Yazar "Aksoy, Busra" seçeneğine göre listele
Listeleniyor 1 - 8 / 8
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Development of voltammetric sensor based on polyimide-MWCNT composite membrane for rapid and highly sensitive detection of paracetamol(Elsevier Sci Ltd, 2020) Burc, Muammer; Koytepe, Suleyman; Duran, Serap Titretir; Ayhan, Nurcan; Aksoy, Busra; Seckin, TurgayIn this work, for low level detection of paracetamol (PA) a voltammetric sensor was obtained. Polyimidemultiwall carbon nanotube (PI-MWCNT) composite film was used for modification of platinum (Pt) electrode as selective membrane. Firstly, this PI-MWCNT film was synthesized with 2,5-diaminopyridine (DAP), 4,4'-oxydiphthalic anhydride (ODPA) and MWCNT as a reinforcement by thermal imidization technique. The morphology, micro and chemical structures of the obtained composite film were studied by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and thermal analysis techniques. Then, the paracetamol sensor was prepared via the modification of Pt electrode with prepared PI-MWCNT composite film. Pt electrode was modified by coating with prepared PI-MWCNT composite film. Modified Pt electrode was used as PA sensor due to its selective membrane property in the presence of interfering substances for the electrochemical detection of PA. Electrochemical behaviour of paracetamol at the polyimide film modified Pt electrode was obtained by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) method. It has shown that the modified electrode exhibits remarkable repeatability and precision in analytical paracetamol response as compared with other modified paracetamol electrodes. Comparing the responses of modified electrode with the unmodified Pt electrode, selectivity, sensitivity and stable responses significantly enhanced. A linear calibration plot having a correlation coefficient of 0.997 was obtained in the concentration range from 0.3 to 1.8 mM paracetamol. A linear calibration plot for low concentration area having a correlation coefficient of 0.999 was obtained in the concentration range from 0.002 to 0.05 mM paracetamol. Detection limit (LOD) and quantitative limit (LOQ) for paracetamol detection of PI-MWCNT modified electrode were calculated as 0.002 mM and 0.006 mM respectively. In addition, the presented method was applied for determination of PA in commercial tablets. The recovery efficiency of the PI modified electrode was obtained range of 96% and 102% for three different tablets. As a result; a simple, rapid, low cost, repeatable method showing good accuracy and precision (99.4%) has been developed for the selective and sensitive determination of paracetamol by prepared PI-MWCNT composite film modified electrode. (C) 2019 Elsevier Ltd. All rights reserved.Öğe A novel electrochemical biosensor based on polyimide- boron nitride composite membranes(Taylor & Francis As, 2017) Aksoy, Busra; Pasahan, Aziz; Gungor, Oznur; Koytepe, Suleyman; Seckin, TurgayPolyimide (PI) and polyimide-boron nitride (PI-BN) composites as dopamine-selective membrane were synthesized. The structures of the monomer, pure PI, and PI-BN composites were characterized by FT-IR, SEM, and thermal analysis techniques. Experiment results showed that introduction of BN particles increased porosity, selectivity and improved heat-resistance of polyimide matrix. Selectivity of PI-BN composite membranes toward dopamine and interferences was examined by DPV technique. Electrochemical measurement results illustrated that polyimide membrane containing 5% BN possessed wide linear ranges, excellent sensitivity, selectivity, reversibility, and low detection limits (4 X 10(-8) M). The polyimide membrane was very high R value (0.9904). [GRAPHICS] .Öğe Preparation and properties of selective polyurethane films and their use for the development of biomedical dopamine sensor(Taylor & Francis As, 2016) Savan, Ebru Kuyumcu; Pasahan, Aziz; Aksoy, Busra; Gungor, Oznur; Koytepe, Suleyman; Seckin, TurgayPolyurethane films were synthesized by 3,4-divanillyltetrahydrofuran and different diisocyanates. These prepared polyurethanes were characterized by FT-IR, DSC, DTA, and TGA techniques. For the amperometric applications, synthesized polyurethanes exhibited suitable T-g (degrees C), good thermal stability and good adhesive properties. In addition, because of their interesting film properties, attempts were made to prepare dopamine-sensing electrode. For this reason, selectivity of film-coated electrodes obtained from the chemically prepared polyurethanes toward electroactive and nonelectroactive species were examined by means of DPV technique. From the electrochemical results obtained, it has been demonstrated that the PU-1-coated electrode can be used for the development of biomedical sensor.