Yazar "Ilktac, Raif" seçeneğine göre listele
Listeleniyor 1 - 11 / 11
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Chamotte Clay: A Natural Adsorbent for Separation and Preconcentration of Aluminium(2023) Ilktac, RaifThe adsorption behavior of aluminium ions on chamotte clay has been studied in this study. Chamotte clay has been used for the first time for determination of trace levels of aluminium in aqueous solutions. Quantitative adsorption and recovery of aluminium were both rapid and reached an equilibrium in 30 minutes. Aluminium was detected based on the formation of the highly fluorescent Al(III)-morin complex. Two linear calibration graphs were obtained in the range of $0.5-10 µg L^{-1} and 10-100 µg L^{-1}$ with the detection limits of $0.12 µg L^{-1} and 1.12 µg L^{-1}$, respectively. Chamotte clay was characterized by scanning electron microscope coupled with energy-dispersive X-ray spectroscopy, energy dispersive X-ray fluorescence and X-ray photoelectron spectroscopy techniques. Different isotherm models were evaluated and the results showed that the adsorption study was fitted to Freundlich isotherm and a favorable and multilayer adsorption of aluminium was occurred on the heterogeneous surface of the chamotte clay. Thermodynamic and kinetic parameters of aluminium adsorption were also investigated. Various experimental parameters were optimized and the method has been applied to tap and bottled drinking water samples and quantitative recoveries were obtained. The results demonstrated that the chamotte clay, as a natural clay, was expected to be a promising adsorbent for the determination and preconcentration of the trace levels of analyte in real samples.Öğe Development of rapid, sensitive and selective fluorimetric method for determination of 1-naphthalene acetic acid in cucumber by using magnetite-molecularly imprinted polymer(Pergamon-Elsevier Science Ltd, 2019) Ilktac, Raif; Gumus, Zinar Pinar; Aksuner, NurIn this study, a novel method based on the determination of 1-naphthalene acetic acid with the usage of magnetite-molecularly imprinted polymer prior to fluorimetric detection has been developed. Magnetite-molecularly imprinted polymer has been used for the first time as selective adsorbent for the determination of 1-naphthalene acetic acid. the adsorption capacity of the synthesized polymer was found to be 2.18 +/- 0.36 mg g(-1) (n = 3). Limit of detection (LOD) and limit of quantification (LOQ) of the method were found to be 0.75 and 2.50 mu g L-1, respectively. Linearity of the calibration graph for the proposed method was observed within the range of 20-700 mu g L-1. the proposed method seems to be rapid where the detection procedure for 1-naphthalene acetic acid can be completed within a total time of 1 h. the same imprinted polymer can be used for the determination of 1-naphthalene acetic acid with quantitative sorption and recovery values repeatedly for at least ten times. the effects of some potential organic interferences were investigated. Proposed method has been successfully applied to determine 1-naphthalene acetic acid in cucumber, where the recoveries of the spiked samples were found to be in the range of 93.7-104.5%. Characterization of the synthesized polymer was also evaluated. By combining the high capacity, cheapness, reusability and selectivity of the magnetic adsorbent with the dynamic calibration range, rapidity, simplicity, and sensitivity of fluorimetry, the proposed method seems to be an ideal method for the determination of trace levels of 1-naphthalene acetic acid. (c) 2019 Elsevier B.V. All rights reserved.Öğe A Fluorimetric Method Based On Magnetic Molecularly Imprinted Polymer For Selective Detection Of Chlorferon(Springer/Plenum Publishers, 2022) Ilktac, RaifIn the present work, reusable magnetic molecularly imprinted polymers have been used for the first time as an adsorbent for the determination of chlorferon. Magnetic molecularly imprinted polymers have been used for the selective separation of chlorferon from the solution and sensitive fluorimetric determination has been performed using the native fluorescence of chlorferon. The developed method is rapid and determination of chlorferon was completed in an hour. Limit of detection (LOD) of the method was found to be 