Yazar "Mulazimoglu, Ibrahim Ender" seçeneğine göre listele

Listeleniyor 1 - 15 / 15
  • Küçük Resim Yok
    Öğe
    Carbonaceous Materials-12: a Novel Highly Sensitive Graphene Oxide-Based Carbon Electrode: Preparation, Characterization, and Heavy Metal Analysis in Food Samples
    (Springer, 2016) Yavuz, Samet; Erkal, Asli; Kariper, Ishak Afsin; Solak, Ali Osman; Jeon, Seungwon; Mulazimoglu, Ibrahim Ender; Ustundag, Zafer
    Graphene oxide (GO) was covalently attached to glassy carbon (GC) electrode (GC-O-GO) for fabricating nanosensors to determine trace Pb2+ and Cd2+ using differential pulse anodic stripping voltammetry (DPASV). Surface characterization of the nanofilm-covered electrode was performed via electrochemical cyclic voltammetry (CV), transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques. Surface pKa of the GO covalent attached GC (GC-O-GO) was calculated via CV. Under optimal conditions, a linear response was found for Pb2+ and Cd2+ in the range from 1 x 10(-8) to 1 x 10(-12) M. The limit of detections (LODs) of Pb2+ and Cd2+ were 0.25 pM and 0.28 pM, respectively. The method shows good reproducibility, and stability was successfully applied to measure Pb2+ and Cd2+ levels in rice, soya, milk, and tap water samples, with good agreement with those obtained by the standard inductively coupled plasma optical emission spectrometry (ICP-OES) method. The method was evaluated by application with the simultaneous determination of the ions in food samples (n = 6) using the standard addition method. The recoveries of the Pb2+ and Cd2+ were up to 98 %.
  • Küçük Resim Yok
    Öğe
    A Comparative Study of Electrochemical Behaviors of 1-nitroso-2-naphthol on Glassy Carbon and Platinum Electrode Surfaces by Cyclic Voltammetry
    (Univ Tehran, Fac Chemistry, Center Excellence Electrochemistry, 2012) Mulazimoglu, Aysen Demir; Yilmaz, Ecir; Mercimek, Bedrettin; Mulazimoglu, Ibrahim Ender
    In the present work, electrochemical and spectroelectrochemical behaviors of 1-nitroso-2-naphthol has been studied by cyclic voltammetry and electrochemical impedance spectroscopy techniques in non-aqueous media. Cyclic voltammetric studies of 1-nitroso-2-naphthol in acetonitrile containing 100 mM tetrabutylammonium tetrafluoroborate on glassy carbon and platinum electrodes were performed between 0.0 mV and +2600 mV potential range at 100 mV s(-1) scan rate with 10 cycles. Anodic peaks were observed at 475.3 mV, 958.9 mV, 1395 mV and 2103 mV for 1-nitroso-2-naphthol on the glassy carbon electrode surface vs. Ag/Ag+ reference electrode. The surface characterizations were carried out by using cyclic voltammetry and electrochemical impedance spectroscopy techniques in both aqueous and non-aqueous media. Electrochemical behaviors of 1-nitroso-2-naphthol on glassy carbon and platinum electrode surfaces were compared.
  • Küçük Resim Yok
    Öğe
    Determination of carcinoembryonic antigen (CEA) by surface plasmon resonance-enhanced total internal reflection ellipsometry (SPRe-TIRE)
    (Taylor & Francis Inc, 2024) Erkal-Aytemur, Asli; Sahin, Samet; Ustundag, Zafer; Mulazimoglu, Ibrahim Ender; Caglayan, Mustafa Oguzhan
    A surface plasmon resonance-enhanced total internal reflection ellipsometric (SPRe-TIRE) aptasensor is reported for the determination of the carcinoembryonic antigen (CEA). A gold nanofilm-coated SF10 glass slide was modified with electrochemical diazonium salt reduction and gold nanoparticles (AuNPs) to form a sensor. Next, a specific aptamer for CEA was immobilized on the AuNPs via self-assembly. The platform was characterized by X-ray photoelectron spectroscopy, ellipsometry, and cyclic voltammetry for each step of the preparation of the sensor. CEA aptamers with different affinities were used. SPRe-TIRE employed total internal reflection geometry and AuNPs to enhance plasmon resonance for the sensitive and selective determination of CEA in human serum. The working range of the aptasensor was from 0.01 to 500 ng/mL with an optimum detection limit of 0.1 pg/mL.
