Browsing by Author "Osman, Bilgen"
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Item Adsorption and removal of diethyl phthalate from aqueous media with poly(hydroxyethyl methacrylate) nanobeads(Desalination, 2016-04-30) Özer, Elif Tümay; Sarıkaya, Aslı Göçenoğlu; Osman, Bilgen; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; 0000-0002-7161-7003; AAI-3137-2021; AAC-6901-2020; ABF-4791-2020; 37047586000; 56709610700; 15221651200In this study, poly (hydroxyethyl methacrylate) (PHEMA) nanobeads with an average size of 115nm were prepared by emulsion polymerization. The nanobeads were characterized with infrared spectroscopy, scanning electron microscopy, and zeta size analysis. The surface area of the PHEMA nanobeads was calculated as 541.4m(2)/g. Then, diethyl phthalate (DEP) removal efficiency of the PHEMA nanobeads from aqueous media was investigated. At a fixed adsorbent/solution ratio, various factors affecting the adsorption of DEP from aqueous solution such as pH, initial concentration, contact time, temperature, and adsorbent dosage were analyzed. The maximum DEP adsorption capacity of the PHEMA nanobeads was determined as 265.1mg/g at pH 4.0, 25 degrees C. The Sips isotherm model fits the experimental data in the wide range of DEP concentration tested (1-300mg/L). The pseudo-first-order, pseudo-second-order, modified Ritchie's-second-order kinetic models were used to test the adsorption kinetics. The DEP adsorption capacity of the nanobeads did not change after five batch successive usages. DEP removal efficiency of the PHEMA nanobeads from different water media such as saliva, sweat, and tap water was also evaluated. The removal efficiencies in the range from 82.4 to 100.0% demonstrate the usability of PHEMA nanobeads for DEP removal from real samples.Item Adsorption equilibrium, kinetics and thermodynamics of alpha-amylase on poly(DVB-VIM)-Cu+2 magnetic metal-chelate affinity sorbent(Springer, 2012-09) Osman, Bilgen; Kara, Ali; Demirbel, Emel; Kök, Şenay; Beşirli, Necati; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; AAG-6271-2019; ABF-4791-2020; 15221651200; 7102824859; 54681740300; 37054138900; 6507924888Designing an immobilised metal ion affinity process on large-scale demands that a thorough understanding be developed regarding the adsorption behaviour of proteins on metal-loaded gels and the characteristic adsorption parameters to be evaluated. In view of this requirement, interaction of alpha-amylase as a model protein with newly synthesised magnetic-poly(divinylbenzene-1-vinylimidazole) [m-poly(DVB-VIM)] microbeads (average diameter, 53-212 mu m) was investigated. The m-poly(DVB-VIM) microbeads were prepared by copolymerising of divinylbenzene (DVB) with 1-vinylimidazole (VIM). The m-poly(DVB-VIM) microbeads were characterised by N-2 adsorption/desorption isotherms, electron spin resonance, elemental analysis, scanning electron microscope and swelling studies. Cu2+ ions were chelated on the m-poly(DVB-VIM) beads and used in adsorption of alpha-amylase in a batch system. The maximum alpha-amylase adsorption capacity of the m-poly(DVB-VIM)-Cu2+ beads was determined as 10.84 mg/g at pH 6.0, 25 A degrees C. The adsorption data were analyzed using three isotherm models, which are the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The pseudo-first-order, pseudo-second-order, modified Ritchie's-second-order and intraparticle diffusion models were used to test dynamic experimental data. The study of temperature effect was quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes.Publication Adsorption of cinnabarinic acid from culture fluid with magnetic microbeads(Wiley, 2016-02-01) Sarıkaya, Aslı Göçenoğlu; Osman, Bilgen; Kara, Ali; Pazarlıoğlu, Nurdan; Besirli, Necati; GÖÇENOĞLU SARIKAYA, ASLI; OSMAN, BİLGEN; KARA, ALİ; Besirli, Necati; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü,; 0000-0002-7161-7003; 0000-0001-8406-149X; 0000-0003-2457-6314; AAC-6901-2020; ABF-4791-2020; JXW-6168-2024; AAG-6271-2019In this study, antimicrobial pigment cinnabarinic acid (CA) was produced from Pycnoporus cinnabarinus in laboratory-scale batch cultures. Magnetic poly(ethylene glycol dimethacrylate-N-methacryloyl-l-tryptophan methyl ester) [m-poly(EGDMA-MATrp)] beads (average diameter = 53-103 mu m) were synthesized by copolymerizing of N-methacryloyl-l-tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA) in