0.0027 mu M and the linearity of the calibration graph was observed within the range of 0.01-0.36 mu M (2.5 - 75 mu g L-1). Adsorption isotherms point out the multilayer adsorption and the heterogeneous distribution of binding sites for imprinted polymer and homogeneous binding site for non-imprinted polymer. The adsorption capacities of imprinted polymer and non-imprinted polymer were calculated as 2.03 mu mol g(-1) and 0.96 mu mol g(-1), respectively and the imprinting factor was found to be 2.11. The interference effects of some organic compounds and characterization studies were also evaluated. The method has been applied to honey and tap water samples and the recoveries were found to be in the range of 91.3 and 101.1 %.Öğe A Functional Platform for the Detection of JWH-073 as a Model for Synthetic Cannabinoids(Wiley-V C H Verlag Gmbh, 2018) Sengel, Tulay Yilmaz; Celik, Emine Guler; Aydogan, Cansu; Gumus, Zinar Pinar; Ilktac, Raif; Aydindogan, Eda; Ciftci, Mustafa; Aldemir, Ebru; Coskunol, Hakan; Timur, Suna; Yagci, YusufDuring the last decade, progress has been made in the on-site detection of abused drug use. Herein, we present an electrochemical biosensor for the detection of one of the synthetic cannabinoids (SCs), JWH-073, using poly (methyl methacrylate) (PMMA) hyperbranched copolymer (HBC) as a base coating and antibody molecules to bind the JWH-073 to the surface. Modification of the surface is proved with various techniques such as differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectrometry. The limit of detection and linearity (in logarithmic scale) for JWH-073 were found to be 31.87 ng/mL and 25-500 ng/mL, respectively. The selectivity of the proposed biosensor was also tested in the presence of interfering molecules and the response was much higher for JWH-073 in all measurements. In the final part of the study, synthetic urine was tested with the device and the relative standard deviation value was calculated to be less than 5.0%. The confirmation of data from the resulting bio-platform was performed via LC-QTOF/MS. This work is the first of its kind, a novel, rapid, cost-effective sensing platform for the detection of the SC.Öğe Highly sensitive and selective method for the rapid determination and preconcentration of haloperidol by using a magnetite-molecularly imprinted polymer(Wiley-V C H Verlag Gmbh, 2019) Ilktac, Raif; Gumus, Zinar Pinar; Aksuner, Nur; Coskunol, HakanA sensitive and selective method based on the determination of haloperidol with the usage of magnetite-molecularly imprinted polymer and high-resolution liquid chromatography has been developed. This novel method is rapid as the detection procedure for haloperidol can be completed within a total time of 1 h. The same imprinted polymer can be used for the determination of haloperidol at least 20 times. The proposed method has been succesfully applied to synthetic urine and serum samples and the recoveries of the spiked samples were in the range of 94.7-100.7%. The limit of detection and limit of quantification of the method were 2.25 and 7.50 mu g/L, respectively. Linearity of the calibration graph was observed within the range of 10-250 mu g/L. By combining the high capacity, high selectivity, and reusability of the magnetic adsorbent with the dynamic calibration range, high sensitivity and high resolution of liquid chromatography with quadrupole time-of-flight mass spectrometry, the proposed method is an ideal method for the determination and preconcentration of trace levels of haloperidol. A magnetite-molecularly imprinted polymer has been used for the first time as a selective adsorbent for the determination of haloperidol.Öğe Magnetic Nanofiber Layers as a Functional Surface for Biomolecule Immobilization and One-Use 'Sensing in-a-Drop' Applications(Wiley-V C H Verlag Gmbh, 2018) Sanli, Serdar; Celik, Emine Guler; Demir, Bilal; Gumus, Z. Pinar; Ilktac, Raif; Aksuner, Nur; Demirkol, Dilek Odaci; Timur, SunaStabilization of biomolecules on matrices is critically important. Here we constructed composite nanofibers with magnetic features by electro-spinning of magnetic nanoparticles (MNP) in an appropriate polymer matrix on a collector surface for multiple uses. 