  • Küçük Resim Yok
    Öğe
    Determination of copper ions based on newly developed poly-chrysin modified glassy carbon sensor electrode
    (Walter De Gruyter Gmbh, 2012) Mulazimoglu, Aysen Demir; Mulazimoglu, Ibrahim Ender; Yilmaz, Ecir
    In this paper, glassy carbon (GC) was modified through the electrochemical polymerization of chrysin (PolyChr/GC) on the surface in media where the electrode surface was aqueous and non-aqueous. Electrochemical polymerization was performed between +800 mV and +2600 mV in aqueous medium, and from +500 mV to +1800 mV in non-aqueous medium in 100 mV s(-1) sweep rate with 30 cycles. Modified electrode surface characterization was done by cyclic voltammetry and electrochemical impedance spectroscopy. In the study, the interaction between the PolyChr/GC electrode surface and Cu(II), Zn(II), Cd(II), Pb(II), Co(II) and Ni(II) ions was investigated by using the square wave voltammetry technique. The PolyChr/GC electrode surface was found to be sensitive and selective towards Cu(II), Pb(II) and Cd(II) ions.
  • Küçük Resim Yok
    Öğe
    Determination of copper ions based on newly developed poly-chrysin modified glassy carbon sensor electrode
    (Walter De Gruyter Gmbh, 2012) Mulazimoglu, Aysen Demir; Mulazimoglu, Ibrahim Ender; Yilmaz, Ecir
    In this paper, glassy carbon (GC) was modified through the electrochemical polymerization of chrysin (PolyChr/GC) on the surface in media where the electrode surface was aqueous and non-aqueous. Electrochemical polymerization was performed between +800 mV and +2600 mV in aqueous medium, and from +500 mV to +1800 mV in non-aqueous medium in 100 mV s(-1) sweep rate with 30 cycles. Modified electrode surface characterization was done by cyclic voltammetry and electrochemical impedance spectroscopy. In the study, the interaction between the PolyChr/GC electrode surface and Cu(II), Zn(II), Cd(II), Pb(II), Co(II) and Ni(II) ions was investigated by using the square wave voltammetry technique. The PolyChr/GC electrode surface was found to be sensitive and selective towards Cu(II), Pb(II) and Cd(II) ions.
  • Küçük Resim Yok
    Öğe
    Dithiooxamide Modified Glassy Carbon Electrode for the Studies of Non-Aqueous Media: Electrochemical Behaviors of Quercetin on the Electrode Surface
    (Mdpi Ag, 2012) Mulazimoglu, Aysen Demir; Yilmaz, Ecir; Mulazimoglu, Ibrahim Ender
    Electrochemical oxidation of quercetin, as an important biological molecule, has been studied in non-aqueous media using cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy. To investigate the electrochemical properties of quercetin, an important flavonoid derivative, on a different surface, a new glassy carbon electrode has been developed using dithiooxamide as modifier in non-aqueous media. The surface modification of glassy carbon electrode has been performed within the 0.0 mV and +800 mV potential range with 20 cycles using 1 mM dithioxamide solution in acetonitrile. However, the modification of quercetin to both bare glassy carbon and dithiooxamide modified glassy carbon electrode surface was carried out in a wide +300 mV and +2,800 mV potential range with 10 cycles. Following the modification process, cyclic voltammetry has been used for the surface characterization in aqueous and non-aqueous media whereas electrochemical impedance spectroscopy has been used in aqueous media. Scanning electron microscopy has also been used to support the surface analysis. The obtained data from the characterization and modification studies of dithioxamide modified and quercetin grafted glassy carbon electrode showed that the developed electrode can be used for the quantitative determination of quercetin and antioxidant capacity determination as a chemical sensor electrode.