the presence of magnetite (Fe3O4) and used for the adsorption of CA. The m-poly(EGDMA-MATrp) beads were characterized by N-2 adsorption/desorption isotherms (Brunauer Emmet Teller), X-ray photoelecron spectroscopy, scanning electron microscopy, infrared spectroscopy, thermal gravimetric analysis, electron spin resonance and swelling studies. The efficiency of m-poly(EGDMA-MATrp) beads for separation of CA from culture fluid was evaluated. The effects of pH, initial concentration, contact time and temperature on adsorption were analyzed. The maximum CA adsorption capacity of the m-poly(EGDMA-MATrp) beads was 272.9mgg(-1) at pH7.0, 25 degrees C. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. The adsorption process obeyed pseudo-second-order kinetic model. Thermodynamic parameters H = 5.056kJmol(-1), S = 52.44JK(-1)mol(-1) and G = -9.424kJmol-(1) to -11.27kJmol-(1) with the rise in temperature from 4 to 40 degrees C indicated that the adsorption process was endothermic and spontaneous.Publication Adsorptive removal of 4-hydroxybenzoic acid via cross-linked polymeric microbeads: Analysis of isothermal, kinetic and thermodynamic parameters(Taylor & Francis Inc, 2023-05-26) Özer, Elif Tumay; Osman, Bilgen; KÜÇÜK, MELİKE; OSMAN, BİLGEN; TÜMAY ÖZER, ELİF; Bursa Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Bölümü.; 0000-0001-8406-149X; JCP-4547-2023In this study, the performance of cross-linked microbeads prepared through suspension polymerization was investigated for removal of 4-hydroxybenzoic acid (4-HBA) from aqueous solution. Adsorption studies were conducted at different pHs (2.0-8.0), temperatures (282-308 K) and initial 4-HBA concentrations (1-500 mg/L). The maximum 4-HBA adsorption was 49.05 +/- 2.89 mg/g at pH 2.0 (282 K). The adsorption data obeyed to the Langmuir isotherm model. The modified Ritchie second-order and the pseudo second-order kinetic model fitted the adsorption data. The 4-HBA adsorption capacity did not significantly change after 10 consecutive usages. Gibbs free energy changes of the adsorption were calculated as -24.372, -28.431 and -29.093 kJ/mol for 282, 298 and 308 K, respectively. The microbeads were also used for the removal of 4-HBA from spiked river water samples. The removal efficiencies of 43.2% to 68.8% and RSDs of 0.49% to 4.78% demonstrated the usability of the microbeads in application.Item Afinite mikroküreler ile sulu çözeltiden tetrasiklin uzaklaştırılması(Bursa Uludağ Üniversitesi, 2020-03-19) Karalı, Recep; Osman, Bilgen; Bursa Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Gıda Mühendisliği Anabilim Dalı.; 0000-0003-4847-9252Bu çalışmada, poli (etilenglikol dimetakrilat N-metakriloil-amido-L-triptofan metil ester [poli(EGDMA-MATrp)] mikrokürelerin tetrasiklin (TC) adsorpsiyonu için kullanılabilirliği araştırıldı. Poli(EGDMA-MATrp) mikroküreler süspansiyon polimerizasyonu tekniği ile sentezlendi ve FTIR ve SEM analizleri ile karakterize edildi. Sentezlenen mikroküreler sulu çözeltiden TC adsorpsiyonunda kullanıldı. Adsorpsiyon kapasitesine pH, başlangıç TC derişimi, sıcaklık ve temas süresinin etkisi araştırıldı. Maksimum adsorpsiyon kapasitesi 4oC‘de 9,8 mg TC/g olarak belirlendi (pH 5,0). Poli(EGDMA-MATrp) mikrokürelere TC adsorpsiyonunun Freundlich adsorpsiyon izoterm modeline ve yalancı-ikinci derece kinetik model ile partikül içi difüzyon kinetik modeline uygun olduğu belirlendi. TC adsorpsiyonuna ait ΔHo değeri - 7,97 kJ/mol, ΔSo değeri 0,01465 kJ/mol.K olarak hesaplandı. ΔGo (kJ/mol) değerleri ise; 4oC, 10oC ve 25oC sıcaklık için sırasıyla -12,03, -12,12 ve -12,34 kJ/mol olarak belirlendi. Termodinamik parametreler poli(EGDMA-MATrp) mikrokürelere TC adsorpsiyonunun ekzotermik ve istemli olduğunu gösterdi.Item Amoksisilin baskılanmış polimerik nanopartikül gömülü nanolifli yüzeyin hazırlanması ve ilaç salım özelliklerinin araştırılması(Bursa Uludağ Üniversitesi, 2022-06-28) Çerçi, Azize; Osman, Bilgen; Bursa Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Biyomalzemeler Anabilim Dalı.; 0000-0002-3965-8841Bu çalışmada, elektro çekim yöntemi kullanılarak amoksisilin (AMOX) baskılanmış poli (hidroksietil metakrilat-N-metakriloil-amido-L-glutamik asit metil ester) (AMOX-MIP) nanopartikül gömülü polivinil alkol (PVA) /sodyum aljinat (SAlg) nanolifli yüzey (PVA/SAlg/AMOX-MIP) hazırlandı. Nanopartiküller moleküler baskılama metodu