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3D Polyoxometalate-Functionalized Graphene Quantum Dots with Mono-Metallic and Bi-Metallic Nanoparticles for Application in Direct Methanol Fuel Cells
(Electrochemical Soc Inc, 2016) Colak, Alper Tolga; Eren, Tanju; Yola, Mehmet Lutfi; Besli, Erdem; Sahin, Onur; Atar, Necip
A fuel cell is an electrochemical cell that converts a source fuel into an electrical current. It generates electricity inside a cell through reactions between a fuel and an oxidant, triggered in the presence of an electrolyte. Fuel cells have been attracting more and more attention in recent decades due to high-energy demands, fossil fuel depletions, and environmental pollution throughoutworld. Afacile and cost-effective catalysts have been developed on polyoxometalate (NaPWO) functionalized graphene quantum dots (GQDs) with several mono-metallic and bi-metallic nanoparticles such as platinum nanoparticles (PtNPs), palladium nanoparticles (PdNPs) and platinum-palladium nanoparticles (Pt-PdNPs). The successful synthesis of nanomaterials and the prepared glassy carbon electrode (GCE) surfaces were confirmed by transmission electron microscope (TEM), X-ray photo electron spectroscopy (XPS), scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) method. According to TEM images, the average particle sizes of PtNPs and PdNPs were found to be approximately 20-30 nm. The Pt-PdNPs/NaPWO/GQDs also exhibited a higher peak current for methanol oxidation than those of comparable PdNPs/NaPWO/GQDs and PtNPs/NaPWO/GQDs, thus providing evidence for its higher electro-catalytic activity. (C) 2016 The Electrochemical Society. All rights reserved.
A Highly Efficient Nanomaterial with Molecular Imprinting Polymer: Carbon Nitride Nanotubes Decorated with Graphene Quantum Dots for Sensitive Electrochemical Determination of Chlorpyrifos
(Electrochemical Soc Inc, 2017) Yola, Mehmet Lutfi; Atar, Necip
Chlorpyrifos (CHL) is organophosphate insecticide and has low water solubility (1.39 mg/L). CHL is known to produce toxic effects by inhibiting the acetylcholinesterase enzyme activity. Because of this, the important health problems occur worldwide. Hence, it is important to detect the concentration of CHL at the sensitive levels in environmental waters. In this study, a novel molecular imprinted voltammetric sensor based on carbon nitride nanotubes (C3N4 NTs) decorated with graphene quantum dots (GQDs) modified glassy carbon electrode (GCE) was developed for determination of CHL. The unique C3N4 NTs@GQDs nanohybrid was synthesized by hydrothermal treatment. CHL imprinted GCE based on C3N4 NTs@GQDs nanohybrid was prepared via electropolymerization process of 100 mM pyrrole as monomer in the presence of phosphate buffer solution (PBS) (pH 7.0) containing 25 mM CHL. The prepared nanomaterials were characterized using scanning electron microscope (SEM), transmission electron microscope (TEM), raman spectroscopy, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The linearity range and the detection limit of the method were calculated as 1.0 x 10(-11)-1.0 x 10(-9) M and 2.0 x 10(-12) M, respectively. The sensor was applied to wastewater samples with good selectivity and recovery. The stability and selectivity of the voltammetric sensor were also reported. (C) 2017 The Electrochemical Society. All rights reserved.
A molecular imprinted SPR biosensor for sensitive determination of citrinin in red yeast rice
(Elsevier Sci Ltd, 2015) Atar, Necip; Eren, Tanju; Yola, Mehmet Lutfi
A novel and sensitive molecular imprinted surface plasmon resonance (SPR) biosensor was developed for selective determination of citrinin (CIT) in red yeast rice. Firstly, the gold surface of SPR chip was modified with allyl mercaptane. Then, CIT-imprinted poly(2-hydroxyethyl methacrylate-methacryloylamidoglutamic acid) (p(HEMA-MAGA)) film was generated on the gold surface modified with allyl mercaptane. The unmodified and imprinted surfaces were characterized by Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and contact angle measurements. The linearity range and the detection limit were obtained as 0.005-1.0 ng/mL and 0.0017 ng/mL, respectively. The SPR biosensor was applied to determination of CIT in red yeast rice sample. (C) 2015 Elsevier Ltd. All rights reserved.