  • Küçük Resim Yok
    Öğe
    Electrochemical Behaviors of 2-Amino-3-Hydroxypyridine onto the Glassy Carbon Sensor Electrode: Simultaneous and Independent Determinations of Quercetin, Galangin, 3-Hydroxyflavone, and Chrysin
    (Springer, 2013) Mulazimoglu, Aysen Demir; Mulazimoglu, Ibrahim Ender
    Flavonoids, with high antioxidant activity in fruits and vegetables, are natural vegetable dyes synthesized from phenylalanine. They are very essential for human health due to their activity as free radical acceptors. In this paper, the availability in the determination of quercetin (Que), galangin (Gal), 3-hydroxyflavone (3HF), and chrysin (Chr) of a modified glassy carbon (GC) sensor electrode using 2-amino-3-hydroxypyridine (AHP) was examined separately and simultaneously by cyclic voltammetry (CV). Surface characterization of modified electrodes was performed using CV, electrochemical impedance spectroscopy, and scanning electron microscopy techniques. The modification of AHP onto the GC electrode surface was carried out between -150 and +600 mV potential range using 100 mV s(-1) scanning rate with 30 cycles. The binding of flavonoid derivatives onto the modified surface was performed between +300 and +1,700 mV potential range using 100 mV s(-1) scanning rate with 10 cycles. The usability of the modified electrode was examined in the determination of some flavonoids by square wave voltammetry. From the experimental results, it was found out that Que, 3HF, and Chr; Gal, 3HF, and Chr; and 3HF and Chr can be determined simultaneously by using an AHP-modified GC sensor electrode. Also, these molecules can easily be determined separately by using the modified electrode.
  • Küçük Resim Yok
    Öğe
    Electrochemical determination of copper(II) ions at naringenin-modified glassy carbon electrode: application in lake water sample
    (Desalination Publ, 2012) Mulazimoglu, Ibrahim Ender
    Electrochemical modification of glassy carbon (GC) electrode by naringenin (NG), a flavonoid derivative, and applicability of electrode modified in this way for determination of copper(II) (Cu(II)) ions is reported in this study. Surface modification experiments were performed in phosphate buffer solution (PBS), pH 7, in the 0.0 mV and +1400 mV potential ranges with a sweep rate of 100 mV s(-1) and 30 cycles. The surface modification of GC electrode was performed with NG using cyclic voltammetry (CV), whereas the characterization of this sensor electrode was performed using CV and electrochemical impedance spectroscopy (EIS). The sensitivity of GC electrode modified in described way towards Cu(II) ions was investigated in Britton-Robinson (BR) buffer solution, pH 5, by differential pulse voltammetry (DPV). For the calibration curve, a series of standard Cu(II) solution from 1.0 x 10(-12) M to 1.0 x 10(-6) M was prepared. The NG modified GC (NG/GC) sensor electrode, has a good repeatability, was applied for Cu(II) ions determination in Beysehir lake (in Konya, Turkey) water sample. Detection limit was obtained as lower as 1.0 x 10(-12) M. The proposed method was simple, rapid, low cost and sensitive for the determination of Cu(II) ions.
  • Küçük Resim Yok
    Öğe
    Electrochemical Grafting by Reduction of 4-Methylaminobenzenediazonium Salt at GC, Au and Pt Electrode: Investigation of Sensitivity Against Phenol by Cyclic Voltammetry
    (Univ Tehran, Fac Chemistry, Center Excellence Electrochemistry, 2012) Mulazimoglu, Aysen Demir; Mulazimoglu, Ibrahim Ender; Mercimek, Bedrettin
    The aim of this study is to modify a glassy cabon, gold and platinum electrode with 4-methylaminobenzenediazonium salt (MABDAS) to evaluate the possible application on the detection of phenol by cyclic voltammetry (CV). Diazonium salt was reduced electrochemically and covalently electro-grafted onto GC, Au and Pt electrodes surface to form modified electrodes in non-aqueous media. The electrode surfaces were modified with MABDAS in acetonitrile (CH3CN). MAB modified GC (MAB/GC) electrode was used for the phenol determination in aqueous media. The effect of pH on the electrochemical behavior of the modified GC electrode was investigated for the phenol detection.
