Person: OSMAN, BİLGEN
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
OSMAN
First Name
BİLGEN
Name
5 results
Search Results
Now showing 1 - 5 of 5
Publication Superhydrophobic surface based on cross-linked polymer(Iop Publishing Ltd, 2019-05-01) Osman, Bilgen; OSMAN, BİLGEN; Aydemir, Tuğba Gün; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi; 0000-0001-8406-149X; ABF-4791-2020The aim of this study was to prepare a superhydrophobic surface by coating poly(divinylbenzene-N-methacryloyl-amido-L-phenylalanine ethyl ester) [poly(DVB-MAPA)] cross-linked polymer onto a glass surface. N-methacryloyl-amido-L-phenylalanine ethyl ester (MAPA) and 1, 4-divinylbenzene (DVB) were used as a monomer and a cross-linker, respectively. The polymerization mixture was dispersed in 1, 4 butanediol (BDO) for phase separation and polymerized on the glass surface. The superhydrophobic surface was characterized with Fourier transform infrared spectroscopy (FTIR), x-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and contact angle measurements. The effect of the composition of a polymerization mixture on hydrophobicity was investigated by varying the cross-linker to monomer mol ratio. Additionally, the influence of the composition of monomer/BDO mixtures was determined. The prepared poly(DVB-MAPA) surface showed a superhydrophobicity with a high water contact angle (WCA) of 162 degrees and a low sliding angle (SA) of 7 degrees . Moreover, the poly(DVB-MAPA) surface has a good chemical, thermal and daylight stability.Publication Molecularly imprinted solid-phase extraction sorbent for selective determination of melatonin(Elsevier, 2021-07-30) Esen, Elif; Osman, Bilgen; Demir, M. Nalan; OSMAN, BİLGEN; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü; 0000-0001-8406-149X; ABF-4791-2020In this study, melatonin (MLT)-imprinted poly (ethylene glycol dimethacrylate-N-methacryloyl-L-tryptophan methyl ester) [MLT-PEMATrp] microbeads were prepared for solid phase extraction (SPE) of melatonin (MLT) from edible plants prior to high performance liquid chromatography (HPLC) analysis. The microbeads were prepared via molecular imprinting technique by using MLT as a template. The MLT-PEMATrp microbeads were characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermal gravimetic analysis (TGA), N2 adsorption/desorption isotherms and swelling test. The parameters such as adsorption time, temperature, adsorbent amount, pH and ionic strength were detailedly optimized to increase the effciency of MLT adsorption procedure. The adsorption properties of MLT onto the MLT-PEMATrp microbeads (MIP) and non-imprinted PEMATrp microbeads (NIP) were investigated to show the effectiveness of imprinting. MIP showed higher adsorption capacity for MLT (QMIP = 207.71 mg g-1) than NIP (QNIP = 12.15 mg g-1). The relative selectivity coefficients calculated for serotonin (3.41) and L-tryptophan (5.94) indicated that MLT-PEMATrp microbeads exhibit significantly high selectivity for MLT. The microbeads were used for SPE of MLT from Linden (Tilia tomentosa), fennel (Foeniculum Vulgare), sage (Salvia officinalis) and chamomilla (Matricaria chamomilla) samples prior to HPLC analysis. The recoveries of MLT in the samples were in the range of 90-103.4%. The SPE method had a limit of detection (LOD) in the range of 0.026-0.094 mu g mL-1. The MLTPEMATrp microbeads was very effective for SPE of MLT.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.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.