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    DERMAL KOZMETİK OLARAK YAYGIN KULLANILAN FONDÖTENLERİN YAPISAL ÖZELLİKLERİNİN Pb Cd VE Cu İÇERİKLERİNİN BELİRLENMESİ
    (2018) Titretir Duran, Serap
    Bu çalışma kapsamında piyasada mevcut fondöten yapılarının Pb, Cd ve Cu içeriklerinin belirlenmesi için sistematik bir yöntem geliştirilmiştir. Fondöten kremlerin içeriği ve menşei çok büyük farklılıklar gösterdiği için farklı markalardan olmak üzere yedi fondöten krem kullanılmıştır. Bu numunelerin yapısal ve içerik analizlerinde fourier dönüşümlü infrared spektrofotometri (FTIR), taramalı elektron mikroskopu(SEM), Enerji Dağılımlı X-Işını (EDX) analizleri kullanılırken, Pb, Cd ve Cu miktarın belirlemek için atomik absorpsiyon spektrometri (AAS) teknikleri kullanılmıştır.EDX, elementel haritalama analizleri krem halinde; metal tayinleri ise hafif asidik (pH=4-5) ortamda 8 saat karıştırılıp süzüldükten sonra çözeltide AAS ile gerçekleştirilmiştir. Sonuç olarak tüm numunelerde yaklaşık olarak 300 ppm Cu, ve 10 ppm Cd varlığı tespit edilmiş; Pb’un ise 1 nolu numune hariç, AAS tayin sınırının altında kaldığı gözlemlenmiştir.
  • Küçük Resim
    Öğe
    Dermal kozmetik olarak yaygın kullanılan fondötenlerin yapısal özelliklerinin Pb Cd ve Cu içeriklerinin belirlenmesi
    (2018) Titretir Duran, Serap
    Bu çalışma kapsamında piyasada mevcut fondöten yapılarının Pb, Cd ve Cu içeriklerinin belirlenmesi için sistematik bir yöntem geliştirilmiştir. Fondöten kremlerin içeriği ve menşei çok büyük farklılıklar gösterdiği için farklı markalardan olmak üzere yedi fondöten krem kullanılmıştır. Bu numunelerin yapısal ve içerik analizlerinde fourier dönüşümlü infrared spektrofotometri (FTIR), taramalı elektron mikroskopu(SEM), Enerji Dağılımlı X-Işını (EDX) analizleri kullanılırken, Pb, Cd ve Cu miktarın belirlemek için atomik absorpsiyon spektrometri (AAS) teknikleri kullanılmıştır.EDX, elementel haritalama analizleri krem halinde; metal tayinleri ise hafif asidik (pH=4-5) ortamda 8 saat karıştırılıp süzüldükten sonra çözeltide AAS ile gerçekleştirilmiştir. Sonuç olarak tüm numunelerde yaklaşık olarak 300 ppm Cu, ve 10 ppm Cd varlığı tespit edilmiş; Pb’un ise 1 nolu numune hariç, AAS tayin sınırının altında kaldığı gözlemlenmiştir.
  • Küçük Resim
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    Determination of Bisphenol a with Poly (p-Aminobenzoic Acid) Modified Gold Electrode by Using Differential Pulse Voltammetry
    (2019) Titretir Duran, Serap
    Abstract: Bisphenol A (BPA) is important matter in chemical industry used in the produce of some food contact materials such as plastics, adhesives and coatings. But BPA has also some toxic effects for human endocrine system and environment. Therefore, novel sensitive and selective methods for determination the level of BPA in environmental, medical samples and foods new measurement methods need to be developed. A novel, sensitive, simple and cheap electrochemical sensor based on poly (p-aminobenzoic acid) p(p-ABA) modified gold electrode (AuE) was developed for the measurement of BPA in water samples. Firstly, AuEs were modified with polymerization of the p-amino benzoic acid as a monomer by using bulk electrolysis in 0.01 M HCl at -250 mV. Then the electrochemical oxidation of BPA carried out in 0.1 M phosphate buffer solution (PBS) pH=6 on p(p-ABA) modified AuE. The effects of various electrochemical parameters, such as scan rate, electroyte type and electrolyte pH were examined. Differential pulse voltammetry (DPV) was used as an ideal analytical method for the qualitative and quantitative detect of BPA in water samples. The developed electrochemical sensor has linear signal to BPA in the range of 2–100 ?M. Prepared electrode was showed the limit of detection (LOD) of 0.26 µM and R2 of 0.999. Additionally, the developed sensor s used to determination the BPA in bottled drinking water sold in Turkish markets by using DPV, and obtains satisfactory results. The recovery values of the bottle water samples in the freezer, at room temperature and in the car were calculated as 102.22%, 104.68% and 106.06% respectively.