  • Küçük Resim Yok
    Öğe
    Electrochemical Properties of MDA/GC Electrode and Investigation of Usability as Sensor Electrode for Determination of Que, Kae, Lut and Gal Using CV, DPV and SWV
    (Springer, 2013) Mulazimoglu, Aysen Demir; Mulazimoglu, Ibrahim Ender
    Flavonoids, natural vegetable dyes synthesized from phenylalanine, are responsible for the colour of blooming portions of plants. They are very essential for human health due to their activity as free radical acceptors. In this study, electrochemical modification of a glassy carbon (GC) electrode with 4,4'-methylenedianiline (MDA) was carried out, and the modified electrode was investigated separately and simultaneously for the availability in determination of quercetin, kaempferol, luteolin and galangin. The surface modification of the GC electrode was performed with MDA using cyclic voltammetry (CV), whereas the characterization of this sensor electrode was performed using CV, electrochemical impedance spectroscopy and scanning electron microscopy. The usability of the modified electrode has been examined in the determination of some flavonoids using CV, differential pulse voltammetry and square wave voltammetry. Consequently, flavonoid derivatives can easily be determined separately and simultaneously by using an MDA-modified GC sensor electrode.
  • Küçük Resim Yok
    Öğe
    Elemental monitoring of street dusts in Konya in Turkey
    (Elsevier, 2019) Kariper, I. Afsin; Ustundag, Ilknur; Deniz, Kiymet; Mulazimoglu, Ibrahim Ender; Erdogan, M. Selcuk; Kadioglu, Yusuf Kagan
    In this study, we tried to obtain information about the level of pollution in the region by analyzing the solid residues collected from the roadsides of Konya, which is an industrialized city of Turkey. In the study, solid powder samples were collected from Konya city in September 2014, at 4 different times by the municipal vehicles. The samples, collected from a total of 21 different regions were analyzed. Collected samples were first sifted through 250 gm sieves, then pelletized into 32 mm pellets with a wax binder. The elements in the prepared samples were determined by polarized energy-dispersive X-ray fluorescence (PEDXRF) spectrometry. Elements such as Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Sr, Zr, Ba, La, Ce and Pb were determined by PEDXRF. The reliability of the method was also tested with CRM 2126-81 standard substance. The amount of elements such as As, Cr, Ni, Co and Fe were particularly discussed in the regions close to industrial establishments, whereas the amount of Pb was discussed for the routes on the main road.
  • Küçük Resim Yok
    Öğe
    Investigation of Sensitivity Against Different Flavonoid Derivatives of Aminophenyl-Modified Glassy Carbon Sensor Electrode and Antioxidant Activities
    (Springer, 2012) Mulazimoglu, Ibrahim Ender; Mulazimoglu, Aysen Demir
    The electrochemical behaviors of 10 structurally different flavonoids (quercetin, galangin, chrysin, 3-hydroxyflavone, naringenin, luteolin, apigenin, flavone, kaempferol, and naringin) on a glassy carbon electrode were studied by cyclic voltammetry. In the current study, nitrophenyl diazonium salt has been synthesized from p-nitrophenylamine. One millimolar prepared nitrophenyl diazonium salt (in 100 mM tetrabutylammonium tetrafluoroborate) in acetonitrile was used to modify the glassy carbon electrode. Nitro groups have been reduced to amine groups in 100 mM HCl medium on the nitrophenyl-modified glassy carbon electrode surface. Although nitrophenyl-modified glassy carbon electrode surface was electro-inactive, it is activated by reducing the nitro group into amine group. And then, aminophenyl-modified glassy carbon electrode surface has been used for the determination of antioxidant activities of 10 flavonoid derivatives with cyclic voltammetry technique. The activity sequence of the investigated, structurally different, flavonoids follows the sequence: quercetin > galangin > chrysin > 3-hydroxyflavone > naringenin > luteolin > apigenin > flavone > kaempferol > naringin.
