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Öğe 1,10-Phenanthroline-5,6-dione and 9,10-phenanthrenequinone as redox mediators for amperometric glucose biosensors(SPRINGER, 2014) Zor, Erhan; Oztekin, Yasemin; Mikoliunaite, Lina; Voronovic, Jaroslav; Ramanaviciene, Almira; Anusevicius, Zilvinas; Bingol, HalukIn this study, two ortho-quinoidal compounds, 1,10-phenanthroline-5,6-dione (PD) and 9,10-phenanthrenequinone (PQ), were examined as electron transfer mediators suitable for amperometric glucose biosensors. The dependences of the electrochemical responses of PD- and PQ-based amperometric glucose biosensors on varied concentrations of glucose were investigated under aerobic and anaerobic conditions. The PD-modified graphite rod (GR) electrode revealed a current response seven times higher than that of the PQ-modified GR electrode. The reactivity indices of ortho-quinoidals assessed by means of B3LYP functional method applying 6-311G(D) basis set showed that the electron-accepting potency for PD was markedly higher as compared with that of PQ. Compared to PQ, considerably higher reactivity of PD has been defined in the reactions with NADP(+)-ferredoxin reductase (FNR, EC 1.18.1.2) as a model single-electron transfer FAD-dependent enzyme, which provided an additional evidence for PD as a more efficient mediator compared to PQ. This study illustrates that PD can be applied as a redox mediator for glucose oxidase and it could be more suitable for a reagent-less biosensor design than PQ.Öğe Amperometric Glucose Biosensor Based on Glucose Oxidase, 1,10-Phenanthroline-5,6-dione and Carbon Nanotubes(ELECTROCHEMICAL SOC INC, 2014) Zor, Erhan; Öztekin, Yasemin; Ramanaviciene, Almira; Anusevicius, Zilvinas; Bingöl, Haluk; Barkauskas, Jurgis; Ersöz, MustafaA biosensor for glucose determination was fabricated by the immobilization of glucose oxidase (GOx) on carbon nanotubes (CNTs) and/or 1,10-phenanthroline-5,6-dione (PD) modified graphite rod electrodes (GOx/PD/CNTs/GR) and its amperometric response toward glucose was investigated under aerobic and anaerobic conditions. The sensitivity of the GOx/PD/CNTs/GR electrode was found to be higher compared to that of a PD-modified GR electrode without CNTs (GOx/PD/GR), implying that CNTs play an important role in the facilitation of electron transfer between the redox active site of GOx and the electrode surface. The GOx/PD/CNTs/GR biosensor exhibited a linear dependency on substrate concentration in a range from 0.0 until 50.0 mM of glucose with oxygen present and from 0.0 until 62.5 mM of glucose in the absence of oxygen. With oxygen present, the limit of detection (LOD) values were determined to be 5.4 and 8.0 mM, and the limit of quantitation values (LOQ) were calculated as 16.2 and 24 mM for GOx/PD/GR and GOx/PD/CNTs/GR, respectively. In the absence of oxygen, the LOD values were calculated as 4.2 and 10.7 mM, and the LOQ values were calculated as 12.6 and 32.1 mM for GOx/PD/GR and GOx/PD/CNTs/GR, respectively. When examining the interference effect of uric acid for GOx/PD/GR and GOx/PD/CNTs/GR electrodes, no significant changes in the amperometric response of the modified electrodes were observed up to 100.0 mM of uric acid. (C) 2014 The Electrochemical Society. All rights reserved.Öğe Discriminative sensing of DOPA enantiomers by cyclodextrin anchored graphene nanohybrids(ELSEVIER SCIENCE BV, 2017) Ateş, Salih; Zor, Erhan; Akın, İlker; Bingöl, Haluk; Alpaydın, Sabri; Akgemci, Emine GülerDiscriminative sensing of chiral species with a convenient and robust system is a challenge in chemistry, pharmaceutics and particularly in biomedical science. Advanced nanohybrid materials for discrimination of these biologically active molecules can be developed by combination of individual obvious advantages of different molecular scaffolds. Herein, we report on the comparison of the performance of cyclodextrin functionalized graphene derivatives (x-CD/rGO, x: alpha-, beta-, gamma-) for discrimination of DOPA enantiomers. Within this respect, electrochemical measurements were conducted and the experimental results were compared to molecular docking method. Thanks to cavity size of g-CD and the unique properties of graphene, rGO/gamma-CD nanohybrid is capable of selective recognition of DOPA enantiomers. Limit of detection (LOD) value and sensitivity were determined as 15.9 mu M and 0.2525 mu A mu M-1 for D- DOPA, and 14.9 mu M and 0.6894 mu A mu M-1 for L-DOPA. (C) 2017 Elsevier B.V. All rights reserved.