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Analytical & Bioanalytical Electrochemistry - Volume:9 Issue: 4, Jun 2017

Analytical & Bioanalytical Electrochemistry
Volume:9 Issue: 4, Jun 2017

  • تاریخ انتشار: 1396/04/10
  • تعداد عناوین: 10
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  • Nosrat Mohammadizadeh*, Sayed Zia Mohammadi, Massoud Kaykhaii Pages 390-399
    A fast and selective electrochemical sensor for determination of amlodipine was developed based on ZrO2 nanoparticles modified glassy carbon electrode. Amlodipine could be determined directly by electrochemical oxidization with the modified electrode. ZrO2 nanoparticles increased electrochemical response to amlodipine. Experimental variables, such as the deposited amount of the modifier suspension, pH of the supporting electrolyte and the potential scan rate were optimized by monitoring the electrochemical responses of amlodipine. Under the optimum conditions, the modified electrode showed a wide linear dynamic range of 10.0–200.0 μM with a detection limit of 2.0 μM for the voltammetric determination of amlodipine. The prepared modified electrode showed high sensitivity, stability and good reproducibility in response to amlodipine, confirming its usability for the accurate determination of trace amounts of amlodipine in pharmaceutical and clinical preparations.
    Keywords: Amlodipine, ZrO2 nanoparticles, Glassy carbon electrode, Voltammetry
  • Gujapaneni Venkataprasad, Tukiakula Madhusudana Reddy*, Pinjari Shaikshavali, Palla Gopal, Palakollu Venkata Narayana Pages 400-411
    In this work, the glassy carbon electrode (GCE) was modified with multi-walled carbon nanotubes (MWCNTs) by drop casting process, and it was used as a working electrode for the electrochemical determination of 3,5-dinitrobenzoic acid (3,5-DNBA) in an electrolytic solution containing a cetyl trimethyl ammonium bromide (CTAB). This process was examined by using differential pulse voltammetry (DPV) and cyclic voltammetry (CV) techniques. The modified electrode showed an excellent electrocatalytic activity and sensitivity towards the investigation of 3,5-DNBA reduction behavior in the presence of CTAB. The electrochemical process was irreversible and was controlled by adsorption. The effect of pH, scan rate and concentration were studied at the surface of MWCNTs/GCE. The electrochemical behavior of 3,5-DNBA was studied in the presence and absence of CTAB at MWCNTs/GCE in PBS having pH 6.5. The LOD (limit of detection) and LOQ (limit of quantification) of 3,5-DNBA was found to be as 4.94×10-6 M, 1.65×10-5 M respectively. The surface coverage area concentration (Γ) of MWCNTs/GCE was calculated and was found to be as 1.3146×10-8 mole/cm2. By using electrochemical impedance spectroscopy (EIS), the interfacial electron transfer behavior of 3,5-DNBA was studied at different types of electrode surfaces.
    Keywords: 3, 5-DNBA, MWCNTs, CTAB, CV, DPV, EIS
  • Ali Reza Madram*, Mahbubeh Faraji Pages 412-423
    Olivine-type lithium iron phosphate (LiFePO4) attracted much attention as a promising cathode material for lithium-ion batteries (LIBs). Various processes have been developed to synthesize LiFePO4 or LiFePO4/C (carbon coating on LiFePO4), and some of them are being used to mass produce LiFePO4/C at the commercial or pilot scale. The solid-state method has already been widely adopted by industry for mass production, and it will remain one of the most used processes for manufacturing LiFePO4/C due to process simplicity and low cost. LiFePO4 and LiFePO4/C are successfully prepared by a simple solidstate reaction. The structure of the LiFePO4 and LiFePO4/C is investigated by X-ray diffraction (XRD). The morphology, particle size and carbon coating layer of the samples are observed using scanning electron microscopy (SEM), Brunauer, Emmett, and Teller (BET) method and transmission electron microscopy (TEM). Furthermore, the electrochemical properties are evaluated by cyclic voltammograms (CVs), electrochemical impedance spectra (EIS) and constant current charge/discharge cycling tests. The results show that LiFePO4/C can deliver better battery performance than the bare LiFePO4. It delivers a discharge capacity of 168 (0.1C), 152 (0.2C), 138 (1C), 130 (2C) and 105 mAh g-1 (5C), respectively.