kullanılarak sentezlendi ve Fourier Transform infrared spektroskopisi (FTIR), alan emisyonlu taramalı elektron mikroskopisi (FE-SEM), konvansiyonel geçirimli elektron mikroskopisi (CTEM) ve Zeta potansiyel analizi ile karakterize edildi. Moleküler baskılama metodu kalıp molekül, fonksiyonel monomer ve çapraz bağlayıcı oranlarının değiştirilmesi ile optimize edildi. PVA/SAlg/AMOX-MIP nanolifli yüzey, PVA/SAlg elektro çekim çözeltisine %15 (w/v) oranında AMOX-MIP nanopartikül eklenmesi ile hazırlandı. Nanolifli yüzey glutaraldehit (GA) ile çapraz bağlandı ve FTIR, SEM, temas açısı ölçümü, şişme, degredasyon ve kalınlık testleri ile karakterize edildi. AMOX-MIP ve baskılanmamış (NIP) nanopartiküller ile PVA/SAlg/AMOX-MIP nanolifli yüzeyden ilaç salım çalışmaları yapıldı. İlaç salım kinetiği sıfırıncı derece, birinci derece, Higuchi ve Korsmeyer-Peppas modelleri kullanılarak araştırıldı. AMOX-MIP nanopartiküller 50 nm çapında olup -36,4 mV Zeta potansiyel değerine sahiptir. Çapraz bağlı PVA/SAlg/AMOX-MIP nanolifli yüzeyin ortalama lif çapı 304,5±92,9 nm, kalınlığı 0,658±0,01 mm, şişme oranı %333 ve temas açısı 52°±1,02’dir. 20 gün sonunda degredasyon oranı %7,8’dir. AMOX-MIP ve NIP nanopartiküllerden ilaç salımı ilk 30 dakikada sırasıyla %76,8 ve %93,8’dir ve 4 saat süre sonunda %85,7 ve %97,6 değerine ulaşmaktadır. PVA/SAlg/AMOX-MIP nanolifli yüzeyden AMOX salımı ise ilk 30 dakikada %48, 4 saatte %77,3 ve 4 gün sonunda %100’dür. İlaç salımı Korsmeyer-Peppas modeline uygundur. Elde edilen sonuçlara göre, PVA/SAlg/AMOXMIP nanolifli yüzey antibiyotik salımı yapan yara örtüsü uygulamalarında yüksek bir kullanım potansiyeline sahiptir.Item Application of affinity microspheres for effective SPE cleanup before the determination of sulfamerazine by HPLC(Elsevier, 2018-04-19) Kılıç, Gözde; Tüzmen, Nalan; Osman, Bilgen; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; ABF-4791-2020; 15221651200This paper describes the application of poly (ethylene glycol dimethacrylate-N-methacryloyl-L-tryptophane methyl ester) [p(EGDMA-MATrp)] microspheres as an affinity sorbent for the SPE (solid phase extraction) cleanup of sulfamerazine (SMR) from food samples of animal origin before high performance liquid chromatography (HPLC) analysis. The microspheres were prepared by suspension polymerization of ethylene glycol dimethacrylate (EGDMA) and N-methacryloyl-L-tryptophane methyl ester (MATrp) as a crosslinker and a monomer, respectively. Various parameters affecting the SPE cleanup efficiency of the p(EGDMA-MATrp) microspheres (contact time, pH, initial SMR concentration, ionic strength etc.) were optimized. Under the optimized conditions, maximum adsorption capacity was found to be 8.55 +/- 0.44 mg/g sorbent at pH 5.0. 90% of the adsorbed SMR was desorbed by using ACN:MeOH (5:5) mixture as a desorption agent. Applicability of the microspheres for the SPE cleanup of SMR residues in the food samples such as egg and milk with HPLC was also determined. It was demonstrated that the prepared p(EGDMA-MATrp) microspheres could be repeatedly applied for SPE cleanup of sulfamerazine before chromatographic analysis. Also, the recoveries of SMR in milk and egg samples were reasonably satisfactory and in the range of 71 to 90%.Item Assesment of dimethyl phthalate removal from aqueous phase using barium hexaferrite containing magnetic beads(Academic Press Inc Elsevier Science, 2012-07-15) Osman, Bilgen; Özer, Elif Tümay; Kara, Ali; Güçer, Şeref; Beşirli, Necati; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; 0000-0003-0610-2019; AAI-3137-2021; ABF-4791-2020; 15221651200; 37047586000; 7102824859; 36849130600; 6507924888The barium hexaferrite (BaFe12O19) containing magnetic poly (ethylene glycol dimethacrylate-vinyl pyridine; mag-poly [EGDMA-VP]) beads (average diameter = 53-212 mu m) were synthesized and characterized. Their use as an adsorbent in the removal of dimethyl phthalate (DMP) from an aqueous solution was investigated. The mag-poly (EGDMA-VP) beads were prepared by copolymerizing of 4-vinyl pyridine (VP) with ethylene glycol dimethacrylate (EGDMA). The mag-poly (EGDMA-VP) beads were characterized by N-2 adsorption/desorption isotherms (BET), vibrating sample magnetometer (VSM), X-ray powder diffraction (XRD), elemental analysis, scanning electron microscope (SEM), and swelling studies. At a fixed solid/solution ratio, the various