Öğe An electrochemical and computational study for discrimination of D- and L-cystine by reduced graphene oxide/beta-cyclodextrin(ROYAL SOC CHEMISTRY, 2015) Zor, Erhan; Bingol, Haluk; Ramanaviciene, Almira; Ramanavicius, Arunas; Ersoz, MustafaHere, we report a novel enantioselective electrochemical biosensor for the discrimination of cystine enantiomers (D- and L-cystine) using a chiral interface for the specific recognition of D- and L-cystine. The biosensor is based on reduced graphene oxide modified by beta-cyclodextrin (rGO/beta-CD) at the GCE surface. During the preparation of rGO/beta-CD/GCE, the modified electrode surfaces were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The electrochemical behaviours of the D- and L-cystine were investigated using the rGO/beta-CD/GCE by CV and compared to bare GCE. A clear separation between the oxidation peak potentials of D- and L-cystine was observed at 1.32 and 1.42 V, respectively. The electrochemical discrimination performance of the fabricated chiral sensor was also examined by differential pulse voltammetry (DPV) in a mixed solution of D- and L-cystine. In addition, the DPV technique was used for the determination of D- and L-cystine at low concentration values in the range of 1.0-10.0 mM. To investigate the amperometric response of rGO/beta-CD/GCE towards D- and L-cystine, the chronoamperometry technique was used in the concentration range of 10.0-100.0 mu M. The interactions of the enantiomers with rGO/beta-CD were modelled by molecular docking using AutoDock Vina, and the interaction energies were predicted to be -4.8 and -5.3 kcal mol(-1) for D- and L-cystine, respectively. The corresponding values of binding constants were calculated to be 3.32 x 10(3) and 7.71 x 10(3) M-1, respectively. The experimental and molecular docking results indicate that the rGO/beta-CD/GCE has a different affinity for each enantiomer.Öğe An electrochemical biosensor based on human serum albumin/graphene oxide/3-aminopropyltriethoxysilane modified ITO electrode for the enantioselective discrimination of D- and L-tryptophan(ELSEVIER ADVANCED TECHNOLOGY, 2013) Zor, Erhan; Patir, Imren Hatay; Bingol, Haluk; Ersoz, MustafaA new electrochemical biosensor based on the human serum albumin/graphene oxide/3-aminopropyl-triethoxysilane modified indium tin oxide electrode (ITO/APTES/GO/HSA) has been developed for the discrimination of tryptophan (Trp) enantiomers. The electrode has been characterized by scanning electron microscopy (SEM) and electrochemical techniques. The electrochemical behaviors of the enantiomeric pairs (D- and L-Trp) at the ITO/APTES/GO/HSA electrode have been investigated by cyclic voltammetry in the concentration range of 0.10-1.0 mM. A clear separation between the oxidation peak potentials of D- and L-Trp, at 0.86 and 1.26 V, respectively, has suggested that the ITO/APTES/GO/HSA electrode can be used as an electrochemical biosensor for the discrimination of Trp enantiomers. In order to find the percentage of an enantiomeric form of tryptophan in a mixture, the ITO/APTES/GO/HSA electrode is used for the simultaneous detection of D- and L-Trp which showed that the percentage of one enantiomeric form can be easily measured in the presence of the other. (c) 2012 Elsevier B.V. All rights reserved.Öğe Evaluation of 1,10-phenanthroline-5,6-dione as redox mediator for glucose oxidase(MAIK NAUKA/INTERPERIODICA/SPRINGER, 2016) Zor, Erhan; Oztekin, Yasemin; Ramanaviciene, Almira; Anusevicius, Zilvinas; Voronovic, Jaroslav; Bingol, Haluk; Barauskas-Memenas, DanaA low-cost and simply fabricated amperometric glucose biosensor based on glucose oxidase (GOx) and 1,10-phenanthroline-5,6-dione (PD) modified graphite rod electrode was developed. The electrode exhibited good electrocatalytic activity with a well-defined hyperbolic dependence of amperometric signal upon glucose concentration in the presence and in the absence of oxygen. The electrode showed a good reproducibility and repeatability with relative standard deviation of less than 3 and 5%, respectively. The interaction of GOx with PD mediator was confirmed by means of UV?Vis absorbance spectroscopy.