Öğe Preparation of hybrid PU/PCL fibers from steviol glycosides via electrospinning as a potential wound dressing materials(Wiley, 2020) Mehteroglu, Ezgi; Cakmen, Ayse B.; Aksoy, Busra; Balcioglu, Sevgi; Koytepe, Suleyman; Ates, Burhan; Yilmaz, IsmetIn this study, the synthesis and application of biocompatible steviol glycosides based polyurethane/poly (epsilon-caprolactone) (PU/PCL) fibers was performed by electrospinning as a potential wound dressing materials that can be used for the closure of nonhealing wounds. During electrospinning, steviol glycoside-based polyurethane structures were used in blend formation with poly (epsilon-caprolactone) for easy producibility. Steviol glycosides are a natural abundant and easily accessible source as the main component of the wound dressing material due to their free hydroxyl groups, high biocompatibility, and hydrophilicity. The structure of steviol glycosides is composed of saccharide units and the free OH groups. Thus, steviol glycosides act as a crosslinker within the polyurethane structure and provides mechanical strength. For the production of steviol glycosides based PU/PCL fibers first, the steviol glycosides as a monomer were isolated from the stevia rebudiana. Then, polyurethane structures containing stevia glycoside were synthesized with hexamethylene diisocyanate, lactose and PEG-200 by solution polymerization technique. PCL was added to the prepared polyurethanes in a ratio of 1:2 and formation of nanofiber structure. The prepared wound dressing material was characterized by Fourier transform infrared, atomic force microscopy, and scanning electron microscope techniques. Swelling degree, water content and oxygen permeability assay of the steviol glycosides based PU/PCL wound dressing material was determined. In biocompatibility test, cell viability value of PU/PCL fibrous materials in indirect cytotoxicity test was determined as 86.9% and cell adhesion on hybrid PU/PCL fibers was showed as morphological. In accordance with this target, the steviol glycosides based PU/PCL wound dressing material can be produced easily and low cost. As a result, the wound dressing materials obtained with their high biocompatibility and low costs will be an effective and fast method for the healing of open wounds of diabetics.Öğe Preparation of Novel Sensors Based on Polyimide Membrane for Sensitive and Selective Determination of Dopamine(Taylor & Francis Inc, 2016) Aksoy, Busra; Gungor, Oznur; Koytepe, Suleyman; Seckin, TurgayPolyimides as dopamine selective membrane were prepared from 4,4'-diaminodicyclohexyl-methane and different dianhydrides. The chemical structure and thermal properties of these polyimides were examined. For the voltammetric sensor applications, polyimides exhibited suitable glass transition temperature (T-g), high thermal stability, and good adhesive properties. Moreover, polyimides were coated onto Pt electrode surface for the preparation of dopamine selective electrodes. Electrochemically dopamine responses of polyimide-coated electrodes were examined by differential pulse voltammetry. The sensor characteristics such as sensitivity, linearity, selectivity, response time, and stability of the prepared sensors have been determined. Prepared polyimide-coated electrodes can be used for selective and sensitive dopamine detection.