  • Küçük Resim Yok
    Öğe
    Isophtalic acid terminated graphene oxide modified glassy carbon nanosensor electrode: Cd2+ and Bi3+ analysis in tap water and milk samples
    (Taylor & Francis Inc, 2017) Albayrak, Isa; Erkal, Asli; Yavuz, Samet; Kariper, Ishak Afsin; Mulazimoglu, Ibrahim Ender; Ustundag, Zafer
    In this study, graphene oxide was derivative with 5-aminoisophtalic acid by amidization reaction. The nanomaterial in suspension was denoted as graphene oxide-isophtalic acid. The graphene oxide-isophtalic acid suspension was covered on the glassy carbon electrode surface under the infrared lamb. The graphene oxide was characterized with transmission electron microscopy and x-ray diffraction. Surface characterization of the glassy carbon/graphene oxide-isophtalic acid was performed with x-ray photoelectron spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The ultrasensitive nanoplatform for the simultaneous electrochemical square-wave anodic stripping voltammetry assay of Bi3+ and Cd2+ in aqueous solution has been developed on the glassy carbon/graphene oxide-isophtalic acid. The linearity range of Bi3+ and Cd2+ were 1.0x10(-8) - 1.0x10(-12) M (S/N = 3). The responses of species were practically unaltered with the increase of various species concentration. The detection limits of Cd2+ and Bi3+ were determined as 8.1x10(-13) M and 1.06x10(-13) M, respectively. The electrode performance was checked with tap water and commercially milk samples.
  • Küçük Resim Yok
    Öğe
    Sensitive and selective determination of paracetamol in antipyretic children's syrup with a polyglycine modified glassy carbon electrode
    (Royal Soc Chemistry, 2023) Islamoglu, Nesim; Mulazimoglu, Ibrahim Ender; Mulazimoglu, Aysen Demir
    A sensitive and selective electrochemical sensor for the determination of paracetamol (acetaminophen) is proposed based on a polyglycine-coated glassy carbon electrode. The electrochemical behavior of paracetamol was studied by cyclic voltammetry and differential pulse voltammetry. Under optimal experimental conditions, the peak oxidation current of paracetamol increases linearly in the range of 0.5-75 & mu;M. The limit of detection of paracetamol was 0.03 & mu;M and the limit of quantitation was 0.09 & mu;M. In addition, modified glassy carbon with polyglycine as the sensor was successfully used for the determination of paracetamol in antipyretic children's syrup samples, with a recovery rate of over 95.3%, showing its great application potential in drug analysis.
  • Küçük Resim Yok
    Öğe
    Voltammetric Determination of Acrylamide Using Coal Tar Pitch Modified Pencil Graphite Electrode by SWV
    (Springer, 2023) Korkmaz, Seyma; Bosnali, Wael; Mulazimoglu, Ibrahim Ender; Mulazimoglu, Aysen Demir
    The adverse effects of acrylamide (AA) on humans are becoming clear, especially after a series of related investigations reported the dependence on consuming foods prepared by exposure to high temperatures for a long-time and cancer risk. Accurate determination of AA in food samples at trace amount is considered the first step to overcome this significant problem. The determination of AA using coal tar pitch modified pencil graphite (PGE/CTP) electrode was reported. The bare PGE and PGE/CTP electrodes were characterized using microscopic imaging technique scanning electron microscopy (SEM). The electrochemical behavior of AA was studied on PGE/CTP electrode in different medium acidities (pH) of phosphate and Briton-Robinson (BR) buffer solutions by employing square wave voltammetry (SWV). Linear sweep voltammetry (LSV) technique was applied to determine the mass transfer mode of AA from bulk solution to the PGE/CTP electrode surface. The optimum conditions were using phosphate buffer solution (PBS) at pH 7.0. The detectability of AA on the surfaces of bare PGE and PGE/CTP electrodes was compared, and the suitability of PGE/CTP electrode usage was determined. The linear relationship between peak current and AA concentration was in the range of 1000.0 to 0.5 nM. The limit of detection of AA was 0.2094 nM, and the limit of quantitation was 0.6912 nM. In addition, the PGE/CTP electrode as a sensor was successfully used for the determination of AA in the instant coffee sample.