A Molecular Imprinted Voltammetric Sensor Based on Carbon Nitride Nanotubes: Application to Determination of Melamine
(Electrochemical Soc Inc, 2016) Yola, Mehmet Lutfi; Eren, Tanju; Atar, Necip
Melamine (MEL) has high nitrogen rich content. Because of this situation, it has been illegally added to dairy products by producers to obtain a higher readout of apparent protein content. This has been a cause of serious diseases and many infants have been intoxicated because the addition of MEL into food products can cause death. In this report, a novel molecular imprinted voltammetric sensor based on carbon nitride nanotubes (C3N4 NTs) modified glassy carbon electrode (GCE) was presented for determination of MEL. The developed surfaces were characterized using scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). MEL imprinted GCE was prepared via electropolymerization process of 100 mM phenol as monomer in the presence of phosphate buffer solution (PBS) (pH 7.0) containing 25 nM MEL. The linearity range and the detection limit of the method were calculated as 1.0 x 10(-1)0 -5.0 x 10(-9) M and 1.0 x 10(-11) M, respectively. The voltammetric sensor was applied to milk samples with good selectivity and recovery. The stability and reproducibility of the voltammetric sensor were also reported. (C) 2016 The Electrochemical Society.
A novel and sensitive electrochemical DNA biosensor based on Fe@Au nanoparticles decorated graphene oxide
(Pergamon-Elsevier Science Ltd, 2014) Yola, Mehmet Lutfi; Eren, Tanju; Atar, Necip
A novel and sensitive electrochemical biosensor for selective determination of DNA was developed based on Fe@Au nanoparticles (Fe@AuNPs) involving 2-aminoethanethiol (AET) functionalized graphene oxide (GO) (Fe@AuNPs-AETGO). Firstly, 5 '-TA CCG GGT GCT CGA GCC-(CH2)(3)-SH-3 ' single-stranded probe (ss-DNA) was immobilized on Fe@AuNPs-AETGO nanocomposite to form ssDNA-Fe@AuNPs-AETGO. Square wave voltammetry (SWV) was applied to monitor the DNA hybridization by basic blue 41 (BB41) as an electrochemical indicator. The DNA immobilization and hybridization on the film were studied by cyclic voltammetry (CV), SWV and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the peak currents of BB41 were linear with the logarithm of the concentrations of complementary DNA (5 '-AT GGC CCA CGA GCT CGA-(CH2)(3)-SH-3) from 1.0 x 10(-14) to 1.0 x 10(-8) M with a detection limit of 2.0 x 10(-15) M. The biosensor also showed high selectivity to one-base, two-base and three-base mismatched DNA. Compared with the other electrochemical DNA biosensors, the proposed biosensor showed its own performance of simplicity, good stability and high sensitivity. (C) 2014 Elsevier Ltd. All rights reserved.
A Novel DNA Biosensor Based on a Pencil Graphite Electrode Modified with Polypyrrole/Functionalized Multiwalled Carbon Nanotubes for Determination of 6-Mercaptopurine Anticancer Drug
(Amer Chemical Soc, 2015) Karimi-Maleh, Hassan; Tahernejad-Javazmi, Fahimeh; Atar, Necip; Lutfi, Mehmet; Gupta, Vinod Kumar; Ensafi, Ali A.
A novel and sensitive biosensor employing immobilized DNA on a pencil graphite electrode modified with polypyrrole/functionalized multiwalled carbon nanotubes for the determination of 6-mercaptopurine (6-MP) is presented. In the first step, we modified the pencil graphite surface with polypyrrole and functionalized multiwalled carbon nanotubes (MWCNT/COOH). The developed electrode was characterized by scanning electron microscopy, atomic force microscopy, reflectionabsorption infrared spectroscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. In the other step, we used decreases in the oxidation responses of guanine and adenine as a sign of the interaction of 6-MP with salmon sperm double-stranded DNA using differential pulse voltammetry. The signal of guanine oxidation was linear with respect to the 6-MP concentration in the range of 0.2-100 mu mol L-1 with a detection limit of 0.08 mu mol L-1. The modified electrode was utilized for the determination of 6-MP in real samples.
