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Öğe Bazı iletken polimer elektrotlar ile yeni elektrokimyasal sensörlerin hazırlanması ve ilaç etken maddelerine uygulanması(İnönü Üniversitesi, 2016) Kuyumcu Savan, EbruBu çalışmada, poli (3-metiltiyofen), polipirol ve polianilin ile karbon nano tüp parçacıkları kullanmak suretiyle, camsı karbon elektrot yüzeyinde elektropolimerik karbon nano tüp elektrotlar hazırlanmıştır. Hazırlanan karbon nano tüp modifiye camsı karbon, poli (3-metiltiyofen), polipirol ve polianilin kompozit elektrotların levodopa, karbidopa ve benserazide karşı elektrokatalitik etkisi incelenmiştir. Daha sonra, elektropolimerik karbon nano tüp elektrotların sensör karakteristiklerini etkileyen parametreler (polimerik film kalınlığı, karbon nano tüp derişimi, karbon nano tüp parçacıklarının film kalınlığı, destek elektrolit tür ve pH'sı) sistematik olarak optimize edilmiştir. Önerilen yöntemler geniş bir şekilde valide edilmiş, bu maddelerin birbirleri varlığında ve farmasötik dozaj formlarında tayinine başarılı bir şekilde uygulanmıştır. Elde edilen sonuçlar, modifiye elektrotların askorbik asit varlığında bu ilaçların tayinine uygulanabileceğini göstermiştir.Öğe Electrochemical Detection of Epinephrine in The Presence of Ascorbic Acid at Poly (p-Aminobenzene Sulfonic Acid) Modified Sensor(2018) Erdoğdu, Gamze; Kuyumcu Savan, Ebru; Yağcı, Şevket Zişan B.Abstract: In this study, a rapid, reliable, selective and sensitive simultaneous voltammetric determination of Epinephrine (EP) in the presence of ascorbic acid at poly (p-aminobenzene sulphonic acid, ABSA) modified sensor was aimed. The glassy carbon electrode was successfully modified with ABSA in 0.1 M KCl solution by the cycling voltammetry technique. The sensor, modified with a polymeric thin film, showed excellent electrocatalytic activity against the oxidation of EP and ascorbic acid (AA). The results showed that the oxidation potential and current responses of EP and AA improved significantly. The modified sensor showed excellent response with limit of detection as 50 nM in the determination of EP at the 5.0 - 53.2 ?M concentration range under optimum conditions. In real sample analyzes performed in pharmaceutical preparation and blood serum, recovery values were 77.3%-98.4%. The results obtained show that the modified sensor can be applied to the detection of EP in the presence of AA. The proposed sensor is promising for routine analysis because of its high selectivity, reproducibility, reproducibility and long-term stability characteristics and high recovery values obtained in pharmaceutical and biological samples.Öğe Investigation of the Voltammetric Behavior of Methyldopa at a Poly (p-Aminobenzene Sulfonic Acid) Modified Sensor(2019) Erdoğdu, Gamze; Yağcı, Şevket Zişan; Kuyumcu Savan, EbruAbstract: Objectives: The aim was to modify carbon electrodes with (p-aminobenzene sulfonic acid) and use them as a sensor for sensitive and reliable detection of methyldopa (MD) and ascorbic acid. Materials and Methods: Electropolymerization was performed by cyclic voltammetry in 0.1 M KCl solution. The modified sensor has a high electrocatalytic effect for oxidation of MD, which appeared in the pH range of 2-11 by differential pulse voltammetry (DPV) techniques. Results: For the voltammetric determination of MD, the best results were acquired by DPV in phosphate buffer solution (PBS) (pH 3). The calibration plot of the proposed sensor is linear in two concentration ranges of 1.0-30 and 30.0-300.0 ?M. The calibration equations over these ranges are I pa (?A)=1.21×C (?M)+30.81, R2 =0.994 and I pa (?A)=0.53×C (?M)+53.30, R2 =0.9975, respectively. In the sensitivity studies, the limit of quantification and the limit of detection were 10.6 nM and 5.0 nM, respectively. The modified sensor was used for the simultaneous determination of interfering substances such as MD and ascorbic acid in real samples. Conclusion: The obtained results revealed that the prepared modified electrode and the proposed method have good sensitivity, repeatability, reproducibility, and stability.