Digitální knihovnaUPCE
 

7/2012 Sensing in Electroanalysis

Permanentní URI k tomuto záznamuhttps://hdl.handle.net/10195/56675

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  • Náhled
    ČlánekOtevřený přístuppeer-reviewedpublished
    Determination of carbamate pesticide methomyl using acetylcholinesterase / MWNTs-Chitosan modified glassy carbon electrode
    (Univerzita Pardubice, 2012) Zhao, Yan; Zhang, Shu-Ping; Ma, Jie; Leng, Kai-Liang; Labuda, Jan
    An electrochemical biosensor based on immobilization of acetylcholinesterase (AChE) onto multi-walled carbon nanotubes (MWNTs) and chitosan (CS) modified glassy carbon electrode (GCE) has been prepared for the rapid determination of a carbamate pesticide Methomyl. AChE was immobilized via a layer-by-layer self-assembly modification technique with CS. Inhibition effect of methomyl on the AChE activity was proportional to its concentration within the range from 10-10 to 10-3 g L-1 with the detection limit of 10-11 g L-1. The {AChE/CS}/{MWNTs/CS}/GCE biosensor represents an effective and alternative tool for the determination of pesticide residues in environment and food samples.
  • Náhled
    ČlánekOtevřený přístuppeer-reviewedpublished
    Determination of pesticide chlortoluron using HPLC with amperometric detection at a carbon paste electrode
    (Univerzita Pardubice, 2012) Zavázalová, Jaroslava; Houšková, Lucie; Barek, Jiří; Zima, Jiří; Dejmková, Hana
    Method for the determination of pesticide chlortoluron in environmental samples was developed using HPLC with amperometric detection at the carbon paste electrode based on glassy carbon microparticles. Column LiChroCART® 125-4 Purospher® RP-18 (5 μm) was employed for the separation. Optimum conditions of the determination were mobile phase methanol and Britton-Robinson buffer pH 4.0 (60:40, v/v) and detection potential +1.3 V. Chlortoluron determination was performed in matrices of river water and soil; river water sample was filtered and injected directly; from 2.5 g of soil samples, the analyte was extracted to 5 mL of methanol. This method served well for the separation of the analyte from the matrix interferents and it was possible to determine chlortoluron content above the concentration 0.19 μmol L–1 in the case of river water and 0.29 μg g–1 in the case of soil.
  • Náhled
    ČlánekOtevřený přístuppeer-reviewedpublished
    All-solid Nafion®-based amperometric sensors for monitoring gaseous oxygen
    (Univerzita Pardubice, 2012) Wallgren, K.; Mintsouli, I.; Papadimitriou, S.; Papaderakis, A.; Sotiropoulos, S.
    Oxygen reduction has been studied at three different designs of Au/Nafion®-based all-solid amperometric sensors. These consisted of a planar-type sensor (PTS) with all electrodes sputtered on the same face of the Nafion® membrane, a capillary planar type sensor (CPTS) with the introduction of a cover bearing a capillary, and a sandwich-type sensor (STS) with the working and counter electrode layers deposited on different sides of the polymer electrolyte membrane. The response of all sensors depended heavily on humidity and the degree of Nafion® hydration but, unlike the CPTS and STS configurations, no signs of a limiting current were recorded during voltammetric experiments at an open PTS device, indicating the absence of a significant diffusion barrier in that case. All three simple and inexpensive polymerbased sensors compared well with a commercial fuel cell-type sensor, regarding their response to gaseous oxygen concentration changes.
  • Náhled
    ČlánekOtevřený přístuppeer-reviewedpublished
    Electrochemical DNA biosensors – useful diagnostic tools for the detection of damage to DNA caused by organic xenobiotics (a review)
    (Univerzita Pardubice, 2012) Vyskočil, Vlastimil; Blašková, Marta; Hájková, Andrea; Horáková, Eva; Krejčová, Zuzana; Stávková, Klára; Wang, Joseph
    Supramolecular interactions of various organic xenobiotic compounds with DNA are among the most important aspects of biological studies in clinical analysis, drug discovery, and pharmaceutical development processes. In recent years, there has been a growing interest in the electrochemical investigation of interactions between studied analytes and DNA. Observing the pre- and post-electrochemical signals of DNA or monitoring its interaction with xenobiotics provides good evidence for the interaction mechanism to be elucidated. Such interaction can also be used for sensitive determination of these compounds. This short review should provide evidence that the electrochemical approach brings new insight into human health protection or rational drug design and leads to further understanding of the interaction mechanism between organic xenobiotic compounds and DNA.
  • Náhled
    ČlánekOtevřený přístuppeer-reviewedpublished
    Application of electrochemical sensors for determination of anticholinesterase activity and immobilization of enzyme
    (Univerzita Pardubice, 2012) Vorčáková, Katarína; Štěpánková, Šárka; Zorič, Petra; Sedlák, Miloš; Metelka, Radovan; Vytřas, Karel
