniques were used to analyze the degradation of the polymer film occurring at different pH values. Spectroelectrochemistry has proven to be a very useful analytical tool for this purpose, thanks to its ability to provide information not only about the extent of degradation, but also about mechanistic aspects of t he process. From our results we extracted important information about the main factors that play a role in the degradation, inparticular about the influence of repetitive doping and de-doping cycles and of photo-induced processes, as a function of the characteristics of the solution, i.e. of pH

Fabio Terzi; Barbara Zanfrognini; Chiara Zanardi; Laura Pigani; Renato Seeber ( 2011 ) - Poly(3,4-ethylenedioxythiophene)/Au-nanoparticles composite as electrode coating suitable for electrocatalytic oxidation - ELECTROCHIMICA ACTA - n. volume 56 - pp. da 3575 a 3579 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Composite materials consisting of poly(3,4-ethylenedioxythiophene) including Au nanoparticles, encapsulated by citrate anions, have been firmly deposited on an electrode surface through a simple method, taking advantage of the interaction between Au metal and thiophene polymeric backbone. A series of similar electrode coatings, also including different amounts of nanoparticles inside, has been characterised in terms of thickness and surface morphology, through different microscopic techniques. The electrocatalytic properties have been studied with respect to the oxidation of glucose in alkaline media,which is prevented from occurring on the pure organic material.

Marco Giannetto; Francesca Amico; Giovanni Mori; Fabio Terzi; Chiara Zanardi; Renato Seeber ( 2011 ) - Composite PEDOT/Au Nanoparticles Modified Electrodes for Determination of Mercury at Trace Levels by Anodic Stripping Voltammetry - ELECTROANALYSIS - n. volume 23 - pp. da 456 a 462 ISSN: 1040-0397 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Electrode modifications consisting of poly(3,4-ethylenedioxythiophene) (PEDOT), including gold nanoparticles according to simple though innovative procedure, are developed. The resulting nanocomposite shows interesting performances as electrode material for determination of mercury by anodic stripping technique, even down to concentration levels as low as 0.46 ng/ml. The analytical performance is evaluated by optimized experimental parameters such as the charge spent during the potentiostatic electrodeposition of PEDOT, the preconcentration time, and the waveform parameters for the Differential Pulse Voltammetry (DPV) redissolution scan. No evidence of significant oxidative degradation of the polymer over repeated analysis cycles is evidenced

Fabio Terzi; Chiara Zanardi; Sergio Daolio; Monica Fabrizio; Renato Seeber ( 2011 ) - Au/Pt nanoparticle systems in methanol and carbon monoxide electroxidation - ELECTROCHIMICA ACTA - n. volume 56 - pp. da 3673 a 3678 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Different Au/Pt bimetallic systems have been synthesised by following the approach suggested by Brust. The nanoparticles have been anchored to glassy carbon surface through a place-exchange reaction involving dithiol molecules. The resulting modified electrode consists of heterogeneous nanostructured Au and Pt patchwork. The different nanoparticles systems developed have been employed for the electroxidation of methanol and carbon monoxide in alkaline aqueous media. The results show that the electrocatalytic activity of the bimetallic systems is enhanced with respect to the single monometallic NP systems.

P. Manca; M. I. Pilo; G. Casu; S. Gladiali; G. Sanna; R. Scanu; N. Spano; A. Zucca; C. Zanardi; D. Bagnis; L. Valentini ( 2011 ) - A new terpyridine tethered polythiophene: electrosynthesis and characterisation - JOURNAL OF POLYMER SCIENCE. PART A, POLYMER CHEMISTRY - n. volume 49 - pp. da 3513 a 3523 ISSN: 0887-624X [Articolo in rivista (262) - Articolo su rivista]
Abstract

A novel polythiophene bearing a pendant terpyridine moiety has been synthesized by electrochemical polymerization of a new thiophene monomer, namely 4’-(2,2’:5’,2’’-terthien-3’-ethynyl)-2,2’:6’,2’’-terpyridine (TAT). The insertion of a conjugated ethynyl spacer between the terthiophene and the terpyridine fragments provides for an effective extension of the delocalisation of electrons within the structural unit and the polymer as a whole. The synthesis and characterization of the relevant monomer, the electrosynthesis of the corresponding polymer and its electrochemical, UV-Vis spectroelectrochemical and IR characterization are described. Finally, a comparison between the electrochemical, spectroscopic and spectroelectrochemical properties of PTAT and the analogue, saturated-spacer PTTT (TTT = 4′-[(2,2′:5′,2″-terthien-3′-yl)methoxy]-2,2′:6′,2″-terpyridine) polymer is discussed.

C. Zanardi; F. Terzi ( 2010 ) - Au Nanoparticles in Electroanalysis - LA CHIMICA E L'INDUSTRIA - n. volume 5 - pp. da 140 a 146 ISSN: 0009-4315 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The 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 limit

Zanardi, Chiara; Terzi, Fabio; Zanfrognini, Barbara; Pigani, Laura; Seeber, Renato; Lukkari, J.; Ääritalo, T. ( 2010 ) - Effective catalytic electrode system based on polyviologen and Au nanoparticles multilayer - SENSORS AND ACTUATORS. B, CHEMICAL - n. volume 144 - pp. da 92 a 96 ISSN: 0925-4005 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Au nanoparticles encapsulated by very labile chloride ions are synthesised and characterised. Through layer-by-layer deposition technique they are stably anchored to an electrode surface, using a polyviologen derivative as the polycationic organic component. The structure and morphology of the multilayer is exhaustively studied by UV–vis spectroscopy, X-ray diffraction, scanning and transmission electron microscopy. The nanocomposite material shows very interesting electrocatalytic properties with respect to the reduction of H2O2, which occurs at particularly less negative potentials. Furthermore, the presence of Au nanoparticles inside the electrode coating greatly improves the sensitivity of the electrochemical system. The system results to be a well suitable sensor for H2O2 quantification, with high sensitivity and low detection limit.

Zanardi, Chiara; Terzi, Fabio; Seeber, Renato ( 2010 ) - Composite electrode coatings in amperometric sensors. Effects of differently encapsulated gold nanoparticles in poly(3,4-ethylendioxythiophene) system - SENSORS AND ACTUATORS. B, CHEMICAL - n. volume 148 - pp. da 277 a 282 ISSN: 0925-4005 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Composite 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.

R.Seeber; L.Pigani; C.Zanardi; F.Terzi; B.Zanfrognini ( 2009 ) - Sensori Amperometrici. Nuoivi materiali elettrodici - LA CHIMICA E L'INDUSTRIA - n. volume 2009 - pp. da 82 a 84 ISSN: 0009-4315 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The 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.

