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Analytical & Bioanalytical Electrochemistry - Volume:8 Issue: 4, Jun 2016

Analytical & Bioanalytical Electrochemistry
Volume:8 Issue: 4, Jun 2016

  • تاریخ انتشار: 1395/04/10
  • تعداد عناوین: 10
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  • Ali Bajelani *, Arash Fattah-Alhosseini Pages 409-422
    The corrosion inhibition effect of Licorice hydroalcoholic extract (Licorice extract) was investigated as a green corrosion inhibitor for API 5L Gr.B carbon steel in CO2 environment, using Tafel polarization and electrochemical impedance spectroscopy (EIS) methods. The results showed that Licorice extract can be effective corrosion inhibitor in the CO2 environment and act as an anodic inhibitor. The measurement data revealed that inhibition efficiency increased with the increase of Licorice extract concentration. Thermodynamic calculations indicated that adsorption behavior of Licorice extract on the steel surface obeys Langmuir adsorption isotherm and Licorice extract physically-chemically adsorbed on the steel surface in which adsorption process was spontaneous.
    Keywords: Carbon steel, CO2 corrosion, Green inhibitor, Licorice extract, Langmuir
  • Ebrahim Dasht Razmi, Farshid Ebadi Nejad, Sayed Yahya Kazemi, Seyed Mohammad Abedirad, Reza Alizadeh, Shohreh Jahani, Hadi Beitollahi* Pages 423-431
    The direct electrochemistry of hypercin on a modified carbon paste electrode (CPE) was described. The electrode was modified with zinc oxide (ZnO) nanorods and nhexyl-3-methylimidazolium hexafluoro phosphate as a binder. The oxidation peak potential of hypercin at the surface of the ionic liquid / ZnO nanorods / CPE (ILZNCNPE) appeared at 320 mV, which was about 100 mV lower than the oxidation peak potential at the surface of the traditional carbon CPE under a similar condition. The linear response range and detection limit were found to be 2.5×10-6- 2.0×10-4 M and 9.1×10-7 M, respectively.
    Keywords: Hypecin, ZnO nanorods, Drug analysis, Ionic liquids, Carbon paste electrode
  • Volodymyr V. Tkach *S., Iacute, Lvio C. De Oliveira, Severino C.B. De Oliveira, Virg, Iacute, Nia S. Neves, Reza Ojani, Petro I. Yagodynets Pages 432-441
    The possibility of electrochemical oxidation of procarbazine on cobalt(III) oxyhydroxide in slightly alkaline medium, realized for electroanalytical purposes, has been investigated. The corresponding mathematical model has been analyzed by means of linear stability theory and bifurcation analysis. The optimal conditions for electrooxidation and electroanalytical efficiency of the process have been derived. The possibility of oscillatory and monotonic instabilities was also evaluated.
    Keywords: Cobalt(III) oxy, hydroxide, Procarbazine, Electrooxidation, Electrochemical sensors, Stable steady, state
  • Ali Reza Allafchian*, Seyede Zohreh Mirahmadi-Zare, Seyed Akbar Zahraei Pages 442-452
    The construction and electrochemical response characteristics of polyvinyl chloride (PVC) membrane sensor for the determination of oxycodone are described. An ion– pair of oxycodone–sodium tetraphenyl borate was used as an electroactive material and dibutyl phthalate (DBP) as an anion excluder in a PVC matrix in the percentage ratio of 2.70:61.30:36.00 (w/w). This potentiometric sensor exhibits a linear response to oxycodone in a concentration range of 1.0×10–6 to 1.0×10−2 M with a limit of detection of 9.4×10−7 M and with a slope of -56.10 mV/decade over the pH range 4.0–9.0. The selectivity coefficients of the sensor for oxycodone relative to a numbers of potential interfering compounds were investigated. The sensor is highly selective for oxycodone over a large number of similar compounds. The new sensor showing a fast response time of 15 s and was used over a period of 2 month with a good reproducibility. The sensor was successfully applied to determine oxycodone in urine and blood serum samples with satisfactory results.
    Keywords: Potentiometric sensor, Oxycodone determination, Sodium tetraphenylborate
  • Seyed Morteza Naghib* Pages 453-465
    The aim of this work was fabrication of a nanobiocomposite as a smart biosensor for monitoring glucose. A glucose nanobiosensor based on silver nanoparticles (SNs) and reduced graphene nanosheets (rGNs) composite was successfully fabricated and developed. The SNs-rGNs nanocomposites were successfully prepared and coated on the surface of strip. The reduced graphene nanosheets (rGNs) support incorporated to zero-dimensional Ag nanoparticles arrayed in the third dimension amended a glucose biosensor with superior sensing characteristics. The sensor abilities were certified by changing sensor performance (i.e., sensitivity, limit of detection, and linear range) through using a novel nanocomposite. This approach to fabricate a biosensing device qualifies a high sensitive biosensor design that demonstrated outstanding biological sensing performance such as boosted glucose sensitivity (32 nM limit of detection, 14.1 mAM−1cm−2 sensitivity, 200 nM to 9 mM linear sensing range), a long stable shelf-life (>21 days), and a high selectivity. To the best our knowledge, this device is the first biosensor protocol for glucose monitoring.
    Keywords: Biosensor, Silver nanoparticles, Reduced graphene oxide, Glucose oxidase, Nafion
  • Natalia Zubenia, Zholt Kormosh*, Daria Semenyshyn, Victoria Kochubei, Svitlana Korolchuk, Tanya Savchuk Pages 466-477
    The interaction of organic cation levamisole (Lev) with tropeoline was investigated with the help of thermal studies and IR spectroscopy. These slightly soluble associates were used as electrode active substances (EAS) in plasticized polyvinyl chloride (PVC) membranes of ion-selective electrodes (ISE), sensitive to organic cation levamisole. Based on the experimental data, a new method of levamisole determination in industrial products by direct potentiometry with the help of membrane sensor was developed.
