Papers by Jahan-Bakhsh Raoof
Sensors and Actuators B: Chemical, 2018
Research highlights: Label free DNA biosensor for detection of DNA damage in breast cancer 1 ge... more Research highlights: Label free DNA biosensor for detection of DNA damage in breast cancer 1 gene. Diazonium chemistry for stable immobilisation of DNA onto screen-printed carbon electrode. The DNA sensor could detect the protective effect of glutathione against DNA damage. The DNA sensor showed good reproducibility and high stability.
International Journal of Biological Macromolecules, 2018
In this paper, a new and facile method for the electrochemical determination of l-tyrosine was de... more In this paper, a new and facile method for the electrochemical determination of l-tyrosine was designed. First, 3-mercaptopropyl trimethoxysilane-functionalized silica nanoparticles were added to a paper disc. Then, the banana peel tissue and the mediator potassium hexacyanoferrate were dropped onto the paper, respectively. The modified paper disc was placed on the top of the graphite screen printed electrode and electrochemical characterization of this biosensor was studied by cyclic voltammetry and electrochemical impedance spectroscopy methods. The effective parameters like pH, banana peel tissue percentage, and the amount of mediator loading were optimized. l-tyrosine measurements were done by differential pulse voltammetry with a little sample (3 μL) for analysis. The biosensor showed a linear response for l-tyrosine in the wide concentration range of 0.05-600 μM and a low detection limit about 0.02 μM because of the co-catalytic effect of enzyme and nanoparticles. The stability of the biosensor and its selectivity were evaluated. This biosensor was applied for the voltammetric determination of l-tyrosine in the blood plasma sample. The results of the practical application study were comparable with the standard method (HPLC). In conclusion, a simple, inexpensive, rapid, sensitive and selective technique was successfully applied to the l-tyrosine analysis of the little samples.
International Journal of Hydrogen Energy, 2018
Offering new techniques for efficient design and fabrication of inexpensive and earthabundant cat... more Offering new techniques for efficient design and fabrication of inexpensive and earthabundant catalysts for the development of oxygen evolution electrodes is a fundamental approach to promote sustainable energy processes. Herein, we report the in situ synthesis of a novel organic-inorganic composite directly onto carbon paste electrode (CPE) surface, as a robust substrate to incorporate Nickel-Iron (Ni-Fe) metal ions without using any binders or energy consumer techniques. Polyoxometalate (POM) and o-Anisidine (oA) are composite components that can be easily combined on the electrode surface (oA-POM/ CPE). Ascribed to the synergy of context and metal ions, the as-prepared electrode affords a high catalytic activity and stability towards oxygen evolution reaction (OER), and gained a current density of 10 mA cm À2 at overpotential of 330 mV. Moreover, the distinct electrocatalytic activity is illustrated by varying the amount of Fe in immersion solution, which proves the change made in percentage ratio of Ni-Fe in immersion solution that consequently affects Ni-Fe percentage value on electrode surface. This represents the competition between metal cations in creating complex with composite. Collectively, this simple strategy provides a promising way for the development of effective and non-noble metalbased OER electrocatalysts.
Journal of Energy Chemistry, 2017
Facile synthesis and enhanced catalytic activity of electrochemically dealloyed platinum-nickel n... more Facile synthesis and enhanced catalytic activity of electrochemically dealloyed platinum-nickel nanoparticles towards formic acid electrooxidation
Materials science & engineering. C, Materials for biological applications, 2017
A simple low-cost method is proposed to fabricate a functionalized multi-wall carbon nanotube (MW... more A simple low-cost method is proposed to fabricate a functionalized multi-wall carbon nanotube (MWCNT) with 1,1,3,3-tetramethyldisilazane (TMDS) molecule. The techniques of scanning electron microscope (SEM) with electron diffraction and energy dispersive X-ray (EDAX) analysis were applied to characterize the functionalized TMDS-MWCNT. The results showed that a MWCNT with high functionalization of TMDS can be obtained using this simple method. A new nanostructure sensor was constructed based on a glassy carbon electrode modified with TMDS-MWCNT (TMDS-MWCNT/GCE). It was found that the TMDS-MWCNT/GCE exhibits good catalytic activity toward oxidation of pramipexole (PPX) drug, leading to a concentration range of 0.8 to 600μM with a detection limit of 0.2μM at 3σ using the differential pulse voltammetry technique, a sensitivity of 0.084μAμM(-1), and a correlation coefficient of 0.991. Furthermore, the TMDS-MWCNT/GCE was used for PPX detection in tablets and human blood serum samples. The...