Chiara Zanardi; Fabio Terzi; Laura Pigani; Renato Seeber ( 2009 ) - Electrode coatings consisting of polythiophene-based composites containing metal centres. ( - Encyclopedia of Polymer Composites: Properties, Performance and Applications ) (Nova Publishers New York USA ) - pp. da 1 a 74 ISBN: 9781607417170 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

Polythiophene derivatives constitute nowadays the most extensively studied class of conducting polymers, thanks to their mechanical and thermal stability, as well as to their physical and chemical properties, such as electronic conductivity, electrochromism, solvatochromism, thermochromism and luminescence. These materials have been proposed for use in a wide range of applications, including chemical sensors, light emitting diodes, thin film transistors, different electrocatalytic systems, batteries, smart windows, and even artificial muscles.Peculiar systems are realised by anchoring similar materials on substrates. In particular, conductive substrates suitably coated by polythiophene derivatives constitute particularly interesting electrode systems that can be exploited in numerous electrochemical-electroanalytical applications. However, a notable part of the research activity in these fields is today evolving toward the insertion of metals into the polythiophenes matrix, in order to further improve the performances of the pure organic material. The driving force to these studies lies in the possibility to combine the properties of the organic and inorganic entities, taking advantage of their synergic interaction. Basically, two different approaches, resulting in hybrids/composites of quite different nature, have been followed: i) link of metal complexes to the polymeric backbone; ii) inclusion of metal ions and complexes, of clusters, oxides or nanoparticles into the polymer. In similar systems, the presence of the metal is supposed to deeply affect the electronic and electrochemical properties of the resulting hybrid/composite material.The aim of the present contribution is to give a picture of the variety of polythiophene-based hybrid/composite materials developed, with reference to the systems in which the polymer is supported on a conductive substrate, to constitute an electrode system. The different physico-chemical characterisations are treated, mainly devoted to clarify the interactions between the polymer and the metal centres, as well as the nature of the interface between the ambient and the composite as a whole. Description is given of some applications in electrochemical environments.

F. Terzi; C. Zanardi; B. Zanfrognini; L. Pigani; R. Seeber; J. Lukkari; T. Aaritalo; J. Kankare ( 2009 ) - Preparation and Characterization of a RedoxMultilayer Film Containing Au Nanoparticles - JOURNAL OF PHYSICAL CHEMISTRY. C - n. volume 113 - pp. da 4868 a 4874 ISSN: 1932-7447 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Gold nanoparticles encapsulated by negatively charged molecules have been stably anchored at a Au substratethrough layer-by-layer deposition technique, employing a redox polyviologen derivative as the cationiccounterpart. UV-vis spectroscopy, quartz crystal microbalance, transmission electron microscopy, scanningelectron microscopy, atomic force microscopy, and voltammetric measurements have been performed in orderto characterize the systems and to give a rationale to the effect of the deposition conditions on the propertiesof the resulting multilayers. The behavior of two benchmark electroactive species ([Fe(CN)6]4- and[Ru(NH3)6]3+) has been studied on nanoparticle-terminated multilayers. The nanoparticles provide chargepercolation through the multilayer and charge transfer with redox species in solution. The results imply thatthe electrochemical behavior of nanoparticle-containing films is partly dependent on the charge compensationmode within polyelectrolyte multilayers.

L. Pigani; G. Foca; A. Ulrici; K. Ionescu; V. Martina; F. Terzi; M. Vignali; C. Zanardi; R. Seeber ( 2009 ) - Classification of Red Wines by Chemometric Analysis of Voltammetric Signals from Pedot-Modified Electrodes. - ANALYTICA CHIMICA ACTA - n. volume 643 - pp. da 67 a 73 ISSN: 0003-2670 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Nine different types of Italian red wines of four different varieties were analysed, without any samplepre-treatments, by voltammetric techniques using a poly(3,4-ethylenedioxythiophene)-modified electrode.The data matrices consisting of the currents measured at different potentials, by repeated CyclicVoltammetry or Differential Pulse Voltammetry, are submitted to chemometric analysis. After explorativetests based on Principal Component Analysis, Partial Least Squares-Discriminant Analysis classificationmodels are built both for the training and for the test sets. To this aim, different classification strategiesare adopted, considering the responses from the two techniques either separately or joined together toform a data matrix including the whole voltammetric information.

L. PIGANI; G. FOCA; K. IONESCU; V. MARTINA; A. ULRICI; F. TERZI; M. VIGNALI; C. ZANARDI; R. SEEBER ( 2008 ) - Amperometric sensors based on poly(3,4-ethylenedioxythiophene)-modified electrodes: Discrimination of white wines - ANALYTICA CHIMICA ACTA - n. volume 614 - pp. da 213 a 222 ISSN: 0003-2670 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The voltammetric responses on selected white wines of different vintages and origins havebeen systematically collected by three different modified electrodes, in order to check theireffectiveness in performing blind analysis of similar matrices. The electrode modifiers consistof a conducting polymer, namely poly(3,4-ethylenedioxythiophene) (PEDOT) and of compositematerials of Au and Pt nanoparticles embedded in a PEDOT layer. Wine samples havebeen tested, without any prior treatments, with differential pulse voltammetry technique.The subsequent chemometric analysis has been carried out both separately on the signals ofeach sensor, and on the signals of two or even three sensors as a unique set of data, in order tocheck the possible complementarity of the information brought by the different electrodes.After a preliminary inspection by principal component analysis, classification models havebeen built and validated by partial least squares-discriminant analysis. The discriminantcapability has been evaluated in terms of sensitivity and specificity of classification; in allcases quite good results have been obtained.

F. TERZI; C. ZANARDI; V. MARTINA; L. PIGANI; R. SEEBER ( 2008 ) - Electrochemical, Spectroscopic and Microscopic Characterisation of Novel Poly(3,4-ethylenedioxythiophene)/Gold Nanoparticles Composite Materials. - JOURNAL OF ELECTROANALYTICAL CHEMISTRY - n. volume 619-620 - pp. da 75 a 82 ISSN: 1572-6657 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Composite 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.

C.ZANARDI; F.TERZI; L.PIGANI; A.HERAS; A.COLINA; J.LOPEZ-PALACIOS; R. SEEBER ( 2008 ) - Development and characterisation of a novel composite electrode material consisting of poly(3,4-ethylenedioxythiophene) including Au nanoparticles - ELECTROCHIMICA ACTA - n. volume 53 - pp. da 3916 a 3923 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Composite 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.

L. Pigani; M. Musiani; C. Pirvu; F. Terzi; C. Zanardi; R. Seeber ( 2007 ) - Electro-oxidation of chlorophenols on poly (3,4-ethylenedioxythiophene)-poly(styrene sulphonate) composite electrode - ELECTROCHIMICA ACTA - n. volume 52 - pp. da 1910 a 1918 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The electrochemical behaviour of chlorinated phenols on Pt/poly(3,4-ethylenedioxy)thiophene, LiClO4 and on Pt/poly(3,4-ethylenedioxy) thiophene,poly(sodium-4-styrenesulphonate) electrodes has been investigated in phosphate buffer solution. Poly(sodium-4-styrenesulphonate) exerts remarkable effect against the electrode fouling induced by oxidation of chlorophenols, allowing us to record the relevant anodic response even after repeated potential cycles. Hypotheses about the role exerted by poly(sodium 4-styrenesulphonate) are made, on the basis of evidences provided by several techniques, such as cyclic voltammetry, electrochemical impedance spectroscopy, electrochemical microgravimetry and atomic force microscopy. Thanks to the fact that different chlorophenols show differences in the voltammetric responses, depending on number and position of the chloro substituents on the aromatic ring, applications of the modified electrode in the analysis of mixtures of chlorinated phenols are possible. (c) 2006 Elsevier Ltd. All rights reserved.

