Yazar "Karagözler, AE" seçeneğine göre listele

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    Investigation of polymerization parameters affecting dopamine selectivity of a polymeric membrane
    (Springer-Verlag, 2000) Ekinci, E; Erdogdu, G; Karagözler, AE
    By means of electrochemical oxidative polymerization, poly (1,3-phenylenediamine) films on a gold electrode were prepared at a potential of 0.8 V. The permeation properties of polymeric films at the different thickness were investigated by cyclic and differential pulse voltammetry techniques. Voltammetric studies showed that polymeric film at the 1.2 mC thickness exhibited selective permeation for dopamine while rejecting ascorbic acid. Then, all the polymerization parameters affecting the permselective characteristics were systematically investigated and the optimal values were determined. Moreover, stability of polymeric membrane was examined. The results showed that polymeric membrane, owing to permselective character, could be used as a dopamine selective membrane.
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    Preparation and electrochemical behavior of dopamine -: selective polymeric membrane
    (Springer Verlag, 2000) Erdogdu, G; Ekinci, E; Karagözler, AE
    o-toluidine was polymerized electrochemically using constant-potential electrolysis at a gold electrode surface. Electrochemical behavior of dopamine and ascorbic acid at the polymer electrode prepared in this manner was examined by cyclic and differential pulse voltammetry techniques. The influence of chemical and electrochemical variables on dopamine selectivity of the polymer electrode was systematically investigated and the optimal values for each parameter were determined. Experimental results showed that optimized polymeric membrane exhibited selectivity for dopamine while blocking ascorbic acid. Therefore, it is claimed that poly (o-toluidine) film can be used as a dopamine-selective polymeric membrane in the presence of ascorbic acid.
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    Preparation, optimization, and voltammetric characteristics of poly(o-phenylenediamine) film as a dopamine-selective polymeric membrane
    (John Wiley & Sons Inc, 2001) Ekinci, E; Erdogdu, G; Karagözler, AE
    Poly(o-phenylenediamine) films were electrochemically prepared on gold electrodes from the corresponding monomer in an aqueous solution at a constant potential. The polymeric films prepared in this one-step procedure were found to be thin and insoluble in the aqueous solution. Cyclic and differential pulse voltammetric techniques were used to examine the permeation properties of ascorbic acid and dopamine at the resultant polymeric film electrode. Then, the effects of the chemical and electrochemical variables (e.g., film thickness, polymerization potential, concentrations of monomer and electrolyte) on the permselectivity characteristics of the polymeric film were systematically investigated and the optimal values for each parameter were determined. Furthermore, it was found that the optimized polymer electrode was found to be stable for the successive runs. As a result, it is claimed that poly(o- phenylenediamine) film can be used as a dopamine-selective polymeric membrane. (C) 2000 John Wiley & Sons, Inc.
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    Voltammetric determination of timolol maleate
    (Maik Nauka/Interperiodica, 2001) Türkdemir, MH; Erdögdu, G; Aydemir, T; Karagözler, AA; Karagözler, AE
    Timolol as a beta -adrenoceptor antagonist is a potent antihypertensive and antianginal drug, which was also proved to be effective for the secondary prevention of myocardial infarction. The analysis of timolol, as with other oxprenolols, in ophthalmic solutions and biological liquids using sensitive instrumental methods has gained importance. Investigation of the electrochemical behavior of timolol maleate on a mercury drop electrode reveals the presence of a specific reduction peak of analytical significance. Analysis conditions affecting the properties of this peak were optimized by a systematic study. The limit of detection of about 2.5 ppb, obtained for the DPV technique using SMDE, is comparable with the most sensitive techniques. This method is suitable for routine analysis in that it is simpler and requires no preconcentration step for the analysis of therapeutic doses of the drug.