Öğe Graphene Quantum Dots-based Photoluminescent Sensor: A Multifunctional Composite for Pesticide Detection(AMER CHEMICAL SOC, 2015) Zor, Erhan; Morales-Narvaez, Eden; Zamora-Galvez, Alejandro; Bingol, Haluk; Ersoz, Mustafa; Merkoci, ArbenDue to their size and difficulty to obtain, cost/effective biological or synthetic receptors (e.g., antibodies or aptamers, respectively), organic toxic compounds (e.g., less than 1 kDa) are generally challenging to detect using simple platforms such as biosensors. This study reports on the synthesis and characterization of a novel multifunctional composite material, magnetic silica beads/graphene quantum dots/molecularly imprinted polypyrrole (mSGP). mSGP is engineered to specifically and effectively capture and signal small molecules due to the synergy among chemical, magnetic, and optical properties combined with molecular imprinting of tributyltin (291 Da), a hazardous compound, selected as a model analyte. Magnetic and selective properties of the mSGP composite can be exploited to capture and preconcentrate the analyte onto its surface, and its photoluminescent graphene quantum dots, which are quenched upon analyte recognition, are used to interrogate the presence of the contaminant. This multifunctional material enables a rapid, simple and sensitive platform for small molecule detection, even in complex mediums such as seawater, without any sample treatment.Öğe Graphene-based hybrid for enantioselective sensing applications(ELSEVIER ADVANCED TECHNOLOGY, 2017) Zor, Erhan; Morales-Narvaez, Eden; Alpaydın, Sabri; Bingöl, Haluk; Ersöz, Mustafa; Merkoci, ArbenChirality is a major field of research of chemical biology and is essential in pharmacology. Accordingly, approaches for distinguishing between different chiral forms of a compound are of great interest. We report on an efficient and generic enantioselective sensor that is achieved by coupling reduced graphene oxide with gamma-cyclodextrin (rGO/gamma-CD). The enantioselective sensing capability of the resulting structure was operated in both electrical and optical mode for of tryptophan enantiomers (D-/L-Trp). In this sense, voltammetric and photoluminescence measurements were conducted and the experimental results were compared to molecular docking method. We gain insight into the occurring recognition mechanism with selectivity toward D- and L-Trp as shown in voltammetric, photoluminescence and molecular docking responses. As an enantioselective solid phase on an electrochemical transducer, thanks to the different dimensional interaction of enantiomers with hybrid material, a discrepancy occurs in the Gibbs free energy leading to a difference in oxidation peak potential as observed in electrochemical measurements. The optical sensing principle is based on the energy transfer phenomenon that occurs between photo excited D-/L-Trp enantiomers and rGO/gamma-CD giving rise to an enantioselective photoluminescence quenching due to the tendency of chiral enantiomers to form complexes with gamma-CD in different molecular orientations as demonstrated by molecular docking studies. The approach, which is the first demonstration of applicability of molecular docking to show both enantioselective electrochemical and photoluminescence quenching capabilities of a graphene-related hybrid material, is truly new and may have broad interest in combination of experimental and computational methods for enantiosensing of chiral molecules. (C) 2016 Elsevier B.V. All rights reserved.Öğe Green synthesis of reduced graphene oxide/nanopolypyrrole composite: characterization and H2O2 determination in urine(ROYAL SOC CHEMISTRY, 2014) Zor, Erhan; Saglam, Muhammed Esad; Akin, Ilker; Saf, Ahmet Ozgur; Bingol, Haluk; Ersoz, MustafaHere we report on a novel, simple and eco-friendly approach for the fabrication of a reduced Graphene Oxide/nanopolypyrrole (rGO/nPPy) composite material and its electrochemical performance for detection of hydrogen peroxide on a glassy carbon electrode. The characterization of the as-prepared rGO/nPPy composite was investigated by Fourier transform infrared spectroscopy, thermogravimetric analysis, ultraviolet-visible spectroscopy, scanning