    Keywords: Lithium-ion batteries (LIBs), Cathode material, LiFePO4, Carbon coating, Cyclic voltammetry, Ball milling
  • Tandreborekaval Swamy Naik Sunil Kumar Naik, Bahaddurghatta Eshwaraswamy Kumara Swamy* Pages 424-438
    The phenosafranine (PS) and sodium alpha olefin sulphonate (SAOS) used as the modifiers for the modification of bare carbon paste electrode (BCPE). Electropolymerization and immobilization technique has been employed for the modification of carbon paste electrode to get poly (phenosafranine)/SAOS/MCPE. The electrocatalytic behaviour of the modified electrode was investigated by voltammetric techniques. The modified electrode exhibits excellent electrocatalytic activity towards the determination of dopamine (DA) and uric acid (UA) in presence of 0.2 M phosphate buffer solution (PBS) at pH 7.4 with the scan rate of 50 mVs-1. The various parameters like effects of scan rate, concentration and pH variation was studied and the overall electrode process was found to be adsorption-controlled at poly (phenosafranine) /SAOS/MCPE . Both dopamine and uric acid exhibit good detection limits at modified electrode (4.43 µM and 4.18 µM respectively). Hence, the proposed sensor shows good sensitivity towards the determination of DA and UA individually and simultaneously.
    Keywords: Dopamine, Uric acid, Poly (phenosafranine), Sodium alpha olefin sulphonate, Modified carbon paste electrode, Cyclic voltammetry
  • Maryam Dashti-Ardakani, Hamid Reza Zare-Mehrjardi *, Hadi Kargar Pages 439-452
    The complex N,N'-bis(5-Chloro salicylidene) 2,2-dimethyl-1,3-propandiamino cobalt (II) chloride (CoClSal) and 1-octanaminium,N,N,N-trioctyl bromide (as a cationic surfactant) are used for the preparation of the modified carbon paste electrode (CPE). The cyclic and differential pulse voltammetric methods (CV and DPV) used to study of the electrochemical behavior of ascorbic acid (AA) and dopamine (DA) at the surface of the cobalt Schiff base complex-modified CPE containing different percents of cationic surfactant. The effects of the buffered solution pH and potential sweep rate on the electrode response and the resolution between the anodic peaks of AA and DA are studied by CV and DPV. Using the modified electrode, the best peak separation (344 mV) for these compounds is obtained in solutions with pH 5.0. Surface regeneration and the very easy preparation of the modified CPE together with the efficient electrocatalytic property, very good peak resolution and reproducibility of its voltammetric responses designate the modified CPE in this work appropriate for simultaneous voltammetric determination of DA and AA.
    Keywords: Modified electrode, Surfactant, Dopamine, Differential pulse voltammetry
  • Ali Kamal Attia *, Noha Salem Rashed, Manal Mohamed Fouad, Reem Adel Wasfy Pages 453-468
    A simple, precise, accurate and inexpensive voltammetric method was developed for the quantitative determination of tolfenamic acid at modified glassy carbon electrode in phosphate buffer of pH 7.2. Several factors such as type of buffer, type of surfactant; scan rate and accumulation time were studied to obtain the optimum conditions for the determination of tolfenamic acid. The proposed method shows linearity in concentration range of 6.0×10-7-6.0×10-6 mol L-1 with mean percentage recovery of 101.2±1.99. The limits of detection and quantification were 1.43×10-7 mol L-1 and 4.34×10-7 mol L-1, respectively. The proposed voltammetric method was successfully applied to determine tolfenamic acid in pharmaceutical formulations and human urine. The results of the proposed method were statistically compared with those of a reported method and showed no significant difference. Thus, it can be used as quality control for this drug in laboratories.
    Keywords: Tolfenamic acid, Voltammetry, Modified electrode, Pharmaceutical analysis
  • Mustafa Aghazadeh, Ali Ahmadi* Pages 469-479
    We reported here a simple electro-synthesis procedure to synthesize an extremely high specific surface area (SSA) yttrium oxide (Y2O3) nanopowder. The mesoporous (pore diameter, d≈8 nm) Y2O3 powder was deposited by a two-step process involving the pulse cathodic electro-deposition (PC-ED) of yttrium hydroxide film from nitrate bath at 70 oC temperature followed by calcination at 600 C in air for 3 h. The applied pulse parameters i.e. peak current density, on-time and off-time were Ip=25 mA/cm2, ton=1ms and toff=5ms, respectively. The products were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy methods. The obtained data proved that the fabricated product had pure cubic Y2O3 crystal structure and is composed thin wall-like morphology with SAA value of 243.7 m2/g and mean pore size of 9 nm. From these findings, the PC-ED procedure was proposed for facile fabrication of high-SSA Y2O3 nanopowder.