Öğe Preparation of triaminotriazine-based polyimide-modified electrodes and their use for selective detection of catechin in green tea samples(Springer, 2020) Duran, Serap Titretir; Ayhan, Nurcan; Aksoy, Busra; Koytepe, Suleyman; Pasahan, AzizAn effective electrochemical sensor was developed from triaminotriazine-based polyimide (PI) films as selective membrane for the detection of catechin (CT). Firstly, triaminotriazine-based PI films were synthesized from 2,4,6-triamino-1,3,5-triazine (TAT) and pyromellitic dianhydride by thermal imidization method with different monomer ratios. Structural and morphological of synthesized PI films were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy. Prepared polyimide films were used as membrane for the preparation of the modified electrodes. Catechin (CT) selectivity behavior of polyimide-modified Pt electrodes was investigated by means of differential pulse voltammetry (DPV). DPV voltammograms showed that peak currents of the modified electrode increased proportionally with increase in CT concentration. TAT-PI-1/1 sensor showed high selectivity, a high regression coefficient (R value = 0.9982 ), good repeatability (RSD of 2.15%), and limit of detection 0.0152 mM for catechin determination in the presence of multiple interferent species (1 mM coumaric acid, ascorbic acid, gallic acid, lactose, sucrose, fructose, maltose and glucose). Moreover, the TAT-PI-1/1 sensor was employed to determine CT in real sample.Öğe Recent Progress and Perspectives on Polyurethane Membranes in the Development of Gas Sensors(Taylor & Francis Inc, 2021) Aksoy, Busra; Sel, Evren; Kuyumcu Savan, Ebru; Ates, Burhan; Koytepe, SuleymanIn today's technology, gas sensors are of great importance in areas such as assessing environmental impacts, monitoring gas production facilities, measuring natural gas, controlling mines and gas leaks. Improving sensor sensitivity and decreasing the determination time is among the subjects that are continuously investigated. The use of polymeric membranes to make such improvements is common practice in the gas sensor field. By the development of polymeric membrane-based gas sensors and increasing the measurement sensitivity, accurate, sensitive, precise and fast measurements of toxic gases, volatile organic gases, and trace gases have been possible. Therefore, polyurethane membranes have been promising in the development of next-generation gas sensors based on membrane diffusion to ensure real-time and continuous monitoring of gases in industry and academic studies. This study aims to evaluate, compare and discuss the recent developments in the use of polyurethane membranes in existing gas detection technologies with chemical, electrical and optical measurement methods. In these measurement methods, polyurethane structures act as a selectively permeable membrane, an ideal matrix material for conductive additives or a suitable film structure for coating the conductive polymeric films. Conductive additives or conductive film structures for gas sensors play an important role in the detection of the gas structure with the change in electrical properties during the passage of gas molecules. This review has focused on important properties such as selectivity, detection time and measurement sensitivity concerning gas detection technology containing polyurethane, which has been used so far.Öğe Titanium dioxide-multiwalled carbon nanotube/polyimide composite film modified electrodes for simultaneous voltammetric detection of ascorbic acid, uric acid and dopamine as biomarker molecules(Springer, 2022) Gungor, Oznur; Ozgul, Onur; Aksoy, Busra; Okusluk, Funda; Koytepe, SuleymanTitanium dioxide-multiwalled carbon nanotube/polyimide (TiO2-MWCNT/PI) composite film modified electrodes for simultaneous detection of dopamine (DA), uric acid (UA), and ascorbic acid (AA) in clinical or biomedical applications were prepared. Firstly, TiO2-MWCNT and polyimide structures were synthesized. Then, TiO2-MWCNT/PI composites containing different ratios of MWCNT were subsequently prepared and characterized with chemical, thermal and morphological analysis techniques. Synthesized TiO2-MWCNT/PI composites were coated on the platinum electrode surface. Prepared electrodes were used to sense DA, UA, and AA with voltammetric measurements. LOD and LOQ parameters of modified electrodes for DA were observed 8.5114 mu M and 25.5342 mu M, respectively. The R-2 value for the DA in the linear range from 175 to 325 mu M was obtained 0.9967 (in the existence of AA and UA). After five repeatability results, 96.3% AA, 98.2% DA, and 88.3% UA peak currents were maintained. The modified electrode exhibited good selectivity, acceptable durability, high repeatability, and sensitivity.