Biosensors and Bioelectronics, 2016
In this work, a novel self-powered, sensitive, low-cost, and label-free DNA biosensor is reported... more In this work, a novel self-powered, sensitive, low-cost, and label-free DNA biosensor is reported by applying a two-chambered microbial fuel cell (MFC) as a power supply. A graphite electrode and an Au nanoparticles modified graphite electrode (AuNP/graphite electrode) were used as anode and cathode in the MFC system, respectively. The active biocatalyst in the anodic chamber was a mixed culture of microorganisms. The sensing element of the biosensor was fabricated by the well-known Au-thiol binding the ssDNA probe on the surface of an AuNP/graphite cathode. Electrons produced by microorganisms were transported from the anode to the cathode through an external circuit, which could be detected by the terminal multi-meter detector. The difference between power densities of the ssDNA probe modified cathode in the absence and presence of complementary sequence served as the detection signal of the DNA hybridization with detection limit of 3.1nM. Thereafter, this biosensor was employed for diagnosis and determination of complementary sequence in a human serum sample. The hybridization specificity studies further revealed that the developed DNA biosensor could distinguish fully complementary sequences from one-base mismatched and non-complementary sequences.
Electrochimica Acta, 2016
AgNO 3 PVP Ethylen glycol Ag Nano-Cubes HAuCl 4 Au Nano-Cages Graphene Au Nano-Cages on graphene ... more AgNO 3 PVP Ethylen glycol Ag Nano-Cubes HAuCl 4 Au Nano-Cages Graphene Au Nano-Cages on graphene support (AuNcage/G) 3Ag (s) + AuCl 4-(aq) Au (s) + 3Ag + + 4Cl
International journal of biological macromolecules, 2016
The unique ability of living systems to translate biochemical reactions into mechanical work has ... more The unique ability of living systems to translate biochemical reactions into mechanical work has inspired the design of synthetic DNA motors which generate nanoscale motion via controllable conformational change. It is believable that G-quadruplex structures in certain regions of the genome may play a role in the poor maintenance of genomic stability, which is a characteristic of many types of cancers. In this regards, formation and stabilization of the quadruplex structures at the telomeric repeats is an effective way to hamper the telomere extension and blocking the elongation step. Here, we report a DNA machine for selective Gquadruplex-binding ligand recognition, based on a conformational change; the forces exerted by the precise DNA machine for Gquadruplex conformational change were probed via an electrical signal transducer electrochemically by differential pulse voltammetry and cyclic voltammetry. The proposed machine was prepared by modifying the screen-printed graphite elec...
Energy, 2015
In this paper, a facile electrochemical approach is reported towards the fabrication of Pt needle... more In this paper, a facile electrochemical approach is reported towards the fabrication of Pt needle-like NFs (nanoflowers) at the surface of GCE (glassy carbon electrode). The morphology and composition of the Pt NFs are characterized by SEM (scanning electron microscopy) and EDS (energy dispersive spectroscopy), respectively. Taking methanol oxidation as a model reaction in an acid medium, the electrocatalytic performance of as-prepared Pt NFs has been evaluated by CV (cyclic voltammetry), chronoamperometry and EIS (electrochemical impedance spectroscopy) techniques. These 3D (three dimensional) NFs exhibit the excellent electrocatalytic activity and high level of poisoning tolerance to the carbonaceous oxidative intermediates for the electro-oxidation reaction in acidic media. In addition, EIS information discloses different impedance behaviors for methanol electrooxidation at various potentials on the Pt NFs catalyst and also the change of rate-determining step with increasing potential. The comparison of Pt NFs and Pt NPs (nanoparticles), prepared by electrodeposition in the presence of hydrogen bubbles, shows that the NFs catalyst has higher activity, better long-term stability and lowers Pt loading. The simplicity of method and quality of prepared surfaces suggest applications in catalysis where a convenient method to prepare Pt catalysts with high surface area in one step is desirable.
Chinese Journal of Catalysis, 2014
A novel electrochemical sensor was fabricated by electrodeposition of gold nanoparticles on a pol... more A novel electrochemical sensor was fabricated by electrodeposition of gold nanoparticles on a poly(L-methionine) (PMT)-modified glassy carbon electrode (GCE) to form a nano-Au/PMT composite-modified GCE (nano-Au/PMT/GCE). Scanning electron microscopy and electrochemical techniques were used to characterize the composite electrode. The modified electrode exhibited considerable electrocatalytic activity towards the oxidation of dopamine (DA) and uric acid (UA) in phosphate buffer solution (pH = 7.00). Differential pulse voltammetry revealed that the electrocatalytic oxidation currents of DA and UA were linearly related to concentration over the range of 5.0 × 10-8 to 10-6 mol/L for DA and 7.0 × 10-8 to 10-6 mol/L for UA. The detection limits were 3.7 × 10-8 mol/L for DA and 4.5 × 10-8 mol/L for UA at a signal-to-noise ratio of 3. According to our experimental results, nano-Au/PMT/GCE can be used as a sensitive and selective sensor for simultaneous determination of DA and UA.
