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    Localized surface plasmon resonance sensor for simultaneous kinetic determination of peroxyacetic acid and hydrogen peroxide

    , Article Analytica Chimica Acta ; Volume 762 , 2013 , Pages 87-93 ; 00032670 (ISSN) Tashkhourian, J ; Hormozi Nezhad, M. R ; Khodaveisi, J ; Dashti, R ; Sharif University of Technology
    2013
    Abstract
    A new sensor for simultaneous determination of peroxyacetic acid and hydrogen peroxide using silver nanoparticles (Ag-NPs) as a chromogenic reagent is introduced. The silver nanoparticles have the catalytic ability for the decomposition of peroxyacetic acid and hydrogen peroxide; then the decomposition of them induces the degradation of silver nanoparticles. Hence, a remarkable change in the localized surface plasmon resonance absorbance strength could be observed. Spectra-kinetic approach and artificial neural network was applied for the simultaneous determination of peroxyacetic acid and hydrogen peroxide. Linear calibration graphs were obtained in the concentration range of (8.20×10-5 to... 

    Construction of a modified carbon paste electrode based on TiO2 nanoparticles for the determination of gallic acid

    , Article Journal of Solid State Electrochemistry ; Volume 17, Issue 1 , 2013 , Pages 157-165 ; 14328488 (ISSN) Tashkhourian, J ; Nami Ana, S. F ; Hashemnia, S ; Hormozi Nezhad, M. R ; Sharif University of Technology
    2013
    Abstract
    A modified carbon paste electrode was prepared by incorporating the TiO2 nanoparticles in the carbon paste matrix. The electrochemical behavior of gallic acid (GA) is investigated on the surface of the electrode using cyclic voltammetry and differential pulse voltammetry. The surface morphology of the prepared electrode was characterized using the scanning electron microscopy. The results indicate that the electrochemical response of GA is improved significantly at the modified electrode compared with the unmodified electrode. Furthermore, the capabilities of electron transfer on these two electrodes were also investigated by electrochemical impedance spectroscopy. Under the optimized... 

    Fabrication of modified TiO 2 nanoparticle carbon paste electrode for simultaneous determination of dopamine, uric acid, and l-cysteine

    , Article Journal of Solid State Electrochemistry ; Volume 13, Issue 9 , 2009 , Pages 1433-1440 ; 14328488 (ISSN) Mazloum Ardakani, M ; Talebi, A ; Naeimi, H ; Nejati Barzoky, M ; Taghavinia, N ; Sharif University of Technology
    2009
    Abstract
    A carbon paste electrode, modified with 2, 2″-[1,7- hepthandiylbis(nitriloethylidyne)]-bis-hydroquinone and TiO 2 nanoparticles, was used for the simultaneous determination of dopamine (DA), uric acid (UA), and l-cysteine. The study was carried out by using cyclic voltammetry, chronoamperometry, and square wave voltammetry (SWV) techniques. Some kinetic parameters such as the electron transfer coefficient (α) and heterogeneous rate constant (k s) were also determined for the DA oxidation. A dynamic range of 8.0-1400 μM, with the detection limit of 8.4∈×∈10 -7 M for DA, was obtained using SWV (pH∈=∈7.0). The prepared electrode was successfully applied for the determination of DA, UA, and... 

    Silver nanoparticles modified carbon nanotube paste electrode for simultaneous determination of dopamine and ascorbic acid

    , Article Journal of Electroanalytical Chemistry ; Volume 633, Issue 1 , 2009 , Pages 85-91 ; 15726657 (ISSN) Tashkhourian, J ; Hormozi Nezhad, M. R ; Khodavesi, J ; Javadi, S ; Sharif University of Technology
    Elsevier  2009
    Abstract
    A novel modified carbon-paste electrode was employed for the simultaneous determination of dopamine (DA) and ascorbic acid (AA) with good selectivity and high sensitivity. Silver nanoparticle and carbon nanotube modified carbon-paste electrode (Ag/CNT-CPE) displayed excellent electrochemical catalytic activities towards dopamine (DA) and ascorbic acid (AA). The oxidation overpotentials of DA and AA were decreased significantly compared with those obtained at the bare CPE. Differential pulse voltammetry was used for the simultaneous determination of DA and AA. The peak separation between DA and AA was 67 mV. The calibration curves for DA and AA were obtained in the range of 8.0 × 10-7-6.4 ×... 

    A novel photometric glucose biosensor based on decolorizing of silver nanoparticles

    , Article Sensors and Actuators, B: Chemical ; Volume 158, Issue 1 , November , 2011 , Pages 185-189 ; 09254005 (ISSN) Tashkhourian, J ; Hormozi Nezhad, M. R ; Khodaveisi, J ; Dashti, R ; Sharif University of Technology
    2011
    Abstract
    A novel glucose biosensor based on chromophore (silver nanoparticles) decolorizing for the photometric determination of glucose was developed. Silver nanoparticles are directly synthesized in the sol-gel matrix by a one-step method based on the reduction of the inorganic precursor AgNO3 and were used for the preparation, characterization and calibration of a highly sensitive and cost-effective localized surface plasmon resonance-based glucose biosensor. In the presence of glucose oxidase (GOx) and due to the enzyme-substrate (glucose) reaction, H2O2 was produced and silver nanoparticles in the sol-gel glass have the ability for the decomposition of hydrogen peroxide. Due to the degradation... 

    Application of pyrolytic graphite modified with nano-diamond/graphite film for simultaneous voltammetric determination of epinephrine and uric acid in the presence of ascorbic acid

    , Article Electrochimica Acta ; Volume 55, Issue 28 , 2010 , Pages 9090-9096 ; 00134686 (ISSN) Shahrokhian, S ; Khafaji, M ; Sharif University of Technology
    2010
    Abstract
    A novel modified pyrolytic graphite electrode with nano-diamond/graphite was fabricated. The electrochemical response characteristics of the modified electrode toward the epinephrine (EN) and uric acid (UA) were studied by means of cyclic and linear sweep voltammetry. The structural morphology and thickness of the film was characterized by SEM technique. The prepared electrode showed an excellent catalytic activity in the electrochemical oxidation of EN and UA, leading to remarkable enhancements in the corresponding peak currents and lowering the peak potentials. The prepared modified electrode acts as a highly sensitive sensor for simultaneous determination of EN and UA in the presence of...