A. Bello; M. Giannetto; G. Mori; R. Seeber; F. Terzi; C. Zanardi ( 2007 ) - Optimization of the DPV Potential Waveform For Determination of Ascorbic Acid on PEDOT-Modified Electrodes - SENSORS AND ACTUATORS. B, CHEMICAL - n. volume 121 - pp. da 430 a 435 ISSN: 0925-4005 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The electrocatalytic behaviour of poly(3,4-ethylendioxythiophene) (PEDOT) is investigated with respect to detection of ascorbic acid (AA), due to the fundamental importance of such analyte, both for pharmaceutical and food applications.The comparison of the response obtained with ascorbic acid on PEDOT-modified electrodes with Pt-unmodified electrodes resulted particularly interesting: A significant electrocatalytic effect ascribable to the conducting polymer is documented by an anticipated oxidative response of AA, accomplished by a noticeable increase of the anodic peak current. Differential pulse voltammetry (DPV) has been employed as technique for theevaluation of the performance of the CME. The effects of DPV scan parameters on the response of the CME have been studied by means of a 3 factors and 3 levels experimental design. These investigations allowed us to individuate the scan parameters leading to optimal response of the device. The response of CME for AA has been studied by DPV in the optimised conditions, showing good performance in terms of sensitivity and detection limit. A study on the effect of the thickness of the coating has been conducted. The effect of the pH of the solution on the CME response has been also studied.

L. PASQUALI; F. TERZI; C. ZANARDI; R. SEEBER; N. MAHNE; S. NANNARONE ( 2007 ) - Bonding and orientation of 1,4-benzenedimethanethiol on Au(111) prepared from solution and from gas phase - JOURNAL OF PHYSICS. CONDENSED MATTER - n. volume 19 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The orientation and bonding of 1,4-benzenedimethanethiol molecules on Au(111) is studied by means of x-ray and ultraviolet (UV) photoemission, xray absorption and metastable deexcitation spectroscopy. The organic films are prepared both from solution and by exposing the clean substrate to the vapours of the substance in an evacuated environment. This leads to two different growth modes: when self-assembled monolayers (SAMs) are prepared from solution, the molecules tend to form a bilayer film with the molecules standing upright and with the molecular axis forming an angle of about 30 degrees with respect to the substrate normal; when growth is carried out from the gas phase, the molecules tend to assume at the earliest stages of exposure a flat-lying configuration, with both sulfur end-groups bonding to Au; at increasing exposure the surface coverage presents a saturation and the chemisorbed molecules tend to assume an upright arrangement.

L. PASQUALI; F. TERZI; C. ZANARDI; L. PIGANI; R. SEEBER; G. PAOLICELLI; SM SUTURIN; N. MAHNE; S. NANNARONE ( 2007 ) - Structure and properties of 1,4-benzenedimethanethiol films grown from solution on Au(111): An XPS and NEXAFS study - SURFACE SCIENCE - n. volume 601 - pp. da 1419 a 1427 ISSN: 0039-6028 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Core level photoemission and X-ray absorption at the carbon C 1s edge are applied to the study of chemisorption of 1,4-benzenedimethanethiol molecules oil Au(111) and to investigate the effect of the solvent used to prepare the organic films. 1,4-Benzeiledimethanethiol films were prepared in polar and non-polar solvents, i.e. ethanol, methanol and n-hexane. 1,4-Benzenedimethanethiol molecules are anchored to the substrate through a single S-Au bond; the molecules in the films tend to assume an upright orientation, the aromatic ring resulting tilted towards the direction perpendicular to the substrate plane. The films present an effective thickness corresponding to more than a single layer. Only small differences are observed among behaviours in different solvents. It is concluded that the filial properties and conformation of the 1,4-belizenedimethanethiol films are largely determined by the reciprocal interactions between the molecules and with the substrate. (c) 2007 Elsevier B.V. All rights reserved.

V. Martina; K. Ionescu; L. Pigani; F. Terzi; A. Ulrici; C. Zanardi; R. Seeber ( 2007 ) - Development of an electronic tongue based on a PEDOT-modified voltammetric sensor - ANALYTICAL AND BIOANALYTICAL CHEMISTRY - n. volume 387 (6) - pp. da 2101 a 2110 ISSN: 1618-2642 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Three different electrodes were tested for use as nonspecific amperometric sensors for blind analysis on real matrices, namely different fruit juices from different fruits or different brands. The first two electrodes were traditional Pt and Au electrodes, while the third one was modified with poly(3,4-ethylenedioxythiophene) conducting polymer. The sensors were tested separately, tested coupled to each other, and also tested together. The responses of the electrode system(s) were first screened via PCA and then their discriminant capabilities were quantified in terms of the sensitivities and specificities of their corresponding PLS-DA multivariate classification models. Particular attention was paid to analyzing the evolution of the response over subsequent potential sweeps. The modified electrode demonstrated the most discriminating ability, and it was the only system capable of satisfactorily performing the most complex task attempted during the analysis: discriminating between juices from the same fruit but from different brands. Moreover, the electrode cleaning procedure required between two subsequent potential sweeps was much simpler for the modified electrode than for the others. This electrode system was therefore shown to be a good candidate for use as an informative element in an electronic tongue applied to the analysis of other food matrices.

C. Zanardi; R. Scanu; L. Pigani; MI Pilo; G. Sanna; R. Seeber; N. Spano; F. Terzi; A. Zucca ( 2006 ) - Electrochemical and spectroelectrochemical characterisation of poly(3 '-hydroxymethyl-2,2 ': 5 ',2 ''-terthiophene) - SYNTHETIC METALS - n. volume 156 - pp. da 984 a 989 ISSN: 0379-6779 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The electrochemical polymerisation of 3'-hydroxymethyl-2,2':5',2-terthiophene, afforded a new conducting polymer bearing the nucleophilic-CH2OH substituent in beta-position. The characteristics of the system obtained have been defined through electrochemical and spectroelectrochemical techniques, as a function of the nature of the solvent in which polymerisation has been carried out and in which polymer doping is electrochemically induced. Two different morphological and/or structural fractions are obtained when the polymer is electrogenerated in CH3CN solvent, while a more homogeneous deposit, consisting of molecules with shorter conjugation system, forms in CH2Cl2. Marked differences are also evidenced when the polymer is p-doped in the two different solvents.

