Publikační činnost akademických pracovníků UPCE / UPCE Research Outputs
Permanentní URI k tomuto záznamuhttps://hdl.handle.net/10195/34541
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Článekpeer-reviewedpublished Otevřený přístup Determination of caffeine at unmodified carbon paste electrode(University of Pardubice, 2013) Stočes, Matěj; Kosová, Lucie; Švancara, IvanIn this paper, electrochemical and electroanalytical characterization of caffeine has been carried out, for the first time, with unmodified carbon paste electrode and in combination with cyclic voltammetry and square-wave voltammetry as the measuring techniques of choice. After defining the proper conditions for the electrode oxidation in highly acidic media and setting the key experimental parameters accordingly, a simple method was subsequently tested on model analyses of real samples (energy and Cola drinks).Článekpeer-reviewedpublished Otevřený přístup Electroanalysis with bismuth- and antimony-film plated carbon paste electrodes in complex-forming and mixed media(University of Pardubice, 2011) Švancara, Ivan; Bartoš, Karel; Stočes, MatějIn this paper, a new study is presented, concerning the possibilities and limitations of bismuth- and antimony-film plated carbon paste electrodes, BiF-CPE and SbFCPE, in combination with stripping voltammetry and mixed supporting electrolytes containing various complex-forming constituents. The experiments with both BiFCPE and SbF-CPE in solutions containing halides (F–, Cl–, Br–, I–), pseudohalides (SCN–, CNO–, CN–), EDTA, or organic anions (tartrate, citrate) were focused on electroanalytical performance of both electrodes for the determination of Cd2+ and Pb2+ as model ions. Their behaviour was observed and discussed via the effects of the individual media upon the peak characteristics, base-line, as well as the dissolution peak of Bi/Sb. The results obtained have confirmed numerous relations and typical features that can be utilised in practical measurements.Článekpeer-reviewedpublished version Omezený přístup Two Novelties in Ion-pair Formation-based Potentiometric Titrations of Anionic Surfactants(2016) Mikysek, Tomáš; Stočes, Matěj; Vytřas, KarelTwo novel approaches in ion-pair formationbased potentiometric titrations of anionic surfactants are presented. First, a new type of the low ohmic coated-wire ion-selective electrode is introduced; the polymeric membrane containing a plasticizer mixed with carbon powder. Second, didecyldimethylammonium chloride as the cationic titrant is for the first time proposed and applied, providing the titration curves with the highest potential jump.Článekpeer-reviewedpublished version Omezený přístup Electrochemical properties of α-tocopherol in aqueous electrolytes after its previous extraction into the glassy carbon paste from aqueous-acetonic mixture(2016) Sýs, Milan; Metelka, Radovan; Stočes, Matěj; Vytřas, KarelStudy on electrochemical behavior of lipophilic α-tocopherol, which is recognized as the most active form of vitamin E, was performed using extraction voltammetry in solely aqueous supporting electrolytes. In the first step, α-tocopherol was extracted into the silicone oil, acting as a binder of glassy carbon paste electrode, from aqueous-organic mixture. Generally, the extraction into the electrode material was carried out from solution containing 50 µmol dm−3 α-tocopherol and 60 % acetone for period of 240 s and corresponding stirring rate of 400 rpm. Electrochemical study was undertaken subsequently by cyclic voltammetry after placing the electrode in aqueous supporting electrolyte. Due to the accumulation effect of extraction, voltammetric records exhibited intensive current signals in acidic media when compared to those obtained at solid glassy carbon electrode. Investigations revealed a promising application of carbon paste electrodes for sensitive analysis of α-tocopherol or other electroactive lipophilic species after their extractive preconcentration.Článekpeer-reviewedpublished Otevřený přístup Carbon nanotube paste electrode with a bismuth film in anodic stripping voltammetry for the determination of heavy metals(Univerzita Pardubice, 2012) Stočes, Matěj; Mikysek, Tomáš; Švancara, IvanIn this article, a new type of metal-based non-mercury electrode based on carbon nanotubes (both multi-walled and single-walled) paste electrode is introduced and examined for electrochemical stripping analysis of selected heavy metals. All important parameters have been optimized by using Cd(II) and Pb(II) as the model ions by square-wave anodic stripping voltammetry, as well as the role of bismuth concentration. It was found that bismuth coated multi-walled carbon nanotubes paste electrode had exhibited a fine linear response at the μgper-litre concentration level of cadmium and lead.Kapitola knihypeer-reviewedpublished Pouze metadata Graphite powder and related material as the principal components of carbon plastic electrodes(Nova Science Publishers, 2013) Švancara, Ivan; Mikysek, Tomáš; Stočes, Matěj; Ludvík, JiříIn this chapter, graphite in powdered form is presented as the material of choice for the preparation and use of the so-called carbon paste electrodes (CPEs) representing one of the most popular types of electrodes in electrochemical measurements