    Keywords: Electrode active substance, Levamisole, Membrane sensor, Direct potentiometry, IR spectroscopy
  • Foroozan Hasanpour*, Masoumeh Taei, Hassan Hadadzadeh, Razieh Ziaei Pages 478-488
    A novel Zn(II)-fluorophore complex, tris(1,10-phenanthroline-5,6-dione)zinc(II) hexafluorophosphate, has been synthesized and structurally characterized for modification of carbon paste electrode. Then the fabricated electrode was applied as a highly selective and sensitive sensor for determination of penicillinamine. Despite of featureless voltammetric response of this complex in the range of .4 to .0 V, it exhibits potent electrocatalytic activity toward D-PA oxidation at .8 V. Impedance Spectroscopy (EIS) was used for comparing the surface electron transfer resistance of the modified and bare electrode and demonstrate that modified electrode make the electron transfer easier. Under the optimum conditions (pH=4.0), the oxidation current of penicillinamine was linearly related to its concentration in the range of 0.1-95.0 μmol L-1 with a detection limit of 0.05 μmol L-1 at the signal to noise of 3. Satisfactory results were achieved for determination of penicillinamine in serum samples of patients with rheumatoid arthritis using standard addition method.
    Keywords: D, penicillamine, Tris(1, 10, phenanthroline, 5, 6, dione)zinc(II) hexafluoro phosphate, Carbon paste electrode, Electrochemical sensor
  • Nanomolar Simultaneous Determination of Amlodipine and Uric acid at the Novel Carbon Paste Electrode Modified with Magnetic Carbon Nanotubes/Diatomite Earth Composite
    Ali Babaei* Pages 489-504
    In this work, we use synthesized magnetic carbon nanotubes/diatomite earth composite (CNTs/DE) to fabricate the novel modified carbon paste electrode (CNTs/DE/CPE). The modified electrode was developed and used as a sensitive electrochemical sensor for simultaneous determination of amlodipine (AML) and uric acid (UA). Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CA) methods were used for the measurements. The presence of the CNTs/DE in the electrode composite leads to rapid acceleration in electron transfer reaction of AML and UA at CNTs/DE/CPE. Under optimized conditions and using DPV method, the modified sensor provides a linear response versus UA and AML concentrations in the range of 0.02–250 and 0.04–140μM and with a detection limit of 0.011 μM and 0.021 μM (S/N=3), respectively. The fabricated sensor offered numerous advantages such as excellent sensitivity, good stability and high selectivity toward UA and AML determination. The modified electrode was used for determination of UA and AML in human urine and serum with satisfactory results.
    Keywords: Amlodipine, Uric acid, Carbon nanotubes, Diatomite earth composite, Carbon paste electrode
  • Abdul Motina*, Nazim Uddina, Palash K. Dhara, M. A. Hafiz Miaa, Abul Hashemb Pages 505-521
    Electrochemical oxidation of catechol generates o-benzoquinone which acts as Michael acceptor and its reaction has been studied in the presence of different concentration of aspartic acid in aqueous solution with various pH values, different electrodes using cyclic voltammetry, controlled potential coulometry and differential pulse voltammetry. In this investigation aspartic acid behaves as a nucleophile and undergoes 1,4-Michael addition reaction with catechol. The participation of reaction of o-benzoquinone with aspartic acid at moderately higher concentration of nucleophiles in the second scan of potential was observed. The products synthesized from the reaction are assumed to be 2-((3,4dioxocyclohexa-1,5-dien-1-yl)amino)succinic acid that undergo electron transfer at more negative potentials than the catechol’s. The effect of pH on catechol in presence of aspartic acid was studied by varying pH from 5 to 11. The concentration effect of nucleophiles with the fixed concentration of catechol (2 mM) was measured from 30 mM to 100 mM. The reaction was strongly influenced by the pH as well as concentration of aspartic acid. This nucleophilic addition reaction was mostly suitable in 70 mM of aspartic acid and 2 mM of catechol at pH 7. The behavior of the reaction was of ECE type followed by diffusion mechanism.
    Keywords: Electro, oxidation, Favorable condition, Aspartic acid, Catechol, Voltammetry, Controlled potential coulometry
  • Hossein Rajabi *, Meissam Noroozifar, Mozhgan Khorasani-Motlagh Pages 522-534
    A graphite paste electrode (GPE) modified with 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) and multi-walled carbon nanotube (MWCNT), was prepared for simultaneous voltammetric determination of epinephrine (EN) and xanthine (XN). The prepared electrode (BMIMPF6–MWCNT/GPE) showed an excellent catalytic activity in the electrochemical oxidation of EN and XN, leading to remarkable enhancements in the corresponding peak currents and lowering the peak potentials. The peaks current of linear sweep voltammograms (LSV) of EN and XN increased linearly with their concentration in the ranges of 0.30–60 µmol L−1 EN and 0.20–45 µmol L−1 XN in 0.1 M phosphate buffer solution (pH 7.0). The effects of both scan rate and pH on the anodic peak height of the EP oxidation and XN were discussed. The lowest detection limits (S/N= 3) were 0.209 µmol L−1 and 0.143 µmol L−1 for EP and XN, respectively. Therefore, the applicability of the voltammetric biosensor was demonstrated by simultaneous determination of EP and XN in human urine, human blood serum and ampoule. This modified electrode showed a good stability and repeatability during experiments.
    Keywords: 1, Butyl, 3, methylimidazolium hexafluorophosphate, Voltammetric determination Sensor, Epinephrine, Xanthine