    Keywords: Yttrium oxide, Surface area, Nanopowder, Heat treatment, Cathodic electrosynthesis
  • Muhammad Nurdin*, Ahmad Zaeni, Efraim Tasik Rammang, Maulidiyah Maulidiyah, Dwiprayogo Wibowo Pages 480-494
    Development of Chemical Oxygen Demand (COD) flow system has been conducted by using TiO2/Ti electrode. This study aims to develop the flow system portable reactor can be used for determination of COD value as a model design in a river, gutter, and disposal of industrial wastewater. A highly ordered the TiO2 nanostructure was grown onto Ti plate by anodizing method then calcinated in temperature 500 °C for 1.5 h. The electrochemical test on TiO2/Ti electrode was performed by using Linear Sweep Voltammetry technique to investigate the high photo-oxidation when ultraviolet (UV) light irradiation. Specifically, the determination of COD value of Sodium Lauryl Sulfate, Hexadecyltrimethylammonium bromide, and 4-oktilfenol poly-ethoxylate surfactants in flow system was applied by using Multi-Pulse Amperometry technique based on Faraday’s Law (Q=∫ Inet dt). The excellent sensing of COD value using TiO2/Ti electrode by flow system showed that SLS, HDTMA-Br, and Triton X-100 surfactants in the concentrations of 1.0 mg/L, 3.0 mg/L, 5.0 mg/L, 7.0 mg/L, and 9.0 mg/L were (1.33 mg/L, 2.92 mg/L, 4.63 mg/L, 6.68 mg/L and 9.43 mg/L); (0.78 mg/L, 3.25 mg/L, 5.21 mg/L, 7.42 mg/L and 9.06 mg/L), and (0.71 mg/L, 3.21 mg/L, 5.05 mg/L, 7.42 mg/L and 8.61 mg/L), respectively.
    Keywords: COD sensor, TiO2-Ti electrode, Photoelectrocatalysis, Surfactants, Flow system
  • Mohammad Mehdi Foroughi*, Somayeh Tajik * Pages 495-505
    SiO2@Fe3O4/GR nanocomposite decorated graphene modified carbon ionic liquid electrode (SiO2@Fe3O4/GR/IL/CPE) was prepared. The electrochemical behavior of tyrosine was studied in 0.1 M phosphate buffer solution (PBS) of pH 7.0 using cyclic voltammetry (CV) while differential pulse voltammetry (DPV) was used for quantification. Under optimum condition, the DPV response offered linear dynamic range for tyrosine in the concentration range 1.0×10−6 M–8.0×10−4 M with detection limit 5.0×10−7 M (S/N=3). The method was successfully applied for determination of tyrosine in real samples.
    Keywords: Tyrosine, Ionic liquid, SiO2@Fe3O4-GR nanocomposite, Carbon paste electrode
  • Duddukuru Saritha, Sundupalle Kiranmai, Chougoni Madhuri, Manthrapudi Venu, Kayam Guramma Rajyalakshmi, Gajulapalli Madhavi * Pages 506-520
    An electrochemical sensor was developed by decorating a newly synthesized iron oxide magnetite nanoparticle capped silica dioxide (Fe3O4@SiO2 microspheres) on the surface of carbon paste electrode. The developed sensor was further used in the electrochemical determination of Rutin (Vitamin P). Cyclic and differential pulse voltammetric methods were carried out to study the kinetic parameters and the quantitative determination of Rutin respectively. Phosphate buffer solution (0.1 M) with pH 7.5 was used as supporting electrolyte in the present investigation. Various parameters like effect of pH, effect of concentration and effect of scan rate were studied in a systematic manner. A set of cyclic voltammogram redox peaks of Rutin was appeared at 397.2 mV (Epa) and 367.8 mV (Epc). The anodic peak currents were linearly increased with increase in the concentration of Rutin with a dynamic range of 1.6×10−6-1.6×10−5 M. The detection limit was calculated and found to be 1.43×10−6 M. Electrochemical parameters viz., number of electrons transferred (n), electrode reaction rate constant (ks), and the charge transfer coefficient (α), were calculated and found to be 2.0, 0.00149 and 1.09 respectively. Further the developed novel electrochemical sensor was successfully applied for the determination of real samples analysis. The results concluded that the Fe3O4@SiO2 modified carbon paste electrode (FSMCPE) has showed the long lasting stability, high sensitivity and low detection limits, towards the determination of Rutin.
    Keywords: Fe3O4@SiO2, Rutin, Cyclic Voltammetry, Differential pulse Voltammetry