A novel efficient photocatalyst based on TiO2 nanoparticles involved boron enrichment waste for photocatalytic degradation of atrazine
(Elsevier Science Sa, 2014) Yola, Mehmet Lutfi; Eren, Tanju; Atar, Necip
In this study, a novel photocatalyst based on TiO2 nanoparticles was synthesized by using a waste material (BEW) without any reducing agent and the photocatalyst (TiO2-BEW) was used for investigating photodegradation of atrazine. The transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction patterns (XRD) showed the formation of TiO2 nanoparticles on BEW. The BET surface area increased after intercalation of TiO2 nanoparticles into BEW. In photocatalytic degradation studies, the effect of operating variables such as initial atrazine concentration, catalyst dosage and contact time was also investigated. The photocatalysis kinetic studies showed that the removal of atrazine followed a pseudo-first-order reaction kinetic. The photocatalyst was synthesized as a simple, fast, clean, highly efficient and eco-friendly. The photocatalysis experiments show that TiO2-BEW can be used as novel photocatalyst in terms of stable, good efficiency, good reusability and lower cost. The photodegradation of atrazine by using TiO2-BEW is demonstrated as a more effective technique for the pesticide removal from aqueous solution. (C) 2014 Elsevier B.V. All rights reserved.
A novel electro analytical nanosensor based on graphene oxide/silver nanoparticles for simultaneous determination of quercetin and morin
(Pergamon-Elsevier Science Ltd, 2014) Yola, Mehmet Lutfi; Gupta, Vinod Kumar; Eren, Tanju; Sen, Arif Emre; Atar, Necip
In this report, silver nanoparticles (AgNPs) with the mean diameters of 10-30 nm were self-assembled onto the surfaces of 2-aminoethanethiol (2-AET) functionalized graphene oxide (AETGO) sheets. The graphene oxide (GO) and AgNPs-AETGO nanocomposites were characterized by a transmission electron microscope (TEM), x-ray photoelectron spectroscopy (XPS), reflection absorption infrared spectroscopy (RAIRS) and the x-ray diffraction (XRD). The simultaneous determination of quercetin (QR) and morin (MR) has been performed on glassy carbon electrode (GCE) modified with AgNPs-AETGO (AgNPs-AETGO/GCE). QR presented an oxidation step at Ea of 200 mV and reduction step at Ec of 150 mV and RT presented an oxidation step at Ea of 600 mV at AgNPs-AETGO/GCE by cyclic voltammetry (CV). The linearity ranges and the detection limits of QR and MR were 1.0 x 10-8 - 5.0 x 10-6 M and 3.3 x 10-9 M, respectively. The AgNPs-AETGO/GCE was also applied to real samples for the simultaneous determination of QR and MR. Thus the developed method can be adopted as an alternative to the published chromatographic, spectrophotometric and electroanalytical methods for simultaneous determination of QR and MR. (C) 2013 Elsevier Ltd. All rights reserved.
A novel glucose biosensor platform based on Ag@AuNPs modified graphene oxide nanocomposite and SERS application
(Academic Press Inc Elsevier Science, 2013) Gupta, Vinod Kumar; Atar, Necip; Yola, Mehmet Lutfi; Eryilmaz, Merve; Torul, Hilal; Tamer, Ugur; Boyaci, Ismail Hakki
This study represents a novel template demonstration of a glucose biosensor based on mercaptophenyl boronic acid (MBA) terminated Ag@AuNPs/graphene oxide (Ag@AuNPs-GO) nanomaterials. The nanocomposites were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) method. The TEM image shows that Ag@AuNPs in the nanocomposite is in the range of diameters of 10-20 nm. The nanocomposite was used for the determination of glucose through the complexation between boronic acid and diol groups of glucose. Thus, a novel glucose biosensor was further fabricated by immobilizing glucose oxidase (GOD) into MBA terminated Ag@AuNPs-GO nanocomposite film (MBA-Ag@AuNPs-GO). The linearity range of glucose was obtained as 2-6 mM with detection limit of 0.33 mM. The developed biosensor was also applied successfully for the determination of glucose in blood samples. The concentration value of glucose in blood samples was calculated to be 1.97 +/- 0.002 mM from measurements repeated for six times. (C) 2013 Elsevier Inc. All rights reserved.