electron microscopy, contact angle measurement, cyclic voltammetry and electrochemical impedance spectroscopy. Cyclic voltammetry, differential pulse voltammetry and chronoamperometry techniques were used to investigate and optimize the performance of the developed electrochemical biosensor. The proposed biosensor showed excellent analytical response towards the quantification of H2O2 at pH 7.40. Under the optimized conditions, the biosensor shows a linear response range from 1.0 x 10(-7) to 4.0 x 10(-6) M concentrations of H2O2. The limit of detection was determined to be 34 nM. Reproducibility, sensitivity, stability and anti-interference capability of the fabricated biosensor for the detection of H2O2 were examined. The biological relevance of the developed electrochemical biosensor was further studied by the determination of H2O2 in urine samples. The real sample analysis of H2O2 was achieved before and after drinking coffee in urine samples. The successful and sensitive determination of H2O2 urine samples indicates that the proposed electrochemical biosensor can be applied to the quantification analysis of H2O2 in real samples.Öğe Green Synthesis of Reduced Graphene Oxide/Polyaniline Composite and Its Application for Salt Rejection by Polysulfone-Based Composite Membranes(AMER CHEMICAL SOC, 2014) Akin, Ilker; Zor, Erhan; Bingol, Haluk; Ersoz, MustafaIn this study, a novel, simple, and eco-friendly enzymatic-reaction-based approach to produce reduced graphene oxide/polyaniline (rGO/PANI) composite material was proposed. Glucose oxidase (GOx) was used as an effective catalyst producing hydrogen peroxide, in the presence of glucose, for the oxidative polymerization of aniline under ambient conditions. The prepared rGO/PANI composite was dispersed in polysulfone (PSf), and the mixed membranes were prepared by the phase inversion polymerization method. The morphology of membranes was investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), and contact angle (CA) techniques. The performance of membranes was studied in terms of salt rejection and pure water flux. The incorporation of rGO into the membrane matrix led to hydrophobic membrane surface with the enhanced macro-voids. On the contrary, the contact angle data revealed that the rGO/PANI-incorporated membrane surface is partly hydrophilic due to the PANI fibers in membrane, whereas SEM images showed the enhanced macro-voids. Membranes exhibited an improved salt rejection after rGO/PANI doping. The rGO/PANI-modified membrane loading exhibited a maximum of 82% NaCl rejection at an applied pressure of 10 bar. In addition, the results showed that the PSf-rGO/PANI composite membrane had the highest mean porosity and water flux.Öğe A Novel Benzothiazole Based Azocalix[4]arene as a Highly Selective Chromogenic Chemosensor for Hg2+ İon: A Rapid Test Application in Aqueous Environment(Elsevier Science Bv, 2010) Bingöl, Haluk; Kocabaş, Erdal; Zor, Erhan; Coşkun, AhmetA novel calix[4]arene derivative containing benzothiazole azo groups at the upper rim was synthesized as chromogenic chemosensor, and its binding and sensing properties with heavy metal ions (Pb2+, Hg2+, Ni2+, Cd2+, Cu2+, Zn2+, Co2+, Fe2+, Mn2+, Cr3+, Ag+) were investigated by UV-vis spectroscopy and voltammetric techniques. The results of spectroscopic and voltammetric experiments showed that the chromogenic chemosensor has high selectivity towards Hg2+ ion over the other heavy metal ions. Moreover, it was shown that the interaction between Hg2+ and the chromogenic chemosensor occurs by means of the benzothiazole azo groups at the upper rim by using differential pulse voltammetry. The stoichiometric ratio and the association constant were determined as 1:1 and (6.1 +/- 0.3) x 10(5) L mol(-1) for the complex between Hg2+ and the ionophore. Furthermore, we prepared a rapid test kit for early detection of Hg2+ in aqueous environment in the concentration range of 1 x 10(-4) to 1 x 10(-2) M.