C. Zanardi; R. Scanu; L. Pigani; M.I. Pilo; G. Sanna; R. Seeber; N. Spano; F. Terzi; A. Zucca ( 2006 ) - Synthesis and electrochemical polymerisation of 3 '-functionalised terthiophenes - Electrochemical and spectroelectrochemical characterisation - ELECTROCHIMICA ACTA - n. volume 51 - pp. da 4859 a 4864 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A new terthienyl derivative, 4-[(2,2:5´,2-terthien-3´-yl)methoxyl-2,2´:6´,2-terpyridine, was synthesised in order to clectrogenerate a new conducting polymer as an electrode coating suitable to complex metal ions. The characteristics of the system obtained have been defined through electrochemical and spectroelectrochernical techniques. The physical and chemical properties of 4´-[(2,2´:5´.2-terthien-3´-yl)methoxy]2,2´: 6´,2-terpyfi dine are compared with those of 3´-hydroxymethyl-2,2´:5´,2-terthiophene, i.e. the corresponding trimer not bearing the terpyridine ligand. Under the same conditions for both monomers, both electrochemical and spectroelectrochentical tests show that 4´-[(2,2´:5´,2-terthien-3´yl)methoxyl-2,2´:6´,2-terpyfidine leads to the formation of a narrower molecular weight distribution, with shorter-conjugated polymer chains.

L. ZOBBI; M. MANNINI; M. PACCHIONI; G. CHASTANET; D. BONACCHI; C. ZANARDI; R. BIAGI; U. DEL PENNINO; D. GATTESCHI; A. CORNIA; R. SESSOLI ( 2005 ) - Isolated single-molecule magnets on native gold - CHEMICAL COMMUNICATIONS - n. volume 12 - pp. da 1640 a 1642 ISSN: 1359-7345 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The incorporation of thioether groups in the structure of a Mn-12 single-molecule magnet, [Mn12O12(L)(16)(H2O)(4)] with L = 4-(methylthio) benzoate, is a successful route to the deposition of well-separated clusters on native gold surfaces and to the addressing of individual molecules by scanning tunnelling microscopy.

S. Lupu; L. Pigani; R. Seeber; F. Terzi; C. Zanardi ( 2005 ) - Study of ultrathin Prussian Blue films using in situ electrochemical surface plasmon resonance - COLLECTION OF CZECHOSLOVAK CHEMICAL COMMUNICATIONS - n. volume 70 - pp. da 154 a 167 ISSN: 0010-0765 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Characterisation of ultrathin Prussian Blue films has been performed using in situ electrochemical surface plasmon resonance technique. Prussian Blue films have been prepared by potentiostatic method on a gold-coated glass surface plasmon resonance sensor. The electrochemical reduction of Prussian Blue to Prussian White and oxidation to Berlin Green are accompanied by a change of the refractive index; the system shows repeating voltammetric responses over subsequent potential cycles. The surface plasmon resonance signal is capable of evidencing minute electrochemically induced changes in the inorganic film coating the electrode.

MA Heras; S. Lupu; L. Pigani; C. Pirvu; R. Seeber; F. Terzi; C. Zanardi ( 2005 ) - A poly(3,4-ethylenedioxythiophene)-poly(styrene sulphonate) composite electrode coating in the electrooxidation of phenol - ELECTROCHIMICA ACTA - n. volume 50 - pp. da 1685 a 1691 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The effectiveness of using conducting polymers as electrode coating material in order to prevent electrode fouling caused by electrochemical oxidation of phenol is investigated. In particular, the use of poly(3,4-ethylenedioxythiophene) (PEDOT) has been tested. Electrode passivation is dramatically reduced while incorporating surfactants containing hydrophilic groups into the polymeric structure. A significant improvement in performance is obtained using poly(sodium 4-styrenesulfonate); its presence in the solution during electropolymerisation leads to successful formation of the composite material. The influence of polymer thickness and of surfactant nature on phenol oxidation is studied in order to obtain repeatable responses for phenol oxidation.

F. TERZI; R. SEEBER; L. PIGANI; C. ZANARDI; L. PASQUALI; S. NANNARONE; M. FABRIZIO; S. DAOLIO ( 2005 ) - 3-methylthiophene Self Assembled Monolayers on planar and nanoparticle Au surfaces - JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL - n. volume 109 - pp. da 19397 a 19402 ISSN: 1520-6106 [Articolo in rivista (262) - Articolo su rivista]
Abstract

In this article the adsorption of 3-methylthiophene on planar and nanoparticle Au surfaces is investigated. The resulting systems are compared with a benchmark system based on 1-decanethiol. The characterization data collected evidence the formation of a packed 3-methylthiophene SAM on the planar surface. In particular, spectroscopic investigations suggest that 3-methylthiophene aromatic system is not adsorbed on the surface through the pi-electron system but rather through the S atom alone. On the other hand, the behavior of 3-methylthiophene on nanoparticle surfaces is notably different from that of the alkanethiol. Only a limited fraction of the surface of Au nanoparticles results to be actually coated after purification; this notwithstanding, the nanoparticle growth seems to be strongly influenced by the presence of such a labile encapsulating agent.

L. ANTOLINI; G. MINGHETTI; A. MUCCI; F. PARENTI; L. PIGANI; G. SANNA; R. SEEBER; C. ZANARDI ( 2005 ) - Palladium(II) derivatives of alkylsulfanyl substituted thiophenes as precursors of inorganic polymers: Spectroscopic, electrochemical investigations and X-ray crystal structure of trans-PdCl2[3-(butylsulfanyl)thiophene](2) - INORGANICA CHIMICA ACTA - n. volume 358 - pp. da 3033 a 3040 ISSN: 0020-1693 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Palladium(II) complexes with two thiophene derivatives bearing alkylsulfanyl chains, i.e., 3-(n-butylsulfanyl)thiophene and 4,4´-bis(n-butylsulfanyl)-2,2´-bithiophene, are synthesised and spectroscopically and electrochemically characterised. The molecular structure of PdCl2[3-(n-butylsulfanyl)thiophene]2 was determined by X-ray analysis. The properties of the complexes have been compared with those of PdCl2[3,3´-bis(n-butylsulfanyl)-2,2´-bithiophene] and of a conductive polymer partially coordinated with Pd(II), previously synthesised by us. We found that Pd(11) ions can coordinate sulfanyl sulfur atoms both in cis and trans configuration, leading to a reticulate material, where some kind of interchain bridging may be reasonably supposed to enhance the bulk conductivity.

L. Pigani; R. Seeber; F. Terzi; C. Zanardi ( 2004 ) - 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 - JOURNAL OF ELECTROANALYTICAL CHEMISTRY - n. volume 562 - pp. da 231 a 239 ISSN: 1572-6657 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Electrode 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.