A novel impedimetric biosensor based on graphene oxide/gold nanoplatform for detection of DNA arrays
(Elsevier Science Sa, 2013) Gupta, Vinod Kumar; Yola, Mehmet Lutfi; Qureshi, Munewar Saeed; Solak, Ali Osman; Atar, Necip; Ustundag, Zafer
A highly sensitive method for detection of DNA hybridization was developed. This method was based on the modification of glassy carbon electrode with gold nanoparticles (AuNPs) involving p-aminothiophenol (ATP) functionalized graphene oxide (GO). This GO was used as a platform for impedimetric genosensing using 5'-TA GGG CCA CTT GGA CCT-(CH2)(3)-SH-3' single-stranded probe (ss-DNA), 5'-AGG TCC AAG TGG CCC TA-3'(target DNA), 5'-SH-C-6-TAG GGC CA-3'(non-complementary-1) and 5'-SH-C-6-TGC CCG TTA CG 3-' (non-complementary-2) oligonucleotide sequences. The film exhibited excellent properties for immobilizing DNA probes and sensing DNA hybridization. The DNA immobilization and hybridization on the film were studied by cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), and found that the charge transfer resistance (R-ct) of the electrode increased with the concentration of the target DNA hybridized with the ss-DNA. The linear detectionrange was from 1.0 x 10(-13) M to 1.0 x 10(-7) M and the detection limit was 1.10 x 10(-14) M (n = 6). Compared with the other electrochemical DNA biosensors, the proposed biosensor showed its own performance of simplicity, good stability, and high sensitivity. (C) 2013 Elsevier B. V. All rights reserved.
A novel magnetic Fe@Au core-shell nanoparticles anchored graphene oxide recyclable nanocatalyst for the reduction of nitrophenol compounds
(Pergamon-Elsevier Science Ltd, 2014) Gupta, Vinod Kumar; Atar, Necip; Yola, Mehmet Lutfi; Ustundag, Zafer; Uzun, Lokman
In this study, a novel catalyst based on Fe@Au bimetallic nanoparticles involved graphene oxide was prepared and characterized by transmission electron microscope (TEM), and x-ray photoelectron spectroscopy (XPS). The nanomaterial was used in catalytic reductions of 4-nitrophenol and 2-nitrophenol in the presence of sodium borohydride. The experimental parameters such as temperature, the dosage of catalyst and the concentration of sodium borohydride were studied. The rates of catalytic reduction of the nitrophenol compounds have been found as the sequence: 4-nitrophenol>2-nitrophenol. The kinetic and thermodynamic parameters of nitrophenol compounds were determined. Activation energies were found as 2.33 kcal mol(-1) and 3.16 kcal mol(-1) for 4-nitrophenol and 2-nitrophenol, respectively. The nanomaterial was separated from the product by using a magnet and recycled after the reduction of nitrophenol compounds. The recyclable of the nanocatalyst is economically significant in industry. (C) 2013 Elsevier Ltd. All rights reserved.
A novel molecular imprinted nanosensor based quartz crystal microbalance for determination of kaempferol
(Elsevier Science Sa, 2014) Gupta, Vinod Kumar; Yola, Mehmet Lutfi; Atar, Necip
The molecular imprinting technique relies on the molecular recognition. It is a kind of polymerization which is formed around the target molecule. Hence this technique forms specific cavities in the cross-linked polymeric matrices. In this report, we developed quartz crystal microbalance (QCM) nanosensor for the real-time detection of kaempferol (KAE). Firstly, the modification of gold surface of QCM chip was carried out by self-assembling monolayer formation of allyl mercaptane to introduce polymerizable double bonds on the chip surface. Then, KAE imprinted poly(2-hydroxyethyl methacrylate-methacryloylamidoaspartic acid) [p(HEMA-MAAsp)] film was generated on the gold surface. The non-modified and KAE-imprinted p(HEMA-MAAsp) surfaces were characterized by using atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy and ellipsometry. The linearity range and the detection limit were obtained as 2.0 x 10(-10) to 1.5 x 10(-9) M and 6.0 x 10(-11) M, respectively. The developed method was applied to real samples such as orange and apple juices for the determination of KAE in the presence of quercetin (QR), myricetin (MYR) and apigenin (API). In addition, isotherm models were applied to data to explain adsorption process. (C) 2013 Elsevier B. V. All rights reserved.