'Poly(vinylalcohol)-polyethyleneimine/Fe3O4 magnetic nanoparticles' (PVA-PEI/MNP) composite nanofiber was used on the screen printed electrodes (SPE) to serve as a platform for the glucose oxidase (GOx) biofilm as the model biomolecule. To show the potential application of this material as a biosensor component, the resulted biofilm, called 'PVA-PEI/MNP/GOx', was fixed on SPE via a neodymium magnet for the electrochemical detection of glucose at -0.7 V where oxygen consumption due to enzymatic reaction was measured. The main advantage of the obtained magnetic biomembrane is that it allows analysis with a single drop. After step-by-step surface modifications, analytical characterization was performed using various techniques, such as voltammetry, electrochemical impedance spectroscopy, Fourier-transform infrared spectroscopy and X-Ray photoelectron spectroscopy as well as microscopic techniques. The linear range of the PVA-PEI/MNP/GOx surface was found as 0.0125 to 0.5 mM with a limit of detection of 11.5 mu M for glucose as analyte. The application of PVA-PEI/MNP/GOx for glucose detection in synthetic samples was carried out. Data proved the potential use of the 'PVA-PEI/MNP' surface as a biomolecule immobilization platform for disposable biosensor applications.Öğe Magnetite-molecularly imprinted polymer based highly sensitive chromatographic method for preconcentration and determination of pirimicarb(Taylor & Francis Ltd, 2020) Ilktac, Raif; Gumus, Zinar PinarPesticides are harmful compounds even in trace levels for human health, so the importance of determination of these compounds is increasing day by day. Magnetite-molecularly imprinted polymer and high resolution liquid chromatography has been combined for the preconcentration and sensitive and selective determination of trace levels of pirimicarb. the developed method appeared to be rapid since the total procedure for detection of pirimicarb can be completed within one hour. the magnetic polymer is reusable and the same polymer can be used at least ten cycles for detection of pirimicarb. Limit of detection (LOD) of the method was found to be 1.60 mu g L-1 within the linear range of 7.5-250 mu g L-1. Proposed method has been applied to water and apple samples and quantitative recovery values were obtained. the proposed method appeared to be suitable for both preconcentration and determination of trace levels of pirimicarb by combining the selectivity of the reusable imprinted polymer with the high sensitivity of liquid chromatography-quadrupole-time-of-flight mass spectrometry. Magnetite-molecularly imprinted polymer combined with high resolution chromatography has been used for the first time for the determination of pirimicarb.Öğe Photopolymerization and characterization of vinyl imidazole based allyl derivative polymers; Cr3+ and Cd2+ metal adsorption and antibacterial studies(Wiley, 2024) Saltan, Fehmi; Saltan, Goezde Murat; Ilktac, Raif; Ozdokur, Kemal VolkanA new type polymeric adsorbent, poly(allylphenol-co-hydroxyethyl methacrylate-co-vinyl imidazole) (PAHV), is synthesized in this study. 2-Hydroxyethyl methacrylate is used as complementary monomers along with 1-vinyl imidazole and allylphenol monomers. The photopolymerization method is preferred as a synthesis method and benzophenone is used as the photoinitiator. The effectiveness of the PAHV against bacterial species such as Escherichia coli and Staphylococcus aureus is investigated by the Clinical and Laboratory Standards Institute (CLSI) disk diffusion method. The inhibition areas of PA(1)H(1)V(3) and PA(1)H(1)V(1) derivatives against E. coli and S. aureus are measured as 25 mm +/- 0.25 mm and 7 mm +/- 0.1 mm; 20 mm +/- 0.25 mm, and 5 mm +/- 0.1 mm, respectively. Sorption efficiencies (%) at pH = 6 (selected optimum pH) for 100 mu g/L Cd and Cr of the PA(1)H(1)V(1), PA(1)H(3)V(1), and PA(1)H(1)V(3) derivatives are found to be 69.0 +/- 2.7 and 58.3 +/- 6.7, 66.8 +/- 6.2 and 75.8 +/- 5.5, and 97.2 +/- 3.7 and 97.7 +/- 3.2 (n = 3), respectively. Adsorption studies revealed that the PA1H1V3 polymer can be used as an alternative for the sorption of cadmium and chromium. The pseudo-second-order model and Langmuir isotherm model fits for both adsorption processes. The adsorption capacities obtained from the Langmuir isotherm model for chromium and cadmium sorption are 52.63 and 68.49 mu g g(-1), respectively.