Person: ÇUBUK, SONER
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ÇUBUK
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Publication Open Access A novel polymeric fluorescence sensor based on acrylated citric acid for detection of melamine adulteration: Application in milk powder(2022-06-18) KÖK YETİMOĞLU, ECE; KAHRAMAN, MEMET VEZİR; ÇUBUK, SONER; Taşci N., Çubuk S., Yetimoğlu E. K., Kahraman M. V.Melamine selective acrylate citric acid (ACA) based polymeric membrane sensor was prepared by radical polymerization method and the sensor was characterized. The sensor showed a selective fluorescent response to melamine (λex/λem=388/425 nm). The sensor response is linear in the concentration range of 3.96x10-9 to 7.93x10-8 mol L-1, the optimum pH value is 6.0 and response time is less than 1 minute. Limit of detection (LOD) and limit of quantification (LOQ) were calculated as 2.32 x 10-10 mol L-1 and as 7.74 x 10-10 mol L-1, respectively. The sensor showed great selectivity towards melamine in the presence of a large number of molecules and ions. The performance of sensor was also confirmed by determining of melamine in milk powder sample and the results were compared with HPLC results and acceptable results were obtained. As a conclusion, the results revealed that the proposed sensor is an interesting alternative for melamine determination. Keywords: Adulteration; Fluorimetric sensor; Melamine; Milk powder; Polymeric sensor.Publication Metadata only Stimuli-responsive smart nanoparticles with well-defined random and triblock terpolymers for controlled release of an anticancer drug(ELSEVIER, 2021) OKTAY, BURCU; Kocal, Gamze; Oktay, Burcu; Eroglu, Gunes Ozen; Kuruca, Serap Erdem; Cubuk, Soner; Apohan, Nilhan KayamanStimuli-responsive nanoplatforms have shown great potential especially in efficient drug release systems. The rate of the anticancer drug release, adverse side effects, and toxicity can be controlled by designing nanoplatforms. Herein, mesoporous hydroxyapatite (HAp) nanoparticles were prepared. Fluorescent and pH-responsive biocompatible well-defined polymer chains were covalently attached by one step and sequential surface-initiated ATRP. The diameter of HAp increased from 120 to 147 and 158 nm with copolymerization. Polyethyleneglycol, poly(dimethylamino)propyl methacrylamide), and poly(fluorescent methacrylate) chains enhanced stimuli responsiveness of drug delivery. The drug release of the DOX@HAp/terpolymer nanoparticles was low under physiological conditions (pH 7.4). However, the release rate of DOX increased when pH was decreased to 5.5. The results of cytotoxicity indicated that the DOX-loaded HAp/terpolymer nanoparticles exhibited high biocompatibility and also caused apoptosis of cancer cells.Publication Metadata only Nutrient dynamics and eutrophication in the Sea of Marmara: Data from recent oceanographic research(ELSEVIER SCIENCE BV, 2017) YALÇIN, BAHATTİN; Yalcin, Bahattin; Artuz, M. Levent; Pavlidou, Alexandra; Cubuk, Soner; Dassenakis, ManosThis work was implemented to study the physicochemical and biological characteristics of the Sea of Marmara and the Turkish straits (TSS: Bosporus and Dardanelles straits) for the period 2010-2013 and to calculate winter and summer fluxes of nutrients (nitrates, phosphates) between the Aegean and Black Seas through the TSS. The brackish Black Sea waters reach the Dardanelles Strait with modified biochemical properties. The salinity and phosphates of the surface waters increased westwards. Biologically labile nutrients of Black Sea origin are utilized through biological processes in the Marmara Sea. On the other hand, increase of nutrients due to land based sources has led to eutrophication problems in the area. The sub surface water layer of Mediterranean origin is oxygen depleted (saturation < 30%) and rich in nutrients. Higher oxygen values indicated water mixing of the Sea of Marmara during winter 2012. Ammonium was the predominant form of inorganic nitrogen. The study area has been classified from Moderate to Bad trophic status. Izmit Bay also faced serious eutrophication