A novel sensitive Cu(II) and Cd(II) nanosensor platform: Graphene oxide terminated p-aminophenyl modified glassy carbon surface
(Pergamon-Elsevier Science Ltd, 2013) Gupta, Vinod Kumar; Yola, Mehmet Lutfi; Atar, Necip; Ustundag, Zafer; Solak, Ali Osman
Graphene oxide (GO) based glassy carbon (GC) electrode has been prepared. Firstly, p-nitrophenyl (NP) modified GC (NP/GC) electrode was prepared via the electrochemical reduction of its tetraflouroborate diazonium salt. After the formation of NP/GC electrode, the negative potential was applied to NP/GC electrode to reduce the nitro groups to amine. p-Aminophenyl (AP) modified GC (AP/GC) electrode was immersed into a graphene oxide solution containing 1-ethyl-3(3-(dimethlyamino)propyl)-carbodiimide. Hence, we constructed GO terminated AP modified GC (GO/AP/GC) electrode. NP/GC, AP/GC and GO/AP/GC electrodes were characterized sequentially using cyclic voltammetry (CV) in the presence of 1.0 mM of potassium ferricyanide in 0.1 M KCl. In addition, GO and GO/AP/GC surfaces were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The GO/AP/GC electrode was used for the analysis of Cd(II) and Cu(II) ions by adsorptive stripping voltammetry. The linearity range and the detection limit of Cd(II) and Cu(II) ions were 1.0 x 10(-11)-5.0 x 10(-10) M and 3.3 x 10(-12) M (SIN=3), respectively. (C) 2013 Elsevier Ltd. All rights reserved.
A novel voltammetric sensor based on gold nanoparticles involved in p-aminothiophenol functionalized multi-walled carbon nanotubes: Application to the simultaneous determination of quercetin and rutin
(Pergamon-Elsevier Science Ltd, 2014) Yola, Mehmet Lutfi; Atar, Necip
Carbon nanotubes are expected to play a significant role in the design and manufacture of many nano-material devices in the future. Carbon nanotubes exhibit many unique properties which generate strong interests in studying their applications. In addition, certain properties of gold nanoparticles (e.g., conductivity, catalytic and photocatalytic activity) suggest that gold-nanoparticle-functionalized carbon nanotubes may prove applicable in future fabrication of nanodevices. In this study, gold nanoparticles (AuNPs) with the mean diameters of 20-25 nm were self-assembled onto the surfaces of p-aminothiophenol functionalized multi-walled carbon nanotubes (p-MWCNs) sheets. The p-MWCNs and AuNPs/p-MWCNs nanocomposites were characterized by reflection-absorption infrared spectroscopy (RAIRS), transmission electron microscope (TEM), x-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and x-ray diffraction (XRD) method. The simultaneous determination of quercetin (QR) and rutin (RT) was performed by square wave voltammetry (SWV) on glassy carbon electrode (GCE) modified with AuNPs/p-MWCNs nanocomposite (AuNPs/p-MWCNs-GCE). QR presented two oxidation steps at E-a1 of 270 mV and E-a2 of 450 mV and RT presented only one oxidation step at E-a of 360 mV at AuNPs/p-MWCNs-GCE. The linearity ranges and the detection limits of QR and RT were 1.0 x 10(-9) - 5.0 x 10(-8) M and 33 x 10(-10). The application of the prepared nanocomposite to the analysis of real sample was also investigated. (C) 2013 Elsevier Ltd. All rights reserved.