    Cholinesterases are important enzymes, which are responsible for the rapid elimination of acetyclholine after its releasing at cholinergic synapses. High activity of cholinesterases is present in patients with Alzheimer´s disease. Therefore, testing of new inhibitors of cholinesterases are important. For determination of the inhibition efficiency several methods can be used. In our case, the anticholinesterase activity expressed by IC50 of five carbamate compounds were tested using screen-printed electrodes and square-wave voltammetry. The next part of our work was focused on testing of two types of immobilization of enzyme on the surface of screen-printed electrodes. Kinetic parameters (Km, Vm) were determined for immobilized and soluted enzyme. Obtained results were disscused.
  • Náhled
    ČlánekOtevřený přístuppeer-reviewedpublished
    Classic and modern methods for detection of serotonin
    (Univerzita Pardubice, 2012) Veregut, Veronica; Florescu, Monica; Badea, Mihaela
    The detection of serotonin and other neurotransmitters from different biological samples (serum, plasma, platelets, urine, saliva, cerebrospinal liquid) are very important in clinical diagnosis. For this reason, several classic and modern methods for detection of serotonin were presented in this paper. The advantages and disadvantages of classic methods (colorimetric, fluorometric, chromatographic methods and immunoassay) were presented. The new methods (sensors, biosensors, imaging techniques - PET) are also indicated. Electrochemical detection of serotonin is indicated in the scientific literature, using different types of electrodes (glassy carbon electrode, screen printed electrode).
  • Náhled
    ČlánekOtevřený přístuppeer-reviewedpublished
    Determination of phosphates and polyphosphates using capillary isotachophoresis
    (Univerzita Pardubice, 2012) Valentová, Tereza; Bartoš, Martin; Mikysek, Tomáš
    In this article, phosphate, di- and triphosphates are the analytes determined in commercially marketed samples with the aid of capillary isotachophoresis. After method development, the optimal electrolyte system comprised 10 mM HCl + β-alanine + 0.1% hydroxy-ethylcellulose (pH 3.6) as the leading electrolyte and 10 mM citric acid as the terminating electrolyte. The calibration / detection characteristics are as follows: linearity over the concentration range of 0–200 mg.l-1 P2O5, limit of detection ca. 0.3 mg.l-1 P2O5, limit of quantification of ca. 1 mg.l-1 P2O5. The time of analysis was from 15 to 30 minutes. Furthermore, relatively simple procedure, low operational costs, and sufficient sensitivity are further positive attributes of the method tested in analyses of selected real samples.
  • Náhled
    ČlánekOtevřený přístuppeer-reviewedpublished
    The lead film electrode prepared with use of the combination of ex-situ and in-situ methods in stripping analysis of folic aci
    (Univerzita Pardubice, 2012) Tyszczuk-Rotko, Katarzyna
    In this article, elaboration of a "hybrid" lead film electrode is reported. The strategy to create such an electrode is based on the combination of ex-situ and in-situ plating methods and also the use of a reversibly deposited metal mediator (Cd) for the lead film formation. Various plating conditions, which influenced the response of the “hybrid” lead film electrode to folic acid, were thoroughly optimized and discussed. The results have indicated that the sensitivity of the “hybrid” lead film electrode prepared with use of the metal mediator was remarkably improved compared to the in-situ and ex-situ plated lead film electrodes, and the “hybrid” lead film electrode prepared without use of the metal mediator could be applied to the determination of folic acid in tablets (preparative Folovit®) with satisfactory results.
  • Náhled
    ČlánekOtevřený přístuppeer-reviewedpublished
    Photolithographically fabricated microelectrodes with interacting diffusion layers: fundamentals and basic applications
    (Univerzita Pardubice, 2012) Tomčík, Peter
    This book chapter describes photolithographically fabricated microelectrodes and their arrays as very perspective tool in contemporary electrochemistry. Photolithographic thin layer technology allows to fabricate an array of sensors of micrometric dimension separated with a very small gap. This fact enables an overlapping of diffusion layers of single microelectrodes as members of the array. Various basic types of microelectrode arrays with interacting diffusion layers are described and their analytical abilities are accented. Theoretical approaches of diffusion layer overlapping and consequences of close constitution effects such as collection efficiency and redox cycling are discussed. Examples of basis applications in electroanalytical chemistry such as amperometric detectors in HPLC and substitutional stripping voltammetry are also given.
  • Náhled
    ČlánekOtevřený přístuppeer-reviewedpublished
    Interference of ascorbic acid in the determination of hydroquinone using an amperometric enzyme biosensor based on carbon paste
    (Univerzita Pardubice, 2012) Sýs, Milan; Pekec, Bruna; Kalcher, Kurt; Ribitsch, Volker; Feketeföldi, Birgit; Vytřas, Karel
    The topic of this work deals with the interference of ascorbic acid in the determination of polyphenols with an amperometric biosensor containing tyrosinase. The sensor was prepared by covering carbon paste with a Nafion-film containing the enzyme. Hydroquinone (benzene-1,4-diol) is a polyphenolic compound which was used as a model one for amperometric measurements. Factors influencing the amperometric response were studied in detail. Optimized conditions for operating the biosensor in hydrodynamic amperometric mode were evaluated.