Browsing by Author "Ekmen, Elvan"

Now showing 1 - 3 of 3

Efficient and Selective Separation of Metronidazole From Human Serum by Using Molecularly Imprinted Magnetic Nanoparticles
(Wiley-v C H verlag Gmbh, 2018) Bilici, Mustafa; Zengin, Adem; Ekmen, Elvan; Cetin, Demet; Aktas, Nahit
Magnetic molecularly imprinted nanoparticles were prepared through surface-initiated reversible addition fragmentation chain transfer polymerization by using metronidazole as a template. The molecularly imprinted magnetic nanoparticles were characterized by attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The adsorption characteristics were also investigated and the kinetics of the adsorption of metronidazole on the imprinted nanoparticles were described by the second-order kinetic model with the short equilibrium adsorption time (30min). The adsorption isotherm was well matched with the Langmuir isotherm in which the maximum adsorption capacity was calculated to be 40.1mg/g. Furthermore, the imprinted magnetic nanoparticles showed good selectivity as well as reusability even after six adsorption-desorption cycles. The imprinted magnetic nanoparticles were used as a sorbent for the selective separation of metronidazole from human serum. The recoveries of metronidazole from human serum changed between 97.5 and 99.8% and showed similar sensitivity as an enzyme-linked immunoassay method. Therefore, the molecularly imprinted magnetic nanoparticles might have potential application for the selective and reliable separation of metronidazole from biological fluids in clinical applications.
Preparation of Magbetic Nanoplatforms Basen on Surface Enhanced Raman Spectroscopy for Selective Detection of Malachite Green
(2019) Ekmen, Elvan; Zengin, Adem
ÖZET MALAHİT YEŞİLİ'NİN SEÇİCİ TAYİNİ İÇİN YÜZEYDE ZENGİNLEŞTİRİLMİŞ RAMAN SPEKTROSKOPİSİ TEMELLİ MANYETİK NANOPLATFORMLARIN HAZIRLANMASI EKMEN, Elvan Yüksek Lisans Tezi, Kimya Mühendisliği Anabilim Dalı Tez Danışmanı: Doç. Dr. Adem ZENGİN Mayıs 2019, 63 sayfa Bu çalışmada, boyarmadde olarak kullanılan malahit yeşilinin tayininde kullanılmak üzere moleküler baskılanmış manyetik nanopartiküller hazırlanmıştır. İlk olarak solvotermal yöntemle manyetik nanopartiküller sentezlenmiş, partikül yüzeyi ilk olarak iyodsilan (IPTS) ile modifiye edilmiş, ardından nanopartiküller metakrilik asit (MAA, Monomer), etilen glikol dimetakrilat (EGDMA, çapraz bağlayıcı), azobis isobütironitril (AIBN, başlatıcı), malahit yeşili (MY, kalıp molekül), N-iyodosüksinamid (NIS, katalizör) içerisinde dispers edilmiş ve yüzeyde moleküler baskılama yöntemi ile baskılanmış polimerler tersinir zincir transfer katalizlenmiş polimerleşme (RCTP) ile hazırlanmıştır. Ardından gümüş dendrimer kaplı silisyum yüzeyler ile çeşme suyu içerisinde MY molekül tayini gerçekleştirilmiştir. Baskılanmış nanopartikül yüzeylerde malahit yeşili için maksimum adsorpsiyon kapasitesi ve süresi sırasıyla 34.6 mg/g, 60 dak. olarak belirlenmiş ve partikül yüzeyinde MY'ne karşı baskılama faktörü 3.69 olarak hesaplanmıştır. MY molekülüne yapıca benzer (kristal mavisi ve rosolik asit) ile seçicilik çalışması yapılmış ve nanopartiküllerin MY'ne karşı oldukça seçici olduğu görülmüştür. Çoklu adsorpsiyon-desorpsiyon çevriminden sonra baskılanmış nanopartiküllerin kullanılabilirliğinin ve seçiciliğinin değişmediği görülmüştür. SERS aktif dendrimer yüzeyler ile MY molekülü çeşme suyunda tayin edilebilme alt sınırı (LOD) değeri 0,06 pM olarak belirlenmiştir. Ayrıca SERS aktif yüzeylerde bulunan malahit yeşili UV/O3 kullanılarak 60dak. sonunda tamamen yüzeyden uzaklaştırılarak rejenere edilmiştir. Yüzeylerin UV/O3'ekarşı dayanıklı ve en az 10 defa rejenere edilebilme özelliğinin bulunduğu belirlenmiştir. Anahtar Kelimeler: Malahit yeşili, Nanopartikül, RCTP, SERS
Surface Molecularly-Imprinted Magnetic Nanoparticles Coupled With Sers Sensing Platform for Selective Detection of Malachite Green
(Elsevier Science Sa, 2020) Ekmen, Elvan; Bilici, Mustafa; Turan, Eylem; Tamer, Ugur; Zengin, Adem
Herein, a novel analytical method was reported for sensitive and selective quantification of malachite green (MG) in tap water and carp samples based on a combination of surface-enhanced Raman spectroscopy (SERS) and molecular imprinting technology. For this purpose, surface molecularly-imprinted magnetic nanoparticles (MIP@Fe3O4 NPs) were synthesized through recently developed living/controlled radical polymerization mechanism referred to as reversible chain transfer catalyzed polymerization (RTCP). Surface characterization of MIP@Fe3O4 NPs was carried out in detail by using the combination of several analytical techniques and the results showed the presence of a thin polymer layer on the nanoparticles. Rebinding properties, selectivity and reusability of the nanoparticles were investigated and the obtained results indicated the prepared nanoparticles had excellent selectivity, high adsorption capacity, fast adsorption kinetics and multiple-uses with an imprinting factor of 3.86. Then, silver dendrites (Ag NPs) were deposited on silicon wafers and used as SERS sensing platform. Moreover, surface properties of the SERS substrate were also investigated in detail in terms of stability, reusability and homogeneity. After that, the eluted MG from the imprinted nanoparticles was dropped on the sensing platform and SERS analysis was carried out. Under optimized conditions, limit of detection and limit of quantification were determined to be 1.50 pM and 4.96 pM for tap water, respectively and 1.62 pM and 5.38 pM for carp samples, respectively within acceptable recovery rates and standard deviations. The overall results indicated that the proposed method can be effectively used for the quantification of trace amounts of MG in tap water and carp samples. Moreover, the proposed method is promising for development of new ways to prepare MIPs via surface-initiated RTCP.