A novel voltammetric sensor based on p-aminothiophenol functionalized graphene oxide/gold nanoparticles for determining quercetin in the presence of ascorbic acid
(Elsevier Science Sa, 2013) Yola, Mehmet Lutfi; Atar, Necip; Ustundag, Zafer; Solak, Ali Osman
In this study, gold nanoparticles (AuNPs) with the diameters of maximum 25 nm were self-assembled onto the surfaces of p-aminothiophenol functionalized graphene oxide (ATPGO) sheets simply by mixing their aqueous dispersions. The prepared graphene oxide (GO), ATPGO and AuNPs-ATPGO composites were characterized by a transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), reflection-absorption infrared spectroscopy (RAIRS), the X-ray diffraction (XRD) method and Raman spectroscopy. The electrochemical determination of quercetin (QR) has been studied using square wave voltammetry (SWV) on glassy, carbon electrode (GCE) modified with AuNPs-ATPGO composite (AuNPs-ATPGO/GCE). QR gave rise to a single oxidation peak in the potential interval from 200 to 600 mV in 0.1 M acetate buffer (pH 5.5). The well-defined peaks were observed at the optimized instrumental parameters for SWV such as frequency, amplitude and potential increments. The developed method was validated according to the ICH guideline and found to be linear, sensitive, specific, precise and accurate. The linearity range of QR was 1.0 x 10(-12)-1.0 x 10(-11) M with the detection limit (S/N = 3) of 3.0 x 10(-13) M under optimum conditions. The validated method was applied successfully for the determination of QR in pharmaceutical preparations. (C) 2013 Elsevier B.V. All rights reserved.
A Review: Molecularly Imprinted Electrochemical Sensors for Determination of Biomolecules/Drug
(Bentham Science Publ Ltd, 2017) Yola, Mehmet Lutfi; Atar, Necip
The interdisciplinary field of materials science involves the discovery and design of new materials. Because of this, materials science has effective interest in the fabrication of biosensors/nanosensors. In this review, we have focused on molecular imprinted electrochemical sensors based nanomaterials such as graphene oxide/carbon nanotubes molecular imprinting has been very effective method to achieve high selectivity and sensitivity for the fabrication of sensors. It is based on the formation of three-dimensional nano-cavities in crosslinking polymer matrix, where the functional and crosslinking monomers are copolymerised in the presence of target molecule (imprint molecule), which acts as a molecular template. In an imprinted polymer, the chemically active moieties of the target molecules are held in position by the highly crosslinked polymeric networks. In addition, the novel nanomaterials such as graphene/carbon nanotubes have many applications in sensor technology. The review presents the recent developments related to molecularly imprinted electrochemical sensors based carbon nanomaterials.
A sensitive molecular imprinted electrochemical sensor based on gold nanoparticles decorated graphene oxide: Application to selective determination of tyrosine in milk
(Elsevier Science Sa, 2015) Yola, Mehmet Lutfi; Eren, Tanju; Atar, Necip
In present study, a sensitive imprinted electrochemical sensor based on cubic gold nanoparticles (cAuNPs) involved in 2-aminoethanethiol (2-AET) functionalized graphene oxide (GO) modified glassy carbon(GC) electrode was developed for determination of tyrosine (Tyr). The prepared nanomaterials were characterized by using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and reflection-absorption infrared spectroscopy (RAIRS). Tyr imprinted film was constructed by cyclic voltammetry (CV) for 20 cycles in the presence of 80 mM phenol in phosphate buffer solution (pH 7.0) containing 20 mM Tyr. The imprinted electrochemical sensor was validated according to the ICH guideline and found to be linear, sensitive, precise and accurate. The linearity range and the detection limit were obtained as 1.0 x 10(-9) to 2.0 x 10(-8) M and 1.5 x 10(-10) M, respectively. The developed imprinted sensor was successfully applied to milk samples. In addition, the stability and reproducibility of the prepared molecular imprinted electrode were investigated. The excellent long-term stability and reproducibility of the prepared Tyr imprinted electrodes make them attractive in electrochemical sensors. (C) 2014 Elsevier B.V. All rights reserved.