Öğe Preconcentration and Fluorimetric Determination of 2-Phenylphenol using Magnetic Molecularly Imprinted Polymer(2022) Ilktac, RaifIn the present work, reusable magnetic molecularly imprinted polymers have been used for the first time as an adsorbent for the determination of 2-phenylphenol. Magnetic molecularly imprinted polymers have been used for the selective separation and preconcentration of 2-phenylphenol and native fluorescence has been used for the sensitive determination ofthe analyte. The developed method is rapid and determination of 2-phenylphenol was completed in 40 minutes. Limit of detection (LOD) of the method was found to be 1.09 µg L-1 and the imprinting factor was found to be 1.87. The linearity of the calibration graph was observed within the range of 5 - 250 µg L-1. Selectivity parameters showed that the specific binding sites were available on the imprinted polymer which was capable of recognizing 2-phenylphenol molecules with their functional groups, size and shape. Scatchard analysis revealed the heterogeneous distribution of binding sites for imprinted polymer and homogeneous binding site for non-imprinted polymer. The interference effects of some organic compounds and characterization studies were also evaluated. The method is applied to tap water samples and the recoveries were found to be in the range of 95.3 and 99.7 %.Öğe Rapid removal of crystal violet and methylene blue from aqueous solutions using chamotte clay(Springer Wien, 2023) Ilktac, RaifThis study focuses on the investigation of adsorption behavior of chamotte clay for the removal of two cationic dyes crystal violet and methylene blue from aqueous solutions. Chamotte clay has been used for the first time for the removal of cationic dyes. Chamotte clay was characterized successfully using scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDX), energy-dispersive X-ray fluorescence (EDXRF), and X-ray diffraction (XRD) techniques. Quantitative sorption of crystal violet and methylene blue were both rapid and reached an equilibrium in 15 and 30 min, respectively. Spectrophotometric determination of cationic dyes was carried out within the linear range of 0.5-50 mg dm(-3). Both sorption processes fit to Langmuir isotherm which can be concluded that a monolayer sorption of dye molecule was occurred. 1 and 5 g dm(-3) minimum adsorbent dose should be used for the quantitative sorption of crystal violet and methylene blue, respectively. Acetic acid can be used for the quantitative recoveries of the dyes. Kinetics and the thermodynamic parameters of the sorptions were also determined. Both sorption procedures can be defined as spontaneous and favorable physical sorption processes. Capacity of chamotte clay for crystal violet and methylene blue was determined as 65.8 mg g(-1) and 27.3 mg g(-1), respectively. The results showed that chamotte clay would be an ideal adsorbent for the separation and removal of cationic dyes from aqueous solutions and could have a wide practical use in the industrial wastewater treatment. [GRAPHICS]Öğe Vortex-assisted solid phase extraction on MIL-101(Cr) of parabens in waters and cosmetics by HPLC-DAD(Springer, 2023) Yengin, Cigdem; Gumus, Zinar Pinar; Ilktac, Raif; Elci, Aydan; Soylak, MustafaIn this study, metal organic framework MIL-101 (Cr) was used as an adsorbent in the solid phase extraction of parabens before chromatographic analysis. Analytical parameters including pH, adsorption-desorption time, amount of adsorbent, elution solvents, desorption volume and salt effect were optimized. Optimum adsorbent amount and total adsorption and desorption time for determination of parabens were found to be 15 mg and only 10 min. The recovery values obtained with this method are in the range of 90.78-104.89% for water matrix and 85.19-108.35% for cosmetics. The detection limits of the HPLC method for methyl, ethyl, propyl, and butyl parabens are 0.0387, 0.0322, 0.0299, and 0.0339 ug/mL, respectively. Prior to HPLC analysis, a new, fast, inexpensive, and environmentally friendly solid phase extraction method based on vortex-assisted MIL-101 (Cr) adsorption was developed. This proposed VA-SPE-HPLC procedure was used for the extraction and determination of four different parabens from water and cosmetic samples.