Sensors and Actuators B: Chemical, 2015
We developed simple and effective method for the synthesis of Pd-doped mesoporous silica SBA-15 (... more We developed simple and effective method for the synthesis of Pd-doped mesoporous silica SBA-15 (Pd/SBA-15). Techniques of X-ray diffraction, scanning electron microscope, energy dispersive X-ray and nitrogen sorption isotherms techniques were used to characterize the structure and properties of the Pd/SBA-15. Due to the large surface area and high catalytic behavior of Pd/SBA-15, carbon paste electrode modified with Pd/SBA-15 (Pd/SBA-15/CPE) was prepared. The sensor responded linearly to oxalic acid (OA) in the concentration of 10-140 M with a detection limit of 0.4 M at 3 using linear sweep voltammetry. Also, Pd/SBA-15/CPE was used for OA detection in real samples. The proposed method showed a good result, indicating that the present modified electrode could be applied to determine OA in food samples. The accuracy of the method was evaluated as excellent comparing the detection results with that obtained using conventional KMnO 4 titration method. Possible interferences such as glycine, alanine, ascorbic acid, dopamine, uric acid, l-cysteine, glutathione, d-penicillamine, cystamine, N-acetyll-cysteine and lysine for the detection of OA at the Pd/SBA-15/CPE were investigated. The results showed that these mentioned compounds did not show interference.
Chinese Journal of Catalysis, 2011
A carbon paste electrode (CPE) modified with ferrocene carboxylic acid (FcCA) and TiO 2 nanoparti... more A carbon paste electrode (CPE) modified with ferrocene carboxylic acid (FcCA) and TiO 2 nanoparticles was constructed by incorporating TiO 2 nanoparticles and ferrocene carboxylic acid into the carbon paste matrix. The electrochemical behavior of captopril (CAP) at the surface of the modified electrode was investigated using electroanalytical methods. The modified electrode showed excellent electrocatalytic activity for the oxidation of CAP in aqueous solutions at physiological pH values. Cyclic voltammetric curves showed that the oxidation of CAP at the surface of the modified electrode reduced its overpotential by more than 290 mV. The modified electrode was used for detecting captopril using cyclic voltammetry and square wave voltammetry techniques. A calibration curve in the range of 0.03 to 2400 µmol/L was obtained that had a detection limit of 0.0096 µmol/L (3) under the optimized conditions. The modified electrode was successfully used for the determination of captopril in pharmaceutical and biological samples.
Russian Journal of Electrochemistry, 2010
... Jahan Bakhsh Raoofz, Reza Ojani, Mahsa Majidian, and Fereshteh Chekin Electroanalytical Chemi... more ... Jahan Bakhsh Raoofz, Reza Ojani, Mahsa Majidian, and Fereshteh Chekin Electroanalytical Chemical Research Laboratory, Faculty of Chemistry, Mazandaran ... 26. Shahrokhian, S., Amini, MK, Mohammadpoor Bal tork, I., and Tangestaninejad, S., Electroanalysis, 2000, vol. ...
Monatshefte für Chemie - Chemical Monthly, 2011
In this research application of synthesized ZSM-5 zeolite to prepare the modified carbon paste el... more In this research application of synthesized ZSM-5 zeolite to prepare the modified carbon paste electrodes was studied. To prepare of modified electrode, the nickel ions as mediator for electrochemical oxidation of ethanol were doped to ZSM-5 zeolite framework through ion exchange mechanism and oxidation of ethanol on the surface of proposed electrode in the alkaline solution was investigated using cyclic voltammetry and chronoamperometry methods. Also, the catalytic rate constant for oxidation of ethanol (k) was reported.
Measurement, 2014
A carbon-paste electrode modified with vinylferrocene and carbon nanotubes (CNTs) was used for th... more A carbon-paste electrode modified with vinylferrocene and carbon nanotubes (CNTs) was used for the sensitive and selective voltammetric determination of epinephrine. The mediated oxidation of epinephrine at the modified electrode was investigated by cyclic voltammetry (CV). Square wave voltammetry (SWV) of epinephrine at the modified electrode exhibited two linear dynamic ranges with a detection limit of 3.0 Â 10 À8 M. SWV was used for simultaneous determination of epinephrine and tryptophan at the modified electrode, and quantitation of epinephrine and tryptophan in some real samples by the standard addition method.