factors affecting the adsorption of DMP from aqueous solutions such as pH, initial concentration, contact time, and temperature were analyzed. The maximum DMP adsorption capacity of the mag-poly (EGDMA-VP) beads was determined as 96.2 mg/g at pH 3.0, 25 degrees C. All the isotherm data can be fitted with both the Langmuir and the Dubinin-Radushkevich isotherm models. The pseudo-first-order, pseudo-second-order, Ritch-second-order, and intraparticle diffusion models were used to describe the adsorption kinetics. The thermodynamic parameters obtained indicated the exothermic nature of the adsorption. The DMP adsorption capacity did not change after 10 batch successive reactions, demonstrating the usefulness of the magnetic beads in applications.Item Design and in vivo evaluation of alginate-based pH-sensing electrospun wound dressing containing anthocyanins(Springer, 2021-02) Pakolpakçıl, Ayben; Osman, Bilgen; Göktalay, Gökhan; Özer, Elif Tümay; Şahan, Yasemin; Becerir, Behçet; Karaca, Esra; Uludağ Üniversitesi/Mühendislik Fakültesi/Tekstil Mühendisliği.; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; Uludağ Üniversitesi/Tıp Fakültesi/Farmakoloji Anabilim Dalı.; Uludağ Üniversitesi/Ziraat Fakültesi/Gıda Mühendisliği.; 0000-0002-6981-4980; 0000-0002-2655-2773; 0000-0003-1777-3977; 0000-0001-6261-4233; ADX-6657-2022; ABF-4791-2020; AAH-1448-2021; JIV-6630-2023; IHI-9909-2023; AAH-1445-2021; AAS-8480-2020; 57204420713; 15221651200; 6508023759; 37047586000; 25629856600; 9839809500; 17344029200In this study, a pH-sensing electrospun mat containing purple cabbage (PC) (Brassica oleracea) anthocyanins was developed for wound dressing application. The pH-sensing electrospun mat was prepared from sodium alginate (Alg) and poly (vinyl alcohol) (PVA) via electrospinning. PC anthocyanins were embedded into the electrospun mat with the addition of PC extract into the Alg/PVA electrospun solution. The characterization studies were conducted by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), water contact angle (WCA) and thickness measurements. The halochromic behavior of the pH-sensing Alg/PVA/PC electrospun mat was elucidated via UV-Vis spectrophotometric analyses and color measurements obtained from quantitative color data. In vivo performance of the pH-sensing mat was evaluated by animal studies. The electrospun mat was successfully used to monitor pH changes of an open wound. In addition, wound healing efficacy of the electrospun mat was compared with a commercial wound dressing. The results revealed that a wound dressing benefiting from halochromic properties of the anthocyanins besides wound healing efficacy of Alg was successfully developed. The pH-sensing Alg/PVA/PC electrospun mat has a usage potential for wound dressing applications especially for monitoring wound status on real-time during healing period.Item Development and application of a solid phase extraction method for the determination of phthalates in artificial saliva using new synthesised microspheres(Elsevier, 2013-06) Osman, Bilgen; Özer, Elif Tumay; Beşirli, Necati; Güçer, Şeref; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Anabilim Dalı.; 0000-0003-0610-2019; ABF-4791-2020; AAI-3137-2021; 15221651200; 37047586000; 6507924888; 36849130600This paper describes a method for the determination of six phthalate esters (PEs) in artificial saliva using solid phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS). A new material was developed to isolate the PEs from artificial saliva. Poly(ethylene glycol dimethacrylate-N-methacryloyl-L-tryptophan methyl ester) (poly(EGDMA-MATrp)) microspheres (average diameter = 106-300 mu m) were synthesised and characterised. Several different parameters, such as pH, adsorption time and adsorbent amount, which affect SPE, were carefully optimised by central composite design (CCD). The best analytical conditions for the simultaneous determination of the analytes from a spiked artificial saliva sample were found to be a pH of 6.8, an adsorption time of 90 min, and an adsorbent amount of 1.8 g L-1, using dichloromethane as the elution solvent. These conditions were applied to study the migration of PEs found on various children's toys into saliva.Item Development of a new solid phase extraction method for sensitive determination of some carbamate pesticides in water using poly(EGDMA-MATrp) microbeads(Elsevier, 