Development of cobalt oxide film modified electrode decorated with platinum nanoparticles as a biosensing platform for phenol

###EgeUn###Recently, cobalt oxides attract a special attention mainly due to their excellent electrocatalytic activity towards various compounds. This study concerns with electrochemical preparation of cobalt oxide modified glassy carbon electrodes decorated with platinum nanoparticle in the pursuit of its catalytic applications. The parameters affecting the deposition conditions have been evaluated by monitoring oxygen reduction reaction (ORR) in pH 5.0 acetate buffer. Under optimal conditions, the composite film electrode surface was utilised as a platform forbiosensor development. Polyphenol oxidase enzyme was immobilised onto the electrode surface for phenol detection, and the influence of solution and operational parameters have been investigated. The medium pH and the enzyme amount have been optimised as pH 7.0 and 0.3 mg, respectively. Chronoamperograms were recorded for phenol detection in micromolar levels.Ege Universitesi [17-FEN-061]This work was supported by the Ege Universitesi [17-FEN-061]

Development of pulsed deposited manganese and molybdenum oxide surfaces decorated with platinum nanoparticles and their catalytic application for formaldehyde oxidation

WOS: 000374805300008Manganese and molybdenum mixed oxides were co-deposited in a thin film form by pulsed deposition technique on a glassy carbon substrate, and this mixed oxide film was further decorated with platinum nanoparticles. Formaldehyde, being a candidate for proton exchange membrane fuel cell applications, was chosen as the test material for the catalytic activities of the developed surface in alkaline media. The synergetic effect of the mixed metal oxide deposit incorporating Pt nanoparticles was verified by using different mol ratios of the corresponding metal ions and applying pulsed deposition conditions and under optimized conditions and, resultant oxidation peak has shown a significant increase in the peak current accompanied by the small shift in the peak potential. The modified composite electrodes were characterized by SEM, EDX, XPS and EIS. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TUBITAK 2209]Authors would like to thank to Scientific and Technological Research Council of Turkey TUBITAK 2209 project for financial support

WO3 decorated TiO2 nanotube array electrode: Preparation, characterization and superior photoelectrochemical performance for rhodamine B dye degradation

An efficient photoelectrocatalyst was synthesized by electrochemical deposition of WO3 on the titanium nanotube (TNT) array by subsequent cycling the potential between -0.6 - 1.0 V vs Ag/AgCl. The structural and morphological properties of the electrode obtained (TNT-WO3) was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopic (SEM) techniques and it was revealed that TNT surfaces were successfully decorated by WO3 species without formation of another oxidation species. Then, the photoelectrocatalytic activity of the composite electrode set at 0.2 V (vs Ag/AgCl), was tested under UV light irradiation on the degradation of Methylene blue (MB), Orange G (OG) and Rhodamine B (RhB), as the model pollutants. Among the azo dyes studied, the electrode has given the best performance against RhB in comparison to the bare TNT electrode. The influence of the deposition conditions on the efficiency was examined and under optimal conditions and it was noted that efficient removal of the dye can be achieved within 10 min. Another advantage of the composite electrode is that PEC performance can be tuned by simply changing the parameters of deposition. (C) 2021 Elsevier B.V. All rights reserved.This study was supported by Ege University Scientific Research project no: 2018/FEN/036.Ege University Scientific Research project [2018/FEN/036

Preparation and characterization of sodium dodecyl sulfate doped polypyrrole solid phase micro extraction fiber and its application to endocrine disruptor pesticide analysis

WOS: 000320085300015PubMed ID: 23669608A robust in house solid-phase micro extraction (SPME) surface has been developed for the headspace (HS)-SPME determination of endocrine disruptor pesticides, namely, Chlorpyrifos, Penconazole, Procymidone, Bromopropylate and Lambda-Cyhalothrin in wine sample by using sodium dodecylsulfate doped polypyrrole SPME fiber. Pyrrole monomer was electrochemically polymerized on a stainless steel wire in laboratory conditions in virtue of diminishing the cost and enhancing the analyte retention on its surface to exert better selectivity and hence the developed polymerized surface could offer to analyst to exploit it as a fiber in headspace SPME analysis. The parameters, mainly, adsorption temperature and time, desorption temperature, stirring rate and salt amount were optimized to be as 70 degrees C and 45 min, 200 degrees C, 600 rpm and 10 g L-1, respectively. Limit of detection was estimated in the range of 0.073-1.659 ng mL(-1) for the pesticides studied. The developed method was applied in to red wine sample with acceptable recovery values (92-107%) which were obtained for these selected pesticides. (C) 2013 Elsevier B.V. All rights reserved.Ege UniversityEge University [2010/Fen/033]The authors thank to the Ege University for financial support (Project 2010/Fen/033)

Molybdenum oxide/platinum modified glassy carbon electrode: A novel electrocatalytic platform for the monitoring of electrochemical reduction of oxygen and its biosensing applications