Journal of the Chinese Chemical Society, 2012
We report a simple and effective strategy for fabrication of the nanocomposite containing chitosa... more We report a simple and effective strategy for fabrication of the nanocomposite containing chitosan (CS) and multiwall carbon nanotube (MWNT) coated on a glassy carbon electrode (GCE). The characterization of the modified electrode (CS-MWNT/GC) was carried out using scanning electron microscopy (SEM) and UV-vis absorption spectroscopy. The electrochemical behavior of CS-MWNT/GC electrode was investigated and compared with the electrochemical behavior of chitosan modified GC (CS/GC), multiwalled carbon nanotube modified GC (MWNT/GC) and unmodified GC using cyclic voltammetry (CV) and electron impedance spectroscopy (EIS). The chitosan films are electrochemically inactive; similar background charging currents are observed at bare GC. The chitosan films are permeable to anionic Fe(CN)6 3−/4− (FC) redox couple. Electrochemical parameters, including apparent diffusion coefficient for the Fe(CN)6 3−/4− redox probe at FC/CS-MWNT/GC electrode is comparable to values reported for cast chitosan films. This modified electrode also showed electrocatalytic effect for the simultaneous determination of Dpenicillamine (D-PA) and tryptophan (Trp). The detection limit of 0.9 μM and 4.0 μM for D-PA and Trp, respectively, makes this nanocomposite very suitable for determination of them with good sensitivity.
Journal of Solid State Electrochemistry, 2008
This paper deals with electrochemical oxidation of formaldehyde in alkaline solution with a new e... more This paper deals with electrochemical oxidation of formaldehyde in alkaline solution with a new electrocatalytic system composed of carbon paste electrode coated with poly (1,5-diaminonaphthalene) (P-1,5-DAN) film containing incorporated Ni(II)/Ni(III) redox ions. The modifier layer of (P-1,5-DAN-Ni)(OH) 2 at the electrode surface acts as a catalyst for the oxidation of formaldehyde in 0.1-M NaOH solution. Cyclic voltammetric and chronoamperometric experiments showed that the formaldehyde can be oxidized at the surface of Ni/P-1,5-DAN-modified carbon paste electrode. In cyclic voltammetry studies, the peak current of the oxidation of nickel hydroxide in the presence of formaldehyde increases and is followed by a decrease in the corresponding cathodic current. The rate constant (k) for the chemical reaction between the formaldehyde and nickel hydroxide has been evaluated by chronoamperometry method. This polymericmodified electrode can oxidize the formaldehyde with high current density (over 7 mA cm −2). Thus, it can be a candidate as an anode for fuel cell applications.
Journal of Solid State Electrochemistry, 2012
ABSTRACT
Journal of Electroanalytical Chemistry, 2009
A highly sensitive glucose detection method was developed using functionalized carbon nanotube bu... more A highly sensitive glucose detection method was developed using functionalized carbon nanotube buckypaper as a free standing electrode in an electrochemical biosensor. Glucose oxidase was immobilized onto various buckypaper samples in order to oxidize glucose resulting in a measureable current/voltage signal output of the biosensor. Cyclic voltammetry (CV) and amperometry were utilized to determine the sensitivity of these buckypaper electrodes. Sensors of three different types of buckypaper were prepared and compared. These modified buckypaper electrode-based sensors showed much higher sensitivity to glucose compared to other electrochemical glucose sensors.
Journal of Electroanalytical Chemistry, 1996
A series of modified carbon paste electrodes were constructed by incorporation of 1,4-naphthoquin... more A series of modified carbon paste electrodes were constructed by incorporation of 1,4-naphthoquinone and some of its derivatives in a graphite powder-mineral oil matrix. It has been shown by cyclic voltammetry, rotating disk electrode voltammetry and chronoamperomeby that these electrodes can catalyze the reduction of 0, to H,O, in aqueous medium (pH > 2). It has been found that in the optimum condition, the reduction of dioxygen at the surface of such electrodes occurs at potentials about 350 to 550mV less negative than at an unmodified carbon paste electrode. The heterogeneous rate constants for the reduction of 0, at the surface of these modified carbon paste electrodes were determined by use of Koutecky-Levich plots. In addition, the apparent diffusion coefficients of modifiers in mineral oil, 0, in solution and the effective area of carbon paste electrodes have also been estimated.
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Papers by Jahan-Bakhsh Raoof