2020-07-20) Demir, Özge; Ulusoy, Halil İbrahim; Özer, Elif Tümay; Osman, Bilgen; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; AAI-3137-2021; ABF-4791-2020; 37047586000; 15221651200In this work, poly(ethylene glycol dimethacrylate-N-methacryloyl-L-tryptophan methyl ester) [poly(EGDMA-MATrp)] microbeads (average diameter = 106-300 mu m), were synthesized by suspension polymerization technique. The microbeads showed strong affinity and allowed for solid phase extraction (SPE) of two common pesticides; pirimicarb and propoxur in environmental water samples. Some SPE process parameters such as the desorption solvent type, solvent volume, pH and salt concentration were optimized. When it was coupled with high pressure liquid chromatography (HPLC-PDA) for the determination of analytes, the linear ranges were about 10-800 ng mL(-1) and the detection limits were 0.95-2.85 ng mL(-1). Also the correlation coefficients (0.9949-0.9991) and precisions (2.15-2.52% RSD, n = 3) were determined. The technique was also applied to the enrichment of these pesticides in various environmental water samples. However, no target analyte was detected in the samples. Therefore, samples were spiked and recovery values were obtained in the range of 95.8-104.2% with RSDs of 2.6-6.6%.Item Diethyl phthalate removal from aqueous phase using poly(EGDMA-MATrp) beads: Kinetic, isothermal and thermodynamic studies(Taylor & Francis, 2015-07-03) Özer, Elif Tümay; Osman, Bilgen; Kara, Ali; Demirbel, Emel; Beşirli, Necati; Gücer, Şeref; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; 0000-0002-5225-0146; 0000-0001-8406-149X; 0000-0003-2457-6314; AAI-3137-2021; ABF-4791-2020; AAG-6271-2019; ESF-6302-2022; CGK-8659-2022; GAV-3362-2022; 37047586000; 15221651200; 7102824859; 54681740300; 6507924888; 36849130600In this study, poly(ethylene glycol dimethacrylate-N-methacryloyl-l-tryptophan methyl ester) [poly(EGDMA-MATrp)] beads (average diameter = 106-300 mu m), which were synthesized by co-polymerizing of N-methacryloyl-l-tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA), were used for diethyl phthalate (DEP) adsorption. The various factors affecting the adsorption of DEP from aqueous solutions such as pH, initial concentration, contact time and temperature were analysed. Adsorption behaviour of DEP on the poly(EGDMA-MATrp) beads was investigated by varying pH values of solution, contact time, initial concentration and temperature. An optimum adsorption capacity of 590.7 mg/g for DEP was obtained at 25 degrees C. The present adsorption process obeyed a pseudo-second-order kinetic model. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. Thermodynamic parameters Delta H = 7.745 kJ/mol, Delta S = 81.92 J/K/mol and Delta G = -16.69 kJ/mol to -18.31 kJ/mol with the rise in temperature from 25 degrees C to 45 degrees C indicated that the adsorption process was endothermic and spontaneous.Item Dummy molecularly imprinted microbeads as solid-phase extraction material for selective determination of phthalate esters in water(Elsevier, 2017-04-07) Özer, Elif Tümay; Osman, Bilgen; Yazıcı, Tuğçe; Uludağ Üniversitesi/Fen-Edebiyet Fakültesi/Kimya Bölümü.; AAI-3137-2021; ABF-4791-2020; 37047586000; 15221651200; 57193902495The aim of this study was to investigate the usability of newly synthesized dummy molecularly imprinted microbeads (DMIMs) as a solid phase extraction (SPE) material to determine six phthalate esters (PEs) in water by GC-MS analysis. Diethyl phthalate (DEP) was used as a dummy template to prepare poly(ethylene glycol dimethacrylate N-methacryloyl-L-tryptophan methyl ester) [PEMATrp)] DMIMs by using suspension polymerization. The PEMATrp DMIMs were characterized by using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Firstly, the adsorption capacities of the DMIMs prepared in different template molecule (DEP) to functional monomer (MATrp) ratios were investigated by using DEP solutions in the concentration range of 1-500 mg/L, at pH 3.0. Styrene and vanillic acid were used to evaluate the selectivity of the prepared DMIMs towards the template molecule (DEP). Then, the best analytical conditions were investigated for the simultaneous determination of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), benzylbutyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DnOP) in aqueous media by using the PEMATrp DMIMs as SPE