Öğe Photo luminescent Lateral-Flow Immunoassay Revealed by Graphene Oxide: Highly Sensitive Paper-Based Pathogen Detection(AMER CHEMICAL SOC, 2015) Morales-Narvaez, Eden; Naghdi, Tina; Zor, Erhan; Merkoci, ArbenA paper-based lateral flow immunoassay for pathogen detection that avoids the use of secondary antibodies and is revealed by the photoluminescence quenching ability of graphene oxide is reported., Escherichia coli has been selected as a model pathogen. The proposed device is able to display a highly specific and sensitive performance with a limit of detection of 10 CFU mL(-1) in standard buffer and 100 CFU mL(-1) in bottled water and milk. This low-cost disposable and easy-to-use device will prove valuable for portable and automated diagnostics applications.Öğe Preparation of a novel PSf membrane containing rGO/PTh and its physical properties and membrane performance(ROYAL SOC CHEMISTRY, 2015) Saf, Ahmet Ozgur; Akin, Ilker; Zor, Erhan; Bingol, HalukRecent advances in the fabrication of nanostructures such as graphene-related materials have received a lot of attention in membrane technology for the future of water supplies. Herein, we report the synthesis of a reduced graphene oxide/polythiophene (rGO/PTh) composite material using an in situ enzymatic polymerization reaction, which is an eco-friendly and a simple way to construct a nanocomposite material. Polysulfone (PSf) mixed matrix composite membranes containing rGO and rGO/PTh were prepared via a phase inversion method. The morphology of the membranes was evaluated by various characterization methods, including SEM, AFM, contact angle and porosity measurements. The performance and antifouling properties of the membranes were examined in detail. The PSf-rGO/PTh membrane showed a significant improvement in water flux permeability due to the enhancement of hydrophilicity and porosity. Moreover, the PSf-rGO/PTh membrane exhibited an approximately 10 times higher improved water flux than that of the rGO membrane as the pressure was increased. The fouling resistance ratio (FRR) and antifouling properties of the membranes were tested using two different protein solutions: bovine serum albumin (BSA) and cytochrome c (Ctc). The antifouling and FRR properties of the PSf-rGO/PTh membrane decreased due to not only the interactions between the functional groups on the membrane surface and fouling materials, but also the morphological properties of the membrane.Öğe A reduced graphene oxide/alpha-cyclodextrin hybrid for the detection of methionine: electrochemical, fluorometric and computational studies(ROYAL SOC CHEMISTRY, 2014) Zor, Erhan; Sağlam, Muhammed Esad; Alpaydın, Sabri; Bingöl, HalukWe report on fluorometric and voltammetric detection of L-methionine (Met) based on host-guest interactions between Met and reduced graphene oxide/alpha-cyclodextrin (rGO/alpha-CD) hybrid materials. For voltammetric measurements, rGO/alpha-CD was used as an electrode modification material and successful detection of Met was achieved. Also, rGO/alpha-CD was used as a fluorescence quencher (turn off) for luminol which was employed as a fluorescent probe. The addition of Met into the same solution gave rise to fluorescence enhancement (turn on) after the host-guest recognition between Met and rGO/alpha-CD which caused the release of luminol. Interactions of luminol and Met with rGO/alpha-CD were modeled by molecular docking using AutoDock Vina and the interaction energies were predicted to be -4.3 and -4.4 kcal mol(-1), respectively. The proposed biosensor is considered to be a promising model for the detection of Met.Öğe Spectrophotometric and electrochemical behavior of a novel azocalix[4]arene derivative as a highly selective chromogenic chemosensor for Cr+3(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Bingol, Haluk; Kocabas, Erdal; Zor, Erhan; Coskun, AhmetIn this study, a novel azocalix[4]arene derivative, 5,11,17-tris[(1-naphtyl)azo]-25,26,27,28-tetrahydroxycalix[4]arene (NAC4) bearing napthyl groups on the upper rim was synthesized. Its complexation behavior for alkali, alkaline-earth and various heavy metal ions (Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Pb2+, Hg2+, Ni2+, Cd2+, Cu2+, Zn2+, Co2+, Fe2+, Cr3+, Ag+) was investigated by spectroscopic and voltammetric methods. This chemosensor exhibits decreased absorbance in the presence of Hg2+ and a unique absorbance quenching effect only for Cr3+. In addition, a new absorption band centered at 565 nm with the formation of the 1:1 host-guest complex (Cr3+-NAC4) was observed in the case of Cr3+, leading to an obvious color change from light orange to dark lilac. In voltammetric experiments, Cr3+ ions decreased voltammetric peaks of NAC4, whereas no significant changes occurred in the presence of the other metal ions. The Benesi-Hildebrand method was used to determine a logarithmic value of 3.76 for the association constant of the complex between Cr3+ and NAC4. (C) 2010 Elsevier Ltd. All rights reserved.