problems together with hypoxic conditions below the halocline. Nutrient fluxes through the TSS showed temporal variation in the upper and lower layers related to changes in both nutrient concentrations and the water mass volume fluxes. Surface nitrates and phosphates outflux from the Sea of Marmara to the Aegean Sea was higher than the influx from the Black Sea through Bosporus strait, indicating high enrichment of nutrients in the Sea of Marmara from anthropogenic sources. (C) 2017 Elsevier B.V. All rights reserved.Publication Open Access İndoksakarb Kalıntısı ve Bozunma Ürünü İçin Yeni Bir Tayin Yöntemi Geliştirilmesi(2018-06-30) ÇUBUK, SONER; SONER ÇUBUK;ADNAN AYDINGünümüzde özellikle son 20 yıl süresince kullanımı çarpıcı bir şekilde artan pestisitler, modern tarımda böcekler, yabani otlar, mikroorganizmalar gibi zararlıları kontrol altına almak ve ürün verimini arttırmak için kullanılmakta olup hedef olmayan su, toprak ve gıdaları kirletmelerinin yanı sıra insan, evcil hayvanlar, bal arıları ve kuşlar için potansiyel sağlık riski gösterebilmektedirler. Zehirli olmalarının yanı sıra aynı zamanda bu bileşikler kanser yapıcı oluşumlara da sebep olurlar. Böceklerin ve yabani otların bu kimyasallara olan dayanıklılığının artması sonucu dünya çapında pestisit kalıntı problemlerine yol açan daha fazla pestisit geliştirilmiş ve daha yüksek dozlarda kullanılmaya başlanmıştır. Bununla birlikte pestisitler, besin zincirine çeşitli yollarla girerek canlıların vücutlarında biyolojik birikime uğramakta ve bu besin zincirinde ilerlerken her aşamada daha büyük miktarlara erişmektedirler. Balın da arasında bulunduğu gıdalar başta olmak üzere birçok matristeki pestisitlerin analizinin yapılması canlıların ona ne oranda maruz kaldığının doğru bir şekilde değerlendirilmesi bakımından büyük bir önem arz etmektedir. Bu nedenle pestisitlere ait kalıntı seviyelerinin tespiti ve kullanılan metotların güncel mevzuatlarda yer alan tolere edilebilir kalıntı konsantrasyonları da kapsaması beklenmektedir. Son yıllarda bu alanda bazı çalışmalar yapılmış olmasına rağmen ülkemizde ballardaki pestisit tayinleriyle ilgili çok az çalışma bulunmaktadır. Çalışmamızda bal örneklerinde İndoksakarb ((S)-7-kloro-3-[meteksikarbonil-(4-trifluorometoksi-fenil)-karbamoil]-2,5-dihidro-indeno[1,2-e][1,3,4]oksadiazin-4a(3H)-karboksilik asit metil esteri) kalıntısının ve bozunma ürününün belirlenmesi için yeni bir yöntem geliştirilmiştir. Diklorometan ile ekstraksiyon sonrasında, Gaz kromatograf-kütle Spektrometresi kullanılarak indoksakarb ve bozunma ürününü tayin edilmiştir. Geliştirilen metota ait geri kazanım yüzdesi, tespit ve tayin sınırları sırasıyla %78,7±5,5 ; 0,03 mg/kg ve 0,11 mg/ kg olarak hesaplanmıştır. İndoksakarb ile kirletilmiş kestane, çiçek, çam ve ayçiçek balı numuneleri 3 farklı sıcaklıkta 8 ay süresince izlenmiş ve beşinci ayda 4-(trifluorometoksi)fenil izosiyanat, literatürde belirtilenlerden farklı bir bozunma ürünü olarak tespit edilmiştir.Publication Metadata only Development of stability indicating a HPLC method for nilotinib for the determination and validation of process- related and degradation Impurities(2022-11-20) ÇUBUK, SONER; Ceyhan Daş P., Çubuk S.Publication Metadata only Development of photopolymerized fluorescence sensor for glucose analysis(ELSEVIER SCIENCE SA, 2013) KÖK YETİMOĞLU, ECE; Cubuk, Soner; Yetimoglu, Ece Kok; Kahraman, M. Vezir; Demirbilek, Pinar; Firlak, MelikeThe sensing membrane was prepared by photopolymerization of 4-vinylphenylboronicacid (VPBA), hydroxyethylmethacrylate (HEMA) and poly(ethylene glycol) diacrylate (PEG-DA). The membran is capable of determining glucose between 2.78 x 10(-4) mM and 5.56 x 10(-3) mM with a limit of detection of 0.89 x 10(-5) mM, and limit of quantification 3.17 x 10(-3) mM (n = 7). It can be completely regenerated by using distilled water. The sensor performance characteristics such as response time, dynamic working range and sensitivity were reported. The proposed sensor was then applied successfully for the determination of glucose in blood samples. The optical sensor was stable, cost effective, easy