Öğe PİROL VE ÇOK DUVARLI KARBON NANOTÜP MODİFİYE SENSÖR İLE LEVODOPA VE BENSERAZİD’İN ELEKTROKİMYASAL OLARAK EŞZAMANLI TAYİNİ(2020) Kuyumcu Savan, Ebru; Erdoğdu, GamzeBu çalışmada, susuz ortamda camsı karbon elektrot (CKE) üzerinde pirolün elektropolimerizasyonu ve çok duvarlı karbon nanotüpün (ÇDKN) modifikasyonu ile elektrokimyasal bir sensör geliştirilmiştir. Polipirol ve ÇDKN temelli elektrot, Parkinson hastalığı tedavisinde kullanılan etken maddeler olan Levodopa ve Benserazid’in elektrokimyasal olarak kantitatif tayini için kullanılmıştır. Modifiye edilmiş sensör üzerindeki farklı parametrelerin etkisi test edilmiş ve optimize edilen yöntem yüksek seçicilik ve hassasiyet göstermiştir. Modifiye sensör, 10 - 50 µM Levodopa ve 100 - 500 µM Benserazid derişim aralıklarında doğrusal yanıtlar vermiştir. Levodopa ve Benserazid için sırasıyla 3.65 µM ve 1.99 µM'lık tayin sınırları elde edilmiştir. Sensörün aktivitesi, girişim yapan türlerden biri olan askorbik asit varlığında başarıyla test edildi. Geliştirilen yöntem, gerçek idrar numunelerinde ve farmasötik dozaj formundaki Levodopa ve Benserazid’in tayininde başarıyla uygulanmıştır.Öğe PİROL VE ÇOK DUVARLI KARBON NANOTÜP MODİFİYE SENSÖR İLE LEVODOPA VE BENSERAZİD’İN ELEKTROKİMYASAL OLARAK EŞZAMANLI TAYİNİ(2020) Kuyumcu Savan, Ebru; Erdoğdu, GamzeÖz: Bu çalışmada, susuz ortamda camsı karbon elektrot (CKE) üzerinde pirolün elektropolimerizasyonu ve çok duvarlı karbon nanotüpün (ÇDKN) modifikasyonu ile elektrokimyasal bir sensör geliştirilmiştir. Polipirol ve ÇDKN temelli elektrot, Parkinson hastalığı tedavisinde kullanılan etken maddeler olan Levodopa ve Benserazid’in elektrokimyasal olarak kantitatif tayini için kullanılmıştır. Modifiye edilmiş sensör üzerindeki farklı parametrelerin etkisi test edilmiş ve optimize edilen yöntem yüksek seçicilik ve hassasiyet göstermiştir. Modifiye sensör, 10 - 50 µM Levodopa ve 100 - 500 µM Benserazid derişim aralıklarında doğrusal yanıtlar vermiştir. Levodopa ve Benserazid için sırasıyla 3.65 µM ve 1.99 µM'lık tayin sınırları elde edilmiştir. Sensörün aktivitesi, girişim yapan türlerden biri olan askorbik asit varlığında başarıyla test edildi. Geliştirilen yöntem, gerçek idrar numunelerinde ve farmasötik dozaj formundaki Levodopa ve Benserazid’in tayininde başarıyla uygulanmıştır.Öğe Poly(3-methylthiophene) modified gold sensor for determination of 3,4-dihydroxyphenylacetic acid, ascorbic acid and uric acid in biological fluids using voltammetric techniques(2019) Kuyumcu Savan, Ebru; Erdoğdu, GamzeAbstract: Electrochemical polymerization was carried out in a one-compartment cell containing deaerated acetonitrile, and 100 mM tetrabutylammonium tetrafluoroborate monomer of 3-methylthiophene. The polymer films were grown on a gold electrode by bulk electrolysis at 1.700 V (vs. Ag/Ag+). The modified sensor showed an excellent electrocatalytic effect towards oxidation of the mixture of 3,4-dihydroxyphenylacetic acid (DOPAC), ascorbic acid and uric acid, which appeared at a pH range of 2-11 by differential pulse voltammetry (DPV ) techniques. The best results for determination of DOPAC were obtained by DPV in PBS (pH 7.00). A calibration curve was obtained in the DOPAC concentration range of 1.0-50.0 ?M (r = 0.9948). Limit of detection and limit of quantification were found as 0.066 ?M and 0.220 ?M, respectively. The results of the experiments indicated that the sensor has good stability, sensitivity and reproducibility for at least one month if stored in dry air.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 Simultaneous determination of levodopa and benserazide using poly(3-methylthiophene) and a multi-walled carbon nanotube sensor(Springer, 2017) Kuyumcu Savan, Ebru; Erdoadu, GamzeRapid, reliable, reproducible, and repeatable modified sensor designs have been developed to distinguish the binary mixture of levodopa and benserazide in the presence of ascorbic acid using voltammetric techniques. Sixteen designed sensors were prepared by dropwise of different concentrations and quantities of multi-walled carbon nanotube (MWCNT) dispersions to bare glassy carbon electrode (GCE) surface and also the bottom and the top of the poly(3-methylthiophene) films. The best simultaneous determination was accomplished with the sensor dropped 20 mu L of 1.0% MWCNT to GCE. Under optimum conditions, the electrocatalytic oxidation peak currents of levodopa and benserazide showed linear dynamic range, good stability, and sensitivity with detection limit of 10.3 and 32.5 mu mol L-1, respectively. The proposed method has been successfully applied for the determination of levodopa and benserazide in urine samples and pharmaceutical preparations, demonstrating the feasibility and reliability.