Öğe Spectrophotometric and voltammetric characterization of a novel selective electroactive chemosensor for Mg2+(VERSITA, 2013) Zor, Erhan; Saf, Ahmet Ozgur; Bingol, HalukA novel azocalix[4]arene derivative, 5,11,17,23-tetrakis[(acetophenone)azo]-25,26,27,28-tetrahydroxycalix[4]arene (APC4), containing acetophenone azo groups at the upper rim was synthesized as a chemosensor. Its binding and sensing properties with alkali and alkaline earth metal ions (Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+) were investigated by UV-vis spectrophotometric and voltammetric techniques. The stoichiometric ratio and the association constant were determined spectrophotometrically as 1:1 and (1.94 +/- 0.31)x10(5) L mol(-1) for the complex between Mg2+ and the chemosensor, respectively. Moreover, it was shown that the interaction between Mg2+ and the APC4 occurred by means of the phenol groups at the lower rim by voltammetric methods. The results of spectrophotometric and voltammetric experiments showed that the chromogenic chemosensor has high selectivity towards Mg2+ among the other used metal ions, especially the interfering Ca2+ ion.Öğe Voltammetric characterization of selective potassium ion transfer across micro-water/1,2-dichloroethane interface facilitated by a novel calix[4]arene derivative(PERGAMON-ELSEVIER SCIENCE LTD, 2011) Durmaz, Müge; Zor, Erhan; Kocabaş, Erdal; Bingöl, Haluk; Akgemci, Emine GülerIn this study, transfer reactions of alkali and alkaline-earth metal ions across a micro-water/1,2-dichloroethane (1,2-DCE) interface facilitated by a novel calix[4]arene derivative, 5,11,17,23-tetra-tert-butyl-25,27-bis(2'amino-methylpyridine)-26,28-dihydroxy calix[4]arene (APHC4), were investigated by cyclic and differential pulse voltammetry techniques. Well-defined voltammetric behavior was obtained only for K(+) ion among the used metal ions. The electrochemical data were used to determine the stoichiometry and the appropriate association constant of the occurring complex between K(+) ion and APHC4. The obtained steady-state voltammograms indicated that the facilitated transfer process occurs with a TIC/TID mechanism according to 1:1 stoichiometry. The logarithm of the association constant (log beta(0)(1)) of K(APHC4)(+) complex in the DCE phase was calculated to be 6.32. Also, the availability of the facilitated transfer for the design of an amperometric screening sensor for K(+) ion was evaluated in the range of 50-500 mu mol dm(-3). (C) 2011 Elsevier Ltd. All rights reserved.Öğe Voltammetric discrimination of mandelic acid enantiomers(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2014) Zor, Erhan; Saf, Ahmet O.; Bingol, Haluk; Ersoz, MustafaWe report a novel electrochemical biosensor for direct discrimination of D- and L-mandelic acid (D- and L-MA) in aqueous medium. The glassy carbon electrode (GCE) surface was modified with reduced graphene oxide (rGO) and gamma-globulin (GLOB). Electrochemical characterization of the modified electrodes was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The modified electrode surfaces were also characterized by scanning electron microscopy. Electrochemical response of the prepared electrode (GCE/rGO/GLOB) for discrimination of D- and L-MA enantiomers was investigated by cyclic voltammetry and was compared with bare GCE in the concentration range of 2 to 10 mM. Whereas the bare GCE showed no electrochemical response for the MA enantiomers, the GCE/rGO/GLOB electrode exhibited direct and selective discrimination with different oxidation potential values of 1.47 and 1.71 V and weak reduction peaks at potential values of -1.37 and -1.48 V, respectively. In addition, electrochemical performance of the modified electrode was investigated in mixed solution of D- and L-MA. The results show that the produced electrode can be used as electrochemical chiral biosensor for MA. (C) 2013 Elsevier Inc. All rights reserved.