for more than five decades. Starting with a short historical reminiscence, when highlighting also the importance of carbon materials in electrochemistry as such, powdered graphite is presented as particularly suitable material for an endless variety of electrodes, sensors, and detectors; the individual forms having found the widespread use in theoretical electrochemical studies, practical electro analysis, as well as in other instrumental measurements. Special attention is paid to the graphite powder with respect to its applicability in carbon paste mixtures and, subsequently, in the configuration of CPEs. In this respect, classification of traditional types of graphite powders is also given, completed with a survey of related and/or alternate carbonaceous materials whose applicability to the preparation of CPEs has undergone a real boom in the new millennium and, in fact, resulted in a new renaissance of the field. Furthermore, graphite powders (together with related materials) are discussed via physical, physicochemical, and principal electrochemical properties and of similar interest are also the corresponding graphite/carbon paste mixtures, including the experimental know-how on their laboratory preparation and way(s) of housing in specially designed holders and similar assemblies At the end of this section, one special example is included, summarizing for the first time the recently performed studies on less well-known phenomena within the electrochemistry with CPEs – the ohmic resistance of carbon pastes in relation with their structure and behavior. Last but not least, the electrochemistry and electroanalysis with CPEs are briefly surveyed, documenting the versatility of these electrodes in modern instrumental analysis, their adaptability to the present day’s trends, as well as great potential in the future, regardless whether one considers traditional graphite powder-based configurations or mixtures from new alternate materials.Článekpeer-reviewedpublished Otevřený přístup Possibilities and limitations of ionic liquids in electrochemical and electroanalytical measurements (a review)(Univerzita Pardubice, 2010) Weidlich, Tomáš; Stočes, Matěj; Švancara, IvanA review (with 155 refs.) concerning the current achievements and typical trends in the chemistry of (room temperature) ionic liquids, (RT)ILs, with particular emphasis on their applicability in electrochemical and electroanalytical measurements. The latter is documented on a rapid progress of ionic liquid-modified carbon paste electrodes (IL-CPEs), the so-called carbon ionic liquid electrodes (CILEs), and related configurations in the last half-decade, within the period of 2005-2010.Článekpeer-reviewedpublished Otevřený přístup Carbon paste electrodes modified with a reaction product obtained by hydrolysis of an antimony(III) salt(Univerzita Pardubice, 2010) Švancara, Ivan; Florescu, Monica; Stočes, Matěj; Baldrianová, Lucie; Svobodová, Eva; Badea, MihaelaIn this article, a new type of antimony-modified electrode is described based on carbon-paste bulk dispersion of a precipitate obtained by hydrolysis of the respective Sb(III) salt. Subsequently, the resultant electrode (SbOL-CPE in two variants) operated via the antimony film formed in nascenti at the electrode surface was subjected to the basic characterisation with respect to its electroanalytical performance in the anodic stripping voltammetry of six heavy metal ions (Zn2+, Cd2+, Pb2+, Sn2+, In3+, and Tl+). As found out, the electrodes of interest have offered the behaviour and functioning comparable to the two related configurations of antimony film-plated (in situ) and antimony trioxide-modified carbon paste electrodes (SbFCPE and Sb2O3-CPE, respectively). Most importantly, the bulk modification with laboratory-prepared precipitate has been shown sufficiently reliable and the compound itself fairly reducible with stable behaviour; i.e., without need to refine or otherwise specially treat prior to use.Článekpeer-reviewedpublished Otevřený přístup Relation between the composition and properties of carbon nanotubes paste electrodes (CNTPEs)(Univerzita Pardubice, 2010) Mikysek, Tomáš; Stočes, Matěj; Švancara, Ivan; Ludvík, JiříTwo types of carbon pastes were prepared, examined and characterized. Particular attention has been paid to the changes of the ohmic resistance, relative to the dependence on the composition of a carbon nanotubes paste electrode (CNTPE) and the respective constituents used. The results were compared with those of "classic" carbon paste electrode (CPE) based on graphite powder and the differences in physical as well as electrochemical properties were discussed and explained. As found, the most evident difference was in the optimal (applicable, employable) carbon-to-binder ratio of the paste. Whereas the CPE could be used only up to 20% (m/m) of the oil, the CNTPE allowed us to go up to 60% (m/m) of the same binding liquid. Finally, some problems connected with homogeneity and stability of carbon paste mixtures as such are also discussed.Článekpeer-reviewedpublished Otevřený přístup Electrospinning technique for preparation of tin dioxide-based nanofibers(Univerzita Pardubice, 2009) Stočes, Matěj; Phani, Ayalasomayajula Ratna; Metelka, Radovan; Švancara, Ivan; Vytřas, Karel