L.Pigani; R.Seeber; F.Terzi; C.Zanardi ( 2004 ) - EQCM study of the p- and n-doping processes of a poly[4,4’-bis(alkylsulphanyl)-2,2’-bithiophene] - JOURNAL OF ELECTROANALYTICAL CHEMISTRY - n. volume 570 - pp. da 235 a 242 ISSN: 1572-6657 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Electrogenerated deposits of poly[4,40-bis(butylsulphanyl)-2,20-bithiophene] have been characterised in the presence of differentsupporting electrolytes, by coupling current (charge) to microgravimetric measurements from the electrochemical quartz crystal microbalance (EQCM). The simultaneous collection of voltammetric measurements and of data relative to mass changes shows the influence exerted by the nature of the supporting electrolyte on the charge-discharge steps of both p- and n-doping processes. Interestingly, the microgravimetric data collected corresponding to the pre-peaks of both doping processes suggest the occurrence of two opposite motions of ions (ingress into and exit out from the polymer) in the relevant potential region, giving a contribution to the study of the ‘residual charge’ phenomenon.

M. COCCHI; G.C. FRANCHINI; A. MARCHETTI; L. PIGANI; R. SEEBER; L. TASSI; A. ULRICI; C. ZANARDI; P. ZANNINI ( 2004 ) - A study of the dielectric behavior and the liquid structure of a ternary solvent system - ANNALI DI CHIMICA - n. volume 94 - pp. da 165 a 176 ISSN: 0003-4592 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The static dielectric constant of the {DMF(1) + ME(2) + DME(3)} ternary mixtures was measured as a function of temperature (25 less than or equal to t/degreesC less than or equal to 80) and composition, over the whole mole fraction range 0 less than or equal to x(1),x(2),x(3) less than or equal to 1. The experimental values were processed by an empirical equation accounting for the dependence epsilon = epsilon(T, phi(i)), where phi(i) is the volume fraction of the components. A comparison between calculated and experimental data shows that this fitting relationship can be effectively employed to predict epsilon values in correspondence to experimental data gaps. Starting from the experimental measurements, some derived quantities such as molar polarisation (P), and excess counterpart (P-E) were obtained. Both the excess properties, epsilon(E) and P-E, take values partly positive and partly negative under all experimental conditions. The values of the excess quantities are indicative of the presence of specific interactions among different components in the mixtures.

A. ALBERTI; B. BALLARIN; M. GUERRA; D. MACCIANTELLI; A. MUCCI; F. PARENTI; L. SCHENETTI; R. SEEBER; C. ZANARDI ( 2003 ) - Radical ions from 3,3 ''',3 ''''-tris(butylsulfanyl)-2,2 ': 5 ',2 '': 5 '',2 ''',5 ''',2 '''': 5 '''',2 '''''-sexithiophene: An experimental and theoretical study of the p- and n-doped oligomer - CHEMPHYSCHEM - n. volume 4 - pp. da 1216 a 1225 ISSN: 1439-4235 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The 3,3',3' tris(butylsulfanyl)-2,2':5,2:5,2',5',2:5, 2'- sexithiophene 1 was investigated through spectroscopic (NMR, EPR, UV/Vis-NIR), electrochemical, spectroelectrochemical and theoretical (DFT) studies. The charged species obtained upon its oxidation and reduction were characterised, showing that 1 can exist in at least five different oxidation states, that is, a neutral species, a radical cation, a dication, a radical anion, and a dianion. The long term stability of the radical cation 1(+circle) was evidenced by the H-1 NMR study in the presence of small quantities of trifluoroacetic acid (TFA). This approach allowed a comparison of the relative broadening of proton signals of 1, induced by the electron exchange process with traces of radical cation 1(+circle), and the hfc (hyperfine coupling) constants obtained from the EPR study and DFT calculations. In the radical cation, all of the heterocyclic sulphur atoms are not significantly involved in the delocalisation of the unpaired electron, whereas the opposite holds for the radical anion. Time-dependent DFT calculations reproduced well the wavelengths of the optical transitions observed in the spectroelectrochemical experiments for all the five oxidation states and support the formation of the dianion 1(2-).

A. Mucci; F. Parenti; L. Pigani; R. Seeber; C. Zanardi; M. I. Pilo; N. Spano; M. Manassero ( 2003 ) - The effect of Pd(II) coordination on the properties of an alkylsulfanyl substituted polythiophene. Comparison with the corresponding monomer - JOURNAL OF MATERIALS CHEMISTRY - n. volume 13 - pp. da 1287 a 1292 ISSN: 0959-9428 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The synthesis of a conducting polymer partially coordinated with Pd(II) ions is reported. The aim is to study the influence of the metal on the properties of the material as a whole, which is very appealing for possible applications in the field of amperometric sensors. An alkylsulfanyl substituted polythiophene is used in this first approach, due to the well known affinity of the sulfur atom for soft metals. The interaction between the organic and inorganic moieties results in the easy formation of partially coordinated polymer. The presence of the metal ions is found to affect the chemical, physical, and electrochemical properties of the organicmacromolecules, owing to interactions between the polymer p-conjugation system and the metal d orbitals.Synthesis and characterisation of the relevant monomer complex helps to better understand the behaviour of the complex polymer-metal system.

Ballarin B; Facchini M; Lanzi M; Paganin L; Zanardi C ( 2003 ) - Electrochemical synthesis and spectroscopic studies of polyalkylthiophene bearing NLO chromophoric units - JOURNAL OF ELECTROANALYTICAL CHEMISTRY - n. volume 553 - pp. da 97 a 106 ISSN: 1572-6657 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The electrochemical and spectroelectrochemical redox behaviour of two different monomers, suitable for non-linear optical applications. 3-[6-(4-oxy-4'-nitrostilbene)hexyl]thiophene and 3-{6-[4-(4'-nitrophenyl-azo)phenoxy]hexyl}thiophene, are investigated by cyclic voltammetry. In addition the suitable conditions for an electrochemical synthesis of the homopolymer and copolymer with some alkylthiophenes (3-methylthiophene and 3-hexylthiophene) are studied. The polymeric films obtained are characterised by electrochemical methods, spectroelectrochemical UV-vis-NIR and FT-IR in reflectance and compared with the polymer obtained by a chemical method, cast onto Pt and ITO glass surfaces. (C) 2003 Elsevier Science B.V. All rights reserved.

B. BALLARIN; C. ZANARDI; L. SCHENETTI; R. SEEBER; J.L. HIDALGO HIDALGO DE CISNEROS ( 2003 ) - Synthesis and electrochemical characterisation of novel sonogel–carbon–polythiophene microstructured electrodes (Elsevier BV:PO Box 211, 1000 AE Amsterdam Netherlands:011 31 20 4853757, 011 31 20 4853642, 011 31 20 4853641, EMAIL: nlinfo-f@elsevier.nl, INTERNET: http://www.elsevier.nl, Fax: 011 31 20 4853598 Lausanne : Elsevier Sequoia ) - SYNTHETIC METALS - n. volume 139 - pp. da 25 a 33 ISSN: 0379-6779 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A sonogel–carbon–polythiophene microstructured electrode has been synthesised via sonocatalytic procedure. The composite material was characterised by cyclic voltammetry, atomic force microscopy and optical microscopy. A comparison with a similar polythiophene directly cast on a platinum electrode has been made. In contrast with the degrading behaviour (overoxidation) observed at sufficiently positive potentials for alkylsulphanyl substituted polythiophenes cast on the electrode surface, the entrapment of the polymer inside a composite material drastically enhances the stability of the redox-active phase towards irreversible oxidation. In addition, the sonogel–carbon–polythiophene composite represents a good approach to test and, possibly, exploit the electrochemical properties of the polymer which, due to its complete insolubility in the common organic solvents, cannot be adequately cast on an electrode surface or electrosynthesised.