to prepare, rapid and simple for the determination of glucose. (C) 2013 Elsevier B.V. All rights reserved.Publication Metadata only Reusable fluorescent photocrosslinked polymeric sensor for determining lead ions in aqueous media(PERGAMON-ELSEVIER SCIENCE LTD, 2016) KÖK YETİMOĞLU, ECE; Cubuk, Soner; Tasci, Nese; Kahraman, Memet Vezir; Bayramoglu, Allay; Yetimoglu, Ece KokIn this study, l-vinylimidazole units bearing photocured films were prepared as fluorescent sensors towards Pb2+ in aqueous solutions. The influence of experimental parameters such as pH, time and foreign ion concentrations were investigated. Sensor response was linear over a concentration range of 4.83 x 10(-8) to 4.83 x 10(-7) mol L-1. The sensor was highly sensitive with a detection limit as low as 1.87 x 10(-8) mol L-1, and having a selectivity of over four thousand fold. The response time of the sensor was found to be 5 min. When stored in a desiccator at room temperature the sensor showed good stability after a 5 month period. The fluorescence sensors were successful in the determination of Pb2+ in water samples as well as in the determination of the quantitative amount of lead and the results were satisfying. Compared with previously reported literature, the prepared new sensor is highly sensitive and selective. (C) 2016 Elsevier B.V. All rights reserved.Publication Metadata only Recovery of Au(III) ions by Au(III)-imprinted hydrogel(SPRINGER INTERNATIONAL PUBLISHING AG, 2016) KÖK YETİMOĞLU, ECE; Firlak, Melike; Cubuk, Soner; Yetimoglu, Ece Kok; Kahraman, Memet V.A new Au(III)-imprinted hydrogel (Au(III)-Imp) was prepared by the photopolymerisation of 4-acryloylmorpholine (AcM), 2-hydroxyethyl acrylate (HEA), and poly(ethylene glycol) diacrylate (cross-linking monomer, PEG-DA) in the presence of gold ions. In addition, non-imprinted hydrogel (N-Imp) was similarly prepared without Au(III) ions The Au(III)-Imp hydrogel was characterised by several techniques. To achieve the optimal conditions, effect of pH, time, and initial metal ion concentrations were investigated using a batch system. The pre-concentration factor for Au(III) ions was found to be at least 100. The analytical parameters of the method were determined and the method was also successfully applied to computer circuit board scrap samples. The reusability of the Au(III)-Imp hydrogel was also determined. (C) 2016 Institute of Chemistry, Slovak Academy of SciencesPublication Metadata only Cu(II) iyonu tayini için çevre dostu yeni bir yöntem geliştirilmesi(2021-10-07) ÇUBUK, SONER; Koçoğlu N., Çubuk S.Çalışmamızda Cu(II) iyonu tayini için polimerik esaslı yüksek seçiciliğe sahip çevre dostu yeni bir spektrofluorimetrik yöntem geliştirilmiştir. Bu amaçla hazırlanan polimerik membranın karakterizasyonunun ardından Cu(II) iyonu tayini için dalgaboyu, pH, süre ve yabancı iyon etkisini de içeren en uygun şartlar belirlenmiştir. Ayrıca geliştirdiğimiz yöntemde kullanılan polimerik sensöre ait kararlılık, sensör ömrü ve tekrarlanabilirlik koşulları tespit edilmiş ve geri kazanım çalışmaları gerçekleştirilmiştir. Gerçek örnekler üzerine uygulanabilirliği için sertifikalı referans atık su numuneleri kullanılmıştır. Yöntemimiz ile 20 saniye kadar kısa bir süre içerisinde yüksek sPublication Metadata only Synthesis and photoluminescence of LiCaBO3: M (M: Pb2+ and Bi3+) phosphor(ELSEVIER, 2012) BAŞAK, ALİ SADİ; Pekgozlu, Ilhan; Erdogmus, Ertugrul; Cubuk, Soner; Basak, Ali SadiPure, Pb2+ and Bi3+ doped LiCaBO3 materials were prepared by a solution combustion synthesis method. The phase of LiCaBO3 were determined using the powder XRD and FTIR. The photoluminescent properties of Pb2+ and Bi3+ doped LiCaBO3 materials were investigated using spectrofluorometer at room temperature. The emission bands of LiCaBO3: Pb2+ and LiCaBO3: Bi3+ were observed at 296 and 378 nm, respectively. LiCaBO3 with different Pb2+ and Bi3+ doping concentrations were analyzed at room temperature. The Stokes shifts of LiCaBO3: Pb2+ and LiCaBO3: Bi3+ were calculated to be 3952 and 6440 cm(-1), respectively. (C) 2012 Elsevier B.V. All rights reserved.