material. Validation experiments showed that the PEMATrp DMIMs-SPE method had good linearity at 12.5-250.0 mu g/L (0.988-0.999), good precision (1.2-5.9%), and limits of detection in a range of 0.31-0.41 mu g/L.Publication Dummy molecularly imprinted polymer-based solid-phase extraction method for the determination of some phthalate monoesters in urine by gas chromatography-mass spectrometry analysis(Elsevier, 2023-11-24) Küçük, Melike; Osman, Bilgen; Özer, Elif Tumay; KÜÇÜK, MELİKE; OSMAN, BİLGEN; TÜMAY ÖZER, ELİF; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; 0000-0001-8406-149X; V-1616-2019; JCP-4547-2023; JME-2199-2023A dummy molecularly imprinted polymer-based solid-phase extraction (SPE) sorbent was used for the selective extraction of some phthalate monoesters, monoethyl phthalate (MEP), monobutyl phthalate (MnBP) and mono-(2-ethylhexyl) phthalate (MEHP) in urine prior to gas-chromatography-mass spectrometry (GC-MS) analysis. Diethyl phthalate (DEP), a phthalate ester, was successfully used as a dummy template to prepare selective sorbent for MEP, MnBP, and MEHP extraction. DEP-imprinted poly(ethylene glycol dimethacrylate N-meth-acryloyl-L-tryptophan methyl ester) (DPEMT) microbeads were synthesized by suspension polymerization and characterized by Fourier Transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and Brunauer Emmet Teller (BET) analysis. The critical parameters (i.e., pH, sorbent amount, ionic strength, sample volume, elution solvent) affecting the extraction performance of the DPEMT-SPE sorbent were optimized. Under optimum conditions, good linearities were obtained in the concentration range of 4 to 60 ng/mL with deter-mination coefficients (R2) of greater than 0.9959. The developed SPE method provided low limits of detection (LOD) of 0.05-1.20 ng/mL and limits of quantification (LOQ) of 0.18-4.01 ng/mL with relative standard de-viations (RSDs) of less than 8.95 % for intra-and inter-day analyses. The proposed SPE method was used to analyze phthalate monoesters in spiked urine samples, and recoveries of 97.45-109.26 % were obtained. DPEMT-SPE sorbent was reused for 15 times without any losses of performance. Consequently, a highly selective and sensitive SPE method based on a dummy molecularly imprinted polymer combined with GC-MS was suc-cessfully developed to monitor human phthalate exposure via urine samples.Item Evaluation of the effectiveness of microparticle-embedded cryogel system in removal of 17β-estradiol from aqueous solution(Desalination, 2016-07) Sarıkaya, Aslı Göçenoğlu; Osman, Bilgen; Kara, Ali; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; 0000-0002-7161-7003; 0000-0003-2457-6314; ABF-4791-2020; AAC-6901-2020; DVE-2249-2022; 56709610700; 15221651200; 7102824859In this study, we have synthesized microparticle-embedded cryogel system for removal of 17 beta-estradiol (E2). Firstly, the poly(hydroxyethyl methacrylate-N-methacryloyl-L-tryptophan methyl ester) poly(HEMA-MATrp) microparticles were produced by emulsion polymerization. And then, poly(HEMA-MATrp) microparticles were embedded in poly(hydroxyethyl methacrylate) cryogel and [PHEMA/MATrp] cryogel system was prepared. [PHEMA/MATrp] cryogel system was used for the removal of E2. The characterization studies of the poly(HEMA-MATrp) microparticles and cryogel system were conducted by infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and swelling studies. The effects of initial concentration, temperature, and contact time on adsorption of E2 were investigated. Maximum adsorption capacity of PHEMA/MATrp cryogel was determined as 2.75 mg E2/g cryogel at 25 degrees C. The adsorption process obeyed both pseudo-second-order and intraparticle diffusion kinetic models. All the isotherm data can be fitted Langmuir isotherm model with high correlation coefficients for all studied temperatures. Thermodynamic parameters Delta H degrees = 654.9 J/mol, Delta S degrees = 85.90 J/K/mol, and Delta G degrees = -23.14 to -26.23 kJ/mol with the rise in temperature from 4 to 40 degrees C indicated that the adsorption process was endothermic and spontaneous. The E2 adsorption capacity did not change after five batch successive adsorption-desorption cycles, demonstrating the usefulness of the microparticle-embedded cryogel system in applications.Item An experimental design approach for the solid phase extraction of some