S. Lupu; F. Parenti; L. Pigani; R. Seeber; C. Zanardi ( 2003 ) - Differential pulse techniques on modified conventional-size and microelectrodes. Electroactivity of poly[4,4'-bis(butylsulfanyl)-2,2'-bithiophene] coating towards dopamine and ascorbic acid oxidation. - ELECTROANALYSIS - n. volume 15 - pp. da 715 a 725 ISSN: 1040-0397 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Poly[4,4'-bis(butylsulfanyl)-2,2'-bithiophene] modified conventional-size and (ultra)microelectrodes are first investigated in acetonitrile and quasi-neutral aqueous solution with respect to the repeatability of the responses obtained both in cyclic voltammetry and in differential pulse voltammetry. The reactivity towards ferrocene and hydroquinone, chosen as benchmark oxidizable substances in the two media, respectively, is considered. Comparison is made with the behavior of poly(3-methylthiophene) as electrode coating, which is one of the most commonly used redox mediators in amperometric sensors based on coatings consisting of conducting polymers. The results confirm the appealing properties of poly[4,4'-bis(butylsulfanyl)-2,2'-bithiophene], previously evidenced by us in different electrochemical studies: it exhibits particularly high stability and the characteristics of the current/potential curves obtained make it particularly suitable for analytical purposes. After performing these tests, the quantitative determination of dopamine by modified microelectrode is examined and the simultaneous voltammetric determination of ascorbic acid and dopamine is considered. The possibility of working profitably with a microelectrode at very low buffer-supporting electrolyte concentration is ascertained.

S. LUPU; A. MUCCI; L. PIGANI; R. SEEBER; C. ZANARDI ( 2002 ) - Polythiophene derivative conducting polymer modified electrodes and microelectrodes for determination of ascorbic acid. Effect of possible interferents - ELECTROANALYSIS - n. volume 14 - pp. da 519 a 525 ISSN: 1040-0397 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Conventional-size electrodes and microelectrodes coated by electrogenerated poly[4,4'-bis(butylsulfanyl)-2,2'-bithiophene] have been tested with respect to the electrocatalytic oxidation of a particularly interesting analyte, i.e., ascorbic acid, in different concentrations of phosphate buffer, aqueous solution. Linear sweep and cyclic voltammetry have been used and the quantities related to the analyte concentration were the peak current and the diffusion (t(-1/2)) deconvoluted peak current in the case of conventional-size and of microelectrode, respectively. Fairly good linear correlation could be found; a particularly wide linearity range was obtained by working with the microelectrode. It showed to give good results also at a very low (10(-4) M) phosphate buffer-supporting electrolyte concentration. The actual interference on the analysis of compounds often coupled with ascorbic acid in natural or pharmaceutical products has been studied.

A. Mucci; F. Parenti; L. Pigani; M.I.Pilo; P. Piu; G. Sanna; L. Schenetti; R. Seeber; N. Spano; C. Zanardi ( 2002 ) - Polimeri conduttori coordinati con ioni metallici come nuovi materiali per sensori elettrocatalitici ( XVII Congresso Nazionale di Chimica Analitica - - 24-28 giugno 2002) ( - Atti Del XVII Congresso Nazionale di Chimica Analitica ) (. . ITA ) - n. volume . [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

v. allegato

S. Lupu; C. Mihailciuc; L. Pigani; R. Seeber; N. Totir; C. Zanardi ( 2002 ) - Electrochemical preparation and characterisation of bilayer films composed by Prussian Blue and conducting polymer - ELECTROCHEMISTRY COMMUNICATIONS - n. volume 4 - pp. da 753 a 758 ISSN: 1388-2481 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Preparation and electrochemical behaviour of bilayer films consisting of iron(Ill) hexacyanoferrate, well known as Prussian Blue, and of poly[4,4´-bis(butylsulphanyl)-2,2´-bithiophene], on a platinum electrode, are reported. The electrochemical features of the Prussian Blue/conducting polymer bilayer system are examined in aqueous and acetonitrile solutions. Cyclic voltammetric studies show that, in acetonitrile solvent, the inner layer Prussian Blue is electroactive to some extent, though the electrochemical response of the system is mainly accounted for by poly[4,4´-bis(butylsulphanyl)-2,2´-bithiophene] outer layer. On the other hand, in aqueous solution Prussian Blue exhibits good electroactivity. Under specific experimental conditions, the individual redox behaviour of each constituent of the bilayer is evidenced in the two solvents separately, i.e., that of PB and that of poly[4,4´-bis(butylsulphanyl)-2,2´bithiophene] in aqueous and in organic solvent, respectively. However, interesting reciprocal influences are evident in the current/potential curves recorded under conditions which are discussed.

M. Cocchi; M. Manfredini; A. Marchetti; L. Pigani; R. Seeber; L. Tassi; A. Ulrici; M. Vignali; C. Zanardi; P. Zannini ( 2002 ) - Temperature and composition dependence of the refractive indices of the 2-chloroethanol + 2-methoxyethanol binary mixtures - ANNALI DI CHIMICA - n. volume 92 (3) - pp. da 187 a 201 ISSN: 0003-4592 [Articolo in rivista (262) - Articolo su rivista]
Abstract

AbstractMeasurements of the refractive index n for the binary mixtures 2-chloroethanol + 2-methoxyethanol in the 0 ≤ T/°C ≤ 70 temperature range have been carried out with the purpose of checking the capability of empirical models to express physical quantity as a function of temperature and volume fraction, both separately and together, i.e., in a two independent variables expression. Furthermore, the experimental data have been used to calculate excess properties such as the excess refractive index, the excess molar refraction, and the excess Kirkwood parameter Ag over the whole composition range. The quantities obtained have been discussed and interpreted in terms of the type and nature of the specific intermolecular interactions between the components.

M. Cocchi; G. Franchini; M. Manfredini; A. Marchetti; L. Pigani; R. Seeber; L. Tassi; A. Ulrici; M. Vignali; C. Zanardi; P. Zannini ( 2002 ) - Beta-functionalised polythiophenes as microelectrode modifiers in low conductive media - ANNALI DI CHIMICA - n. volume 92 - pp. da 177 a 185 ISSN: 0003-4592 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A study on polythiophene coated microelectrodes is reported, the goal being that of checking the capability of these electrochemical systems to work in low conductive media. The possibility of electrochemically p-doping the polymer in the presence of very low concentrations or even in the absence of supporting electrolyte in the solution is ascertained, opening the way to the use of similar systems in pure solvent media. This result is obtained in such conditions that the presence of residual charges - and corresponding counterions - trapped inside the film coating can be reasonably hypothesised.