A sensitive molecular imprinted surface plasmon resonance nanosensor for selective determination of trace triclosan in wastewater
(Elsevier Science Sa, 2015) Atar, Necip; Eren, Tanju; Yola, Mehmet Lutfi; Wang, Shaobin
Triclosan (TCS) has been widely used as an antibacterial and antifungal agent in household cleaning and personal care products. The widespread use of TCS in the cleaning products poses a potential risk to the ecological system and human health due to its release into sediments, wastewater and ground water resources causing chronicle toxicity to aquatic organisms. However, no simple method is available for its detection and quantitative determination in aqueous solution. A novel molecular imprinted surface plasmon resonance (SPR) chemical sensor was developed for sensitive and selective detection of triclosan (TCS) in wastewater, using allylmercaptane modified gold SPR chip and imprinted poly( 2-hydroxyethyl methacrylate-methacryloylamidoglutamic acid) [p(HEMAGA)] nanofilm. The unmodified and imprinted surfaces of the SPR chip were characterized by Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and contact angle measurements. The developed sensor was validated according to the ICH guideline (International Conference on Harmonisation). The linearity range and detection limit of TCS were obtained as 0.05-1.0 ng/mL and 0.017 ng/mL, respectively. The developed molecular imprinted nanosensor was successfully applied to wastewater samples for the determination of TCS and exhibited excellent performance. (C) 2015 Elsevier By. All rights reserved.
A sensitive molecularly imprinted polymer based quartz crystal microbalance nanosensor for selective determination of lovastatin in red yeast rice
(Elsevier Sci Ltd, 2015) Eren, Tanju; Atar, Necip; Yola, Mehmet Lutfi; Karimi-Maleh, Hassan
Lovastatin (LOV) is a statin, used to lower cholesterol which has been found as a hypolipidemic agent in commercial red yeast rice. In present study, a sensitive molecular imprinted quartz crystal microbalance (QCM) sensor was prepared by fabricating a self-assembling monolayer formation of allylmercaptane on QCM chip surface for selective determination of lovastatin (LOV) in red yeast rice. To prepare molecular imprinted quartz crystal microbalance (QCM) nanosensor, LOV imprinted poly(2-hydroxyethyl methacrylate-methacryloylamidoaspartic acid) [p(HEMA-MAAsp)] nanofilm was attached on the modified gold surface of QCM chip. The non-modified and improved surfaces were characterized by using contact angle, atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. The imprinted QCM sensor was validated according to the ICH guideline (International Conference on Harmonisation). The linearity range was obtained as 0.10-1.25 nM. The detection limit of the prepared material was calculated as 0.030 nM. The developed QCM nanosensor was successfully used to examine red yeast rice. Furthermore, the stability and repeatability of the prepared QCM nanosensor were studied. The spectacular long-term stability and repeatability of the prepared LOV-imprinted QCM nanosensor make them intriguing for use in QCM sensors. (C) 2015 Elsevier Ltd. All rights reserved.
A sensitive voltammetric sensor for determination of Cd(II) in human plasma
(Elsevier, 2014) Yola, Mehmet Lutfi; Eren, Tanju; Ilkimen, Halil; Atar, Necip; Yenikaya, Cengiz
The development of electrochemical sensors via surface modification has attracted considerable attention as a low-cost method to the sensitive detection of a variety of analytes. In addition, the surface modification of electrodes has been directed toward several goals, often involving electrode kinetics and chemical selectivity. In this study, we performed the electrochemical modification of glassy carbon (GC) electrode with 2-thiolbenzimidazole (2-TBI). The developed electrode was characterized by the reflection-absorption infrared spectroscopy (RAIRS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). According to the RAIRS results, the binding type of the 2-TBI to glassy carbon electrode was through the etheric linkage. The working range of the developed electrode was also studied. In addition, the developed electrode was applied to human plasma samples for the determination of Cd(II). The linearity range of Cd(II) was obtained as 1.0 x 10(-11)-2.5 x 10(-10) M with the detection limit (S/N = 3) of 2.40 x 10(-12) M. (C) 2014 Elsevier B.V. All rights reserved.

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