organophosphorus pesticides from water samples with polymeric microbeads(Elsevier, 2019-12-15) Özer, Elif Tümay; Osman, Bilgen; Parlak, Buse; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; AAI-3137-2021; ABF-4791-2020; DMT-3351-2022; 37047586000; 15221651200; 57212551570The aim of this study was to develop a solid phase extraction (SPE) method for extraction of eleven organophosphorus pesticides (OPPs) from water samples before gas chromatography-mass spectrometry (GC-MS) analysis. The poly(divinylbenzene-N-methacryloyl-L-tryptophan methyl ester) [PDMAT] microbeads synthesized via suspension polymerization of N-methacryloyl-L-tryptophan methyl ester and divinylbenzene (DVB) were used as an adsorbent for SPE of dichlorvos, diazinon, disulfoton, parathion-methyl, malathion, fenthion, chlorpyrifos, bromophos-methyl, chlorfenvinphos, bromophos-ethyl and ethion. A central composite design (CCD), combined with Derringer's desirability function (DF) approach was used for evaluation and optimization of various parameters affecting the extraction efficiency, such as adsorbent amount (g), pH and elution rate of the solvent. The mean relative recoveries for OPPs from the water matrices ranged from 69 to 139% with intra-day RSD of 0.58–8.17% and inter-day relative standard deviation (RSD) of 0.60–4.94%. The PDMAT-SPE method had a good linearity at 1-50 µg L−1 (R2≥0.987) concentration range and a limit of detection (LOD) in the range of 0.002−0.118 µg L−1, with the exception of diazinon (0.597 µg L−1). The developed SPE method demonstrated that it could be applied for the determination of OPPs in water samples.Item Halochromic composite nanofibrous mat for wound healing monitoring(IOP Publishing, 2019-12) Pakolpakcil, Ayben; Osman, Bilgen; Ozer, Elif Tumay; Sahan, Yasemin; Becerir, Behcet; Göktalay, Gökhan; Karaca, Esra; Bursa Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Tekstil Mühendisliği Bölümü.; 0000-0002-2655-2773; 0000-0003-1777-3977; 0000-0002-6981-4980; 0000-0001-8406-149X; AAI-3137-2021; ABE-6748-2020; AAH-1445-2021; AAS-8480-2020; AAH-1448-2021; AAH-1448-2021; ABF-4791-2020; 57204420713; 15221651200; 37047586000; 25629856600; 9839809500; 6508023759; 17344029200This study was focused on the development and characterization of a wound dressing for pH monitoring based on a sodium alginate (SA) and polyvinyl alcohol (PVA) nanofibrous mat including anthocyanins extracted from black carrot (BC). The pH-sensitive mat was prepared through the electrospinning method. The crosslinking of the nanofibrous mat was carried out using glutaraldehyde (GA). The functionalized PVA/SA/BC nanofibrous mat was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The colors of the nanofibrous mat resulting from pH changes were evaluated using a digital camera. The images were processed using Adobe Photoshop software, CS5 version, and analyzed through RGB and CIELAB. When the dried nanofibrous mat with a light pink color was immersed in buffer solutions at different pHs, the color of the nanofibrous mat ranged from red (in acidic medium) to blue (in neutral medium) and then to black-green (in basic medium). The response time and temperature stability of the nanofibrous mat were also investigated. It was concluded that the developed pH-sensing composite nanofibrous mat could be successfully used as wound dressing for monitoring healing.Item Immobilization of alpha-amylase on Cu2+ chelated poly(ethylene glycol dimethacrylate-n-vinyl imidazole) matrix via adsorption(Elsevier, 2005) Yavuz, Handan; Denizli, Adil; Kara, Ali; Osman, Bilgen; Beşirli, Necati; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Bölümü.Poly(ethylene glycol dimethacrylate-n-vinyl imidazole) [poly(EGDMA-VIM)] hydrogel (average diameter 150-200 pm) was prepared by copolymerizing ethylene glycol dimethacrylate (EGDMA) with n-vinyl imidazole (VIM). The copolymer hydrogel bead composition was characterized by elemental analysis and found to contain 5 EGDMA monomer units each VIM monomer unit. Poly(EGDMA-VIM) beads had a specific surface area of 59.8 m(2)/g. Poly- (EGDMA-VIM) beads were characterized by swelling studies and SEM. Cu2+ ions were chelated on the poly(EGDMA-VIM) beads, then these beads were used in the adsorption of alpha-amylase from Aspergillus Oryzae in batch system. The maximum alpha-amylase adsorption capacity of the poly(EGDMA-VIM)-Cu2+ beads was