WOS: 000321509600046The reduction of oxygen to water is one of the most important reactions in electrochemistry with regards to the wide range of applications in electrocatalysis, metal corrosion, and fuel cell and mostly in biosensor studies. Present study describes the use of a glassy carbon electrode modified with platinum and molybdenum oxide (Pt-MoOx) in strongly acidic solutions for electrocatalytic reduction of oxygen dissolved in buffer solution for the first time. The dispersion of Pt nanoparticles on MoOx provides larger surface area and better electrocatalytic activity for oxygen reduction and the best response toward dissolved oxygen was obtained with a mole ratio of 1: 90 Pt:Mo in deposition solution. The modified surface was then used as a biosensing platform for the monitoring of oxygen consumption due to the bio-catalytic action of glucose oxidase (GO(x)) as the model enzyme. After optimization of the operational conditions, analytical characterization and application of the glucose oxidase GO(x) biosensor to flow injection analysis mode have been successfully performed. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.Ege University (BAP) TurkeyEge University [2010FEN032]This work was supported by the Research Funds of Ege University (BAP) Turkey with 2010FEN032 project number

Polythiophene-Clay Composite Solid-Phase Microextraction Fiber: Preparation, Characterization, and Application to the Determination of Methanol in Biodiesel

9th Aegean Analytical Chemistry Days (AACD) -- SEP 29-OCT 03, 2014 -- Chios, GREECEWOS: 000373911300003A novel polymer-clay composite solid phase microextraction fiber is reported for the adsorption of methanol in biodiesel with subsequent determination by gas chromatography coupled with a flame ionization detector. The fiber was fabricated using a stainless steel wire that was subjected to electropolymerization in 0.1mol NaClO4 containing thiophene and montmorillonite clay dispersed in acetonitrile. Electrochemical deposition was maintained by cycling the potential from -0.2 to +2.2V at a scan rate of 50mV/sec. Examination of the surface by scanning electron microscopy revealed that the fiber had a porous surface suitable for the adsorption of volatile analytes. The properties of the fiber were investigated by thermogravimetric analysis and infrared spectroscopy that showed that the clay was inserted in the structure. The fiber was exposed to methanol in biodiesel. The adsorption time, adsorption temperature, and desorption temperature were optimized. Under the optimized conditions, the linear dynamic range for methanol extended from 0.029 to 0.24% (m/m) with a limit of detection of 0.009% (m/m). The method was employed for the analysis of biodiesel and the results were validated with a standard EN 14110 method

Pyranose oxidase and Pt-MnOx bionanocomposite electrode bridged by ionic liquid for biosensing applications

WOS: 000334753200017Present study reports the use of a glassy carbon electrode modified with manganese oxide decorated with platinum nanoparticles (Pt-MnOx/GCE) for electrocatalytic reduction of oxygen dissolved in buffer solution. The electrode exhibits better electrocatalytic activity toward oxygen reduction than bulk platinum due to larger surface area of manganese oxide which also prevents agglomeration of platinum nanoparticles. Best results were obtained with the electrode modified by cycling the potential in a range of -0.25-1.05 V for five times in a cell containing 1.0 mM K2PtCl6 and 0.1 M MnSO4 in 0.01 M H2SO4 solution. Then, the electrode developed was utilized as a biosensing platform for the monitoring of oxygen consumption due to the bie-catalytic activity of pyranose oxidase. In the pursuit of a stable and rapid response the biocomponent was bridged with an ionic liquid namely 1-butyl-3-methyl imidazolium hexaflourophosphate. Chronoamperometric measurement of oxygen at 0.2 V gave 0.010-0.100 mM linear range with a detection limit of 2.0 mu M and sensitivity of 6.1 nA mu M-1 under optimized conditions. In addition, ionic liquid provides a conductive environment which shortens the response time to 3 s for low concentrations. Overall results indicated that fabricated biosensor is a good candidate for automated systems. (C) 2014 Elsevier B.V. All rights reserved.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); Ege University Research FoundationEge University [2013/FEN/060]This study was supported by TUBITAK 2209 program and Ege University Research Foundation (Project no: 2013/FEN/060)

A novel ethanol biosensor on pulsed deposited MnOx-MoOx electrode decorated with Pt nanoparticles

WOS: 000384010500037Transition metal oxides provide low cost alternatives to noble metals due to their unique electrocatalytic and electrochromic properties and display strong interactions with noble metal nanoparticles. Present study describes the use of mixed molybdenum and manganese oxide film electrode enriched with platinum nanoparticles to enhance the catalytic performance in the oxygen reduction reaction (ORR). The mixed oxide film, denominated as GCE/MnOx-MoOx/Pt, was co-deposited by pulsed potential deposition technique and then, it was used as an immobilization matrix for the intact bacterial cells. The resulted whole cell biosensor has served as a sensing platform for ethanol detection by monitoring of oxygen consumption as a result of the bacterial metabolism in the presence of the substrate. Following the optimization experiments, GCE/MnOx-MoOx/Pt/Gluconobacter oxydans biofilm was applied to investigate the analytical characteristics and response time to ethanol as well as operational stability and substrate specificity for other carbon sources. The linear range was found as 0.075-5.0 mM with a response time of 63 s and the developed method was applied to the ethanol determination in alcoholic drinks. Satisfactory recovery figures were obtained in comparison to the standard method. (C) 2016 Elsevier B.V. All rights reserved