M. COCCHI; M. MANFREDINI; A. MARCHETTI; L. PIGANI; R. SEEBER; L. TASSI; A. ULRICI; C. ZANARDI ( 2002 ) - Viscosity of (ethane-1,2-diol+1,2-dimethoxyethane + water) at temperatures from 263.15 K to 353.15 K - JOURNAL OF CHEMICAL THERMODYNAMICS - n. volume 34 (5) - pp. da 593 a 611 ISSN: 0021-9614 [Articolo in rivista (262) - Articolo su rivista]
Abstract

AbstractThe kinematic viscosity ν for (ethane-1,2-diol + 1,2-dimethoxyethane + water) was measured at 14 different ternary compositions covering the whole miscibility field, and at 19 temperatures in the range 263.15 T / K 353.15. The experimental values were fitted using empirical equations of the type ν = ν (T) and ν = ν (xi), respectively, in order to provide reliable models to account for the behaviour of the system. The excess kinematic viscosity νEhas been determined and interpreted in terms of the type and nature of the interactions among the components of the mixture. Using the experimental ν data, the thermodynamic properties ( ΔG * , ΔH * ,ΔS * ) of the viscous flow have been obtained from the Eyring’s approach and standard thermodynamic equations. Furthermore, excess mixing functions, such asΔG * E , have been determined, and found to evidence the existence of quite strong specific interactions among the components, probably due to the formation of hydrogen bonds and dipolar networks. However, all the calculated excess mixing properties suggest the absence of stable three-component adducts.

M. COCCHI; A. MARCHETTI; L. PIGANI; L. TASSI; A. ULRICI; G. VACCARI; C. ZANARDI ( 2001 ) - Density and volume properties of the 2-methoxyethanol+1,2-dimethoxyethane + water ternary solvent system at various temperatures - PHYSICS AND CHEMISTRY OF LIQUIDS - n. volume 39 - pp. da 151 a 168 ISSN: 0031-9104 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Densities (rho) of the ternary mixtures 2-methoxyethanol + 1,2-dimethoxyethane + water have been measured at 19 temperatures in the range -263.15 less than or equal toT/K less than or equal to 353.15. The experimental data were processed by empirical relations accounting for the dependence of rho on temperature and ternary composition expressed as mole fraction of the components (0 less than or equal to x(i) less than or equal to 1). All checked equations seem to be suitable for correlation purposes, in order to obtain interpolated values in correspondence to experimental data gaps. Furthermore, the excess molar volume (V-E) has been investigated to make evident the possibility of forming stable solvent-cosolvent adducts. The excess property has been interpreted on the basis of specific intermolecular interactions between the components.

H. Ding; Z. Pan; L. Pigani; R. Seeber; C. Zanardi ( 2001 ) - P- and n-doping processes in polythiophene with reduced bandgap. An electrochemical impedance spectroscopy study - ELECTROCHIMICA ACTA - n. volume 46 - pp. da 2721 a 2732 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Electrochemical impedance spectroscopy has been used for the characterisation of electrodes modified with different polythiophenes, namely poly[4,4 ' -bis(butylsulfanyl)-2,2 ' -bithiophene], poly[4,4 ' -bis(methylsulfanyl)-2,2 ' -bithiophene] and poly( 3-methylthiophene), at different applied potentials, using different supporting electrolytes. By comparison of the results obtained under experimental conditions in which n-doping is prevented and those obtained from tests where it does occur, some general features have been deduced. all of them being coherently described by a recently proposed 'generalised transmission line circuit' model: impedance plots at different applied potentials exhibit progressive changes which are well accounted for by the 'evolving' model. The results obtained on the n-doping process of S-alkyl substituted polymers suggest a behaviour interestingly similar to that exhibited in the p-doping: this supports a symmetry that was also found by us in a previous work, with respect to the incorporation and release of counterions during the n- and p-charge-discharge processes.

A. Mucci; F. Parenti; L. Schenetti; R. Seeber; C. Zanardi ( 2001 ) - Politiofeni funzionalizzati con gruppi alchilsulfanilici ( XV Convegno Italiano di Scienza e Tecnologia delle Macromolecole - - 24-27 settembre 2001) ( - Atti del XV Convegno Italiano di Scienza e Tecnologia delle Macromolecole ) (. . ITA ) - n. volume . [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

v.allegato

B. BALLARIN; F. COSTANZO; F. MORI; A. MUCCI; L. PIGANI; L. SCHENETTI; R. SEEBER; D. TONELLI; C. ZANARDI ( 2001 ) - Electropolymerisation and characterisation of poly[4,4 '-bis(butylsulphanyl)-2,2 '-bithiophene] - ELECTROCHIMICA ACTA - n. volume 46 - pp. da 881 a 889 ISSN: 0013-4686 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Electrochemical properties of electrogenerated poly[4,4'-bis(butylsulphanyl)-2.3'-bithiophene] have been studied. with particular attention to the charge-discharge processes. The possibility of both p- and n-doping is indicated. Doping and relevant de-doping processes of the specific polymer have also been considered in the context of the more general, still un-solved problem of the analysis of the mechanisms that al-e operative in the case of simple polythiophenes. In situ spectroelectrochemical measurements have been used to support the electrochemical results and both in situ UV-visible NIR spectroscopy on neutral, p- and n-doped forms of the polymer, and ex situ IR measurements have been performed. (C) 2001 Elsevier Science Ltd. All rights reserved.

A. Mucci; F. Parenti; L. Schenetti; C. Zanardi ( 2001 ) - 4,3'',4''''',4'''''''-Tetrabromo-4',4''',3'''',3''''''-tetra(ottilsulfanil)-2,2':5',2'':5'',2''':5''',2'''':5'''',2''''':5''''',2'''''':5'''''',2'''''''-octatiofene: Sintesi e proprieta' ( XXVII Convegno Nazionale della Divisione di Chimica Organica della Società Chimica Italiana - - 3-7 settembre 2001) ( - XXVII Convegno Nazionale della Divisione di Chimica Organica della Società Chimica Italiana - ATTI ) (Società Chimica Italiana- Divisione di Chimica Organica Trieste ITA ) - n. volume unico [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

E' riportata la sintesi , a partire da un bitiofene asimmetricamente disostituito in 4- e 4'-, di un octatiofene simmetrico sostituito in beta con catene ottilsulfaniliche e atomi di bromo. L'octatiofene, che ha una spiccata tendenza a formare film omogenei, è stato caratterizzato tramite NMR, GPC, UV-Vis.