  • Küçük Resim Yok
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    Determination of gentamicin by using square wave anodic stripping voltammetry with poly (?-cyclodextrin-p-toluene sulfonic acid) modified glassy carbon electrode
    (Springer, 2024) Burc, Muammer; Titretir Duran, Serap; Gungor, Oznur; Karagozler, Ali Ersin
    In this study, an effective electrochemical method based on modified glassy carbon electrode was developed for the determination of gentamicin. Firstly, the poly beta-cyclodextrin-p-toluene sulfonic acid/glassy carbon electrode as gentamicin selective electrode was prepared by electropolymerization technique. In situ electropolymerization of beta-cyclodextrin and p-toluene sulfonic acid was conducted on bare glassy carbon electrode by controlled potential cycling. Characterization of the prepared poly beta-cyclodextrin-p-toluene sulfonic acid/glassy carbon electrode was performed using cyclic voltammetry and electrochemical impedance spectroscopy. Then, the effects of various parameters were investigated using square wave anodic stripping voltammetry in citrate buffer containing 4.0 mmol L-1 gentamicin. The calibration graph plotted over the range of 0.06-4.0 mmol L-1 gentamicin concentration showed high linearity. Correlation coefficient, detection limit and quantitation limit were obtained from the calibration graph as 0.9999, 3.7 mu mol L-1 and 12.4 mu mol L-1, respectively. According to these results, it is seen that the prepared poly beta-cyclodextrin-p-toluene sulfonic acid/glassy carbon electrode can be successfully used for the determination of gentamicin in many pharmacological, medical and biochemical applications.
  • Küçük Resim Yok
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    Development of Gum-Arabic-based polyurethane membrane-modified electrodes as voltammetric sensor for the detection of phenylalanine
    (Springer, 2021) Alisik, Funda; Burc, Muammer; Titretir Duran, Serap; Gungor, Oznur; Cengiz, Mahmut Alper; Koytepe, Suleyman
    In this study, L-phenylalanine (L-Phe) sensors were prepared from Gum-Arabic-based polyurethanes, by the modification of Pt electrode. Firstly, Gum-Arabic-based polyurethanes were synthesized by solution polymerization technique and characterized with Fourier transform infrared spectroscopy, thermogravimetric analysis, differential thermal analysis, scanning electron microscopy and atomic force microscopy techniques. Then, L-Phe selective electrodes were prepared by coating the platinum electrode with different thickness Gum-Arabic-based polyurethane. L-Phe responses of the modified electrodes were investigated by differential pulse voltammetry technique. Sensor parameters such as scanning speed, film thickness, electrolyte type and pH were examined in detailed. Prepared electrodes were showed R-2 = 0.9972 for the concentration range of 200-1000 mu M L-Phe. The limit of detection and the limit of quantification of the prepared L-Phe selective modified electrode were calculated as 48.01 mu M and as 144.02 mu M, respectively. After ten consecutive measurements with the prepared L-Phe selective electrode, 98.8% stable result was obtained between the first and tenth reading and the RSD% value was found to be 1.21% for ten replicates. Consequently, prepared Gum-Arabic-modified sensors can be used successfully for the detection of the L-Phe with large concentration areas, high sensitivity and repeatability. [GRAPHICS] .
  • Küçük Resim Yok
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    Voltammetric determination of florfenicol by using poly(3-methylthiophene) modified glassy carbon electrode
    (Springer, 2021) Taskin, Imren; Gungor, Oznur; Titretir Duran, Serap
    In this study, poly(3-methylthiophene) modified electrode as a voltammetric sensor was developed for the detection of florfenicol (FF). Firstly, for the modification of glassy carbon electrode (GCE), 3-methylthiophene (3-MTF) was polymerized in acetonitrile (AcN) containing tetrabutylammonium tetrafluoroborate (TBATFB) by cyclic voltammetry (CV) method. Then, in order to determine the florfenicol sensor property of 3-MTF modified GCE, parameters such as electrolyte type and electrolyte pH, scan rate, film thickness, pulse amplitude, and pulse width were investigated by using differential pulse voltammetry method (DPV). When the florfenicol responses of the modified electrode were compared to the unmodified GCE responses, it was found that the florfenicol selectivity, sensitivity, and response stability of the modified electrode were significantly increased. A linear calibration plot was obtained for florfenicol in the concentration range of 0.1-1.0 mM. From the linear calibration curve, the correlation coefficient (R-2 value), determination limit (LOD), and quantitation limit (LOQ) were calculated as 0.999, 0.0399 mM, and 0.1197 mM, respectively. In addition, analytical application of the developed sensor for the determination of florfenicol was carried out in red and chicken meat samples. The recovery efficiency for red and chicken meat samples was obtained from 90.07 to 111.92% by using 3-MTF modified GCE. As a result, an electrochemical sensor was developed for the florfenicol detection which is fast, simple, low cost, 98.72% reproducible, stable, sensitive, and selective.