observed as 38.9 mg/g at pH 4.0. The K-m values for immobilized alpha-amylase (poly(EGDMA-VIM)-Cu2+) (22.5 mM) was higher than that of free enzyme (15.8 mM). Storage stability was found to increase with immobilization. It was observed that enzyme could be repeatedly adsorbed and desorbed without significant loss in adsorption capacity or enzyme activity.Item Immobilization of glucoamylase onto lewis metal ion chelated magnetic affinity sorbent: Kinetic, isotherm and thermodynamic studies(Taylor & Francis, 2011) Osman, Bilgen; Kara, Ali; Beşirli, Necati; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Anabilim Dalı.; AAG-6271-2019; ABF-4791-2020; 15221651200; 7102824859; 6507924888In this study, magnetic metal-chelate beads, m-poly(ethylene glycol dimethacrylate-vinyl imidazole) [m-poly(EGDMA-VIM)] with an average diameter 150-200 m was synthesized by copolymerizing ethylene glycol dimethacrylate (EGDMA) with vinyl imidazole (VIM). The spesific surface area of the m-poly(EGDMA-VIM) beads was found 63.1 m2/g. Cu2+ ions were chelated on the m-poly(EGDMA-VIM) beads and used in immobilization of Aspergillus niger glucoamylase in a batch system. The maximum glucoamylase adsorption capacity of the m-poly(EGDMA-VIM)-Cu2+ beads was observed as 120 mg/g at pH 6.5. The optimum pH for free and m-poly(EGDMA-VIM)-Cu2+ immobilized glucoamylase were found 4.0 and 4.5, respectively. The optimum temperature of glucoamylase was not changed after immobilization and determined as 60oC for free and immobilized enzyme preparations. The glucoamylase adsorption capacity and adsorbed enzyme activity slightly decreased after 10 batch successive reactions, demonstrating the usefulness of the enzyme-loaded beads in biocatalytic applications. Storage stability was found to increase with immobilization. The effect of various experimental parameters such as pH, glucoamylase concentration, contact time and temperature in aqueous solution were also investigated. Adsorption isotherm obtained for m-poly(EGDMA-VIM)-Cu2+ was consistent with Langmuir model. Kinetic studies showed that the adsorption process agreed with both the pseudo-second-order kinetic model and the modified Ritchie's-second-order kinetic model. Various thermodynamic parameters, free energy (G0), enthalpy (H0) and entropy (S0), were also calculated and the results showed that the adsorption process strongly depended on temperature of medium.Item Immobilization of horseradish peroxidase enzyme onto polymeric microbeads and its usage in dye decolorization(Bursa Uludağ Üniversitesi, 2023-07-04) Zhumabekova, Altynay; Osman, Bilgen; Bursa Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Kimya Anabilim Dalı.; 0009-0006-4332-8868In this study, horseradish peroxidase (HRP) enzyme was immobilized onto poly(ethylene glycol dimethacrylate-N-methacryloyl-amido-L-tryptophan methyl ester) [PEDMT] microbeads by adsorption method and used in decolorization of Congo red (CR) and Reactive Black 5 (RB5) dyes. The microbeads were characterized by Brunauer–Emmett– Teller (BET) analysis, Fourier Transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX). Immobilization yield, activity yield, and immobilization efficiency were determined and had a value of 84.86 ± 2.06%, 73.78 ± 5.91%, and 86.95 ± 6.92%, respectively. Relative activities of free and immobilized enzymes were compared, and optimum reaction conditions were determined as pH 6.0, 3% H₂O₂ concentration, and temperature of 50 °C for PEDMT-HRP and 40 °C for free HRP. The effect of metal ions and organic solvents, thermal and storage stability of enzymes were estimated. Also, it was possible to reuse PEDMT-HRP for ten cycles with 55% of the remaining activity. The decolorization studies were performed and the effects of pH, microbeads amount and enzyme concentration, H₂O₂ and dye concentration, and contact time were indicated. The best decolorization was obtained at pH 6.0, 25 mg/L dye concentration, 3% H₂O₂ concentration, and 2 h of contact time for both enzymes. PEDMT-HRP preserved 44% of activity after the ten cycles with CR and 17% after the five cycles with RB5. Moreover, decolorization was followed via HPLC analysis. The results revealed that PEDMT-HRP could simultaneously decolorize both dyes with 94% (CR) and 29% (RB) efficiency, but the free enzyme displayed 4.5% decolorization.
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