D. IAROSSI; A. MUCCI; F. PARENTI; L. SCHENETTI; R. SEEBER; C. ZANARDI; A. FORNI; M. TONELLI ( 2001 ) - Synthesis and Spectroscopic and Electrochemical Characterisation of a Conducting Polythiophene Bearing a Chiral β-Substituent: Polymerisation of (+)-4,4′-Bis[(S)-2-methylbutylsulfanyl]-2,2′-bithiophene (Wiley-VCH Verlag GmBH:PO Box 101161, D 69451 Weinheim Germany:011 49 6201 606147, EMAIL: service@wiley-vch.de, INTERNET: http://www.wiley-vch.de, Fax: 011 49 6201 606328 ) - CHEMISTRY-A EUROPEAN JOURNAL - n. volume 7 - pp. da 675 a 685 ISSN: 0947-6539 [Articolo in rivista (262) - Articolo su rivista]
Abstract

A regioregular head-to-head/tail-to-tail poly(b,b'-disubstituted bithiophene) P1 was synthesised by chemical and electrochemical polymerisation of 2,2'-bithiophene that bears (S)-2-methylbutylsulfanyl chains in the b and b'-positions. The polymer was characterised by GPC, NMR and UV/Vis spectroscopy,CD, AFM and by electrochemical and conductivity measurements.The CD spectra of P1 in solutions in which poor solvents are present show interesting features and allow the presenceof different optically active species to be distinguished. Upon varying the casting conditions of P1, different relativeamounts of grainy and homogeneous aggregated phases were observed in AFM micrographies of films and correspondingnegative or positive first Cotton effects were found in the CD spectra. AFM, CD and UV/Vis characterisations were also performed on an electrogenerated optically active polymerPE1, in order to make a comparison with the chemically synthesised one. The interesting, small band gap of P1 allowsfor easy p- and n-electrochemical doping.

A. Mucci; F. Parenti; L. Schenetti; C. Zanardi ( 2001 ) - Bromo- e dibromo-bitiofeni come precursori di bitiofeni beta-funzionalizzati ( 1st Sigma Aldrich Young Chemists Symposium - - 18-19 ottobre 2001) ( - 1st Sigma Aldrich Young Chemists Symposium - 1° SAYCS ) (SAYCS Riccione ITA ) - n. volume unico [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Sono riportate le metodologie sintetiche che permettono di partire da bromo- e dibromo-bitiofeni per ottenere bitiofeni beta-funzionalizzati.

A. Mucci; F. Parenti; L. Schenetti; C. Zanardi ( 2001 ) - Metal-catalised cross coupling of beta-alkylsulfanyl thiophenes ( 3th International School of Organometallic Chemistry - - 9-13 settembre 2001) ( - 3th International School of Organometallic Chemistry ) (Società Chimica Italiana - Gruppo Interdivisionale di Chimica Organometallica Camerino ITA ) - n. volume unico - pp. da 121 a 122 ISBN: ... ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The synthesis of three isomeric bithiophenes via different coupling reactions was reported.

A. MUCCI; F. PARENTI; L. SCHENETTI; C. ZANARDI ( 2001 ) - Beta-Functionalised alpha,alpha'-conjugated oligothiophenes with alkylsulfanyl groups: synthesis and characterisation - TRENDS IN HETEROCYCLIC CHEMISTRY - n. volume 7 - pp. da 55 a 64 ISSN: 0972-432X [Articolo in rivista (262) - Articolo su rivista]
Abstract

alpha-oligothiophenes are important materials for optical and electronic devices and are used as model compounds for the characterization of charge carriers in conjugated chains. The presence of beta-alkylsulfanyl groups on the thiophene ring reduces the band-gap between ground and excited state, and influence the electrical and optical properties in a positive manner in relation to possible applications of these materials. the syntheses of a homologous series of alkylsulfanyl oligothiophenes, up to octithiophenes, is discussed

B. BALLARIN; R. SEEBER; D. TONELLI; C. ZANARDI ( 2000 ) - Anionic clay modified electrode for detection of alcohols. An electrocatalytic amperometric sensor - ELECTROANALYSIS - n. volume 12 - pp. da 434 a 441 ISSN: 1040-0397 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The mechanism of the electrocatalytic oxidation towards a wide series of alcohols, by an electrode covered with the [Ni/Al-Cl] hydrotalcyte-like clay, has been analyzed in the different steps it consists of. Such a clay has been reported to be electrically conductive via a mechanism that shows similarities with that of the redox polymers. The overall process occurs in quite a complicated physical system that is completely different both from a classical electrode-solution one and from an electrode covered with a film of heterogeneous catalyst. By varying the characteristics of the substrate, in terms of steric hindrance and dipole moment of the molecule, the factors affecting the redox mediator-substrate reaction have been studied. The concentration ranges where the amperometric response varies linearly have been determined for the different substrates considered.

H. DING; L. PIGANI; R. SEEBER; C. ZANARDI ( 2000 ) - P- and n-doping of electrochemically formed poly(4,4 '-bisbutylsulfanyl-2,2 '-bithiophene). A novel material with reduced bandgap - JOURNAL OF NEW MATERIALS FOR ELECTROCHEMICAL SYSTEMS - n. volume 3 - pp. da 337 a 341 ISSN: 1480-2422 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Electrodes covered by stable electron conducting polymer films which exhibit easy p- and relatively easy n-doping have been successfully prepared by electrochemical polymerisation of symmetrical 4,4'-bisbutylsulfanyl-2,2'-bithiophene. The whole of the cyclic voltammetric behaviour has been explained based on the concept of 'electrostatically stabilised polarons'.

M. Cocchi; A. Marchetti; L. Pigani; G. Sanna; L. Tassi; A. Ulrici; G. Vaccari; C. Zanardi ( 2000 ) - Density and volumetric properties of ethane-1,2-diol plus di-ethylen-glycol mixtures at different temperatures - FLUID PHASE EQUILIBRIA - n. volume 172 - pp. da 93 a 104 ISSN: 0378-3812 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The density of the ethane-1,2-diol (ED) + di-ethylen-glycol (DEG) binary mixtures has been measured at different temperatures over the complete composition range. The experimental measurements have been used to check the validity of relationships accounting for the dependence of the density on temperature and composition, useful to obtain interpolated values in the correspondence of the experimented data gaps. Starting from the primary data, some derived quantities, such as partial molar volumes, excess and partial excess molar volumes, have been obtained. In these mixtures, V-E presents an S-shaped dependence on composition at each temperature, showing negative values in the ED rich-region and positive values at the opposite extreme. The results are compared and discussed to get light to the: changes in molecular association and structural effects in this solvent system. (C) 2000 Elsevier Science B.V. All rights reserved.

D. Iarossi; A. Mucci; F. Parenti; L. Schenetti; C. Zanardi; A. Forni ( 2000 ) - Poli[4,4'-bis(metilbutilsulfanil)-2,2'-bitiofene]: Sintesi e Proprietà ( XX Congresso Nazionale della Società Chimica Italiana - - 4-9 giugno 2000) ( - XX Congresso Nazionale della Società Chimica Italiana - ATTI ) (Società Chimica Italiana Rimini ITA ) - n. volume unico [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Sono riportate la sintesi e la caratterizzazione del poli[4,4'-bis(metilbutilsulfanil)-2,2'-bitiofene.