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Analytical & Bioanalytical Electrochemistry - Volume:10 Issue: 7, Jul 2018

Analytical & Bioanalytical Electrochemistry
Volume:10 Issue: 7, Jul 2018

  • تاریخ انتشار: 1397/05/10
  • تعداد عناوین: 10
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  • Arash Fattah-Alhosseini *, Ghazaleh Ansari, Omid Imantalab Pages 805-814
    Passive film of nano-grained pure copper was examined for semiconducting behavior in comparison to annealed pure copper. Mott–Schottky analysis revealed the vacancies behavior through the passive layer, and the Point Defect Model (PDM) put an accurate interpretation on the survey data. The findings clarify that the vacancy of copper is the main in the passive layer on both annealed and nano-grained pure copper formed anodically in 0.1 M KOH electrolyte. Also, calculations based on PDM showed that the diffusion coefficient of the copper vacancy for nano-grained sample reached to 17.11×10 17 cm2/s from 12.05×10-17 cm2/s of the initial annealed one.
    Keywords: Pure copper, Nano-grained, Mott–Schottky analysis, Diffusion coefficient, Copper vacancy
  • Mohamed El Faydy, Mouhsine Galai, Mohamed Rbaa, Moussa Ouakki, Brahim Lakhrissi, Mohamed Ebn Touhami, Younes El Kacimi * Pages 815-839
    New quinoline, namely 5-penthylaminomethyl-8-hydroxyquinoline (P-QN) has been synthesized and characterized by different spectral methods such as 1H NMR and 13C NMR. Their inhibitive action against the corrosion of carbon steel in 1.0 M hydrochloric acid solution were investigated at different temperatures in the range from 25±2 to 55±2 °C by a series of known techniques such weight loss, electrochemical impedance spectroscopy (EIS) and Tafel polarization measurements. The obtained results show that compound (P-QN) is a very good inhibitor with efficiency of 93.3% at 10-3 M additive concentration in 1.0 M HCl solution. Generally the inhibition efficiency increased with increase of inhibitor concentration. Changes in impedance parameters (Rct and Cdl) were indicative of adsorption of compound (P-QN) on the metal surface, leading to the formation of a protective film. Tafel polarization measurements showed that the inhibitor (P-QN) is a mixed type. The adsorption of the inhibitor on the surface of carbon steel in 1.0 M HCl solution was found to obey Longmuir’s adsorption isotherm. The kinetic and thermodynamic parameters for carbon steel corrosion and inhibitor adsorption, respectively, were determined and discussed. On the bases of thermodynamic adsorption parameters, comprehensive adsorption (physisorption and chemisorption) for the studied inhibitors on carbon steel surface was suggested.
    Keywords: Quinoline derivatives, Corrosion inhibition, Carbon steel, Hydrochloric Acid, EIS
  • Sahar Nayeri, Taher Alizadeh * Pages 840-850
    Graphite/AgCl composite is described as an efficient electrocatalyst for the electroxidation of oxalic acid (OA). Graphite/AgCl was synthesized by the precipitation of AgCl on graphite sheet via drop wise addition of Cl- into an Ag solution, containing dispersed graphite. The material obtained was characterized by scanning electron microscopy. The composite was mixed with mineral oil as binder and used as carbon paste electrode for electrocatalytic oxidation of OA. The composite electrode exhibited appropriate catalytic activity for the electrooxidation of OA, leading to a substantial increase in anodic peak current, in comparison with the unmodified carbon paste electrode. Electrochemical impedance spectroscopy showed a substantial decrease in charge transfer resistance of OA oxidation at graphite/AgCl composite electrode, compared to that graphite paste electrode. The electrode showed appropriate selectivity compared to some compounds like citric acid, lactic acid, ascorbic acid and tartaric acid. Cyclic voltammetry at different scan rates and also various pH conditions gave some evidences about the mechanism electrooxidation of OA at graphite/AgCl electrode.
    Keywords: Graphite-AgCl composite is described as an efficient electrocatalyst for the
  • H.G. Daabees, Wael Talaat, Manal El-Shal, Kholoud Ahmed* Pages 851-872
    This article pronounces differential pulse and square wave voltammetric techniques for determination of Nepafenac in pharmaceutical dosage form and human serum. The proposed techniques were established on electro-oxidation of nepafenac at two electrodes, the first electrode is carbon paste modified with carbon multiwalled nanotubes and plated with Gold nanoparticles (GN-CMWNT-CPE) in 0.1 M HCl and the second electrode is the carbon paste modified with multiwalled carbon nanotubes and 1-n-butyl- - methylpyridinium hexafluorophosphate ion crystal and plated with Gold nanoparticles particles (GN-CMWNT-BMH-CPE) in 0.1 M H2SO4. The peak current concentration relationship was rectilinear over the range 3.33-36.63 and 6.67- 46.69 μg/mL for (GN-CMWNT-BMH-CPE) in DPV and SQW modes, respectively, and 6.67-33.35 μg/mL and 6.67-40.02 μg/mL for (GN-CMWNT- -CPE) in both DPV and SQW modes. LOD was 0.557 and 0.929 μg/mL for (GN-CMWNT-BMH-CPE) in DPV and SQW modes, respectively, 1.213 and 0.806 μg/mL for (GN-CMWNT- -CPE) in both DPV and SQW modes. Experimentations were optimized using glassy electrode. Precision and accuracy of were checked with good repeatability and reproducibility. The methods were applied successfully to the pharmaceutical dosage form and human serum.
    Keywords: Gold nanoparticles, Electroanalysis, Nepafenac, Glassy electrode, Biological fluid
  • Sedighe Akbari, Somayeh Tajik*, Hadi Beitollahi, Shohreh Jahani, Hadi Hassani Nadiki, Pouria Biparva, Rahman Hosseinzadeh Pages 873-889
    Levodopa, one of the prescribed medications in Parkinson disease, is electrochemically determined here. A Cu/TiO2 nanocomposite/room temperature ionic liquid/2-(ferrocenylethynyl)fluoren-9-one modified carbon paste electrode (Cu/TiO2-IL- 2FF/CPE) was used for the electrochemical determination of levodopa. The electro oxidation mechanism of levodopa at Cu/TiO2-IL-2FF/CPE was also studied. The obtained data showed that the electro-oxidation of levodopa at the Cu/TiO2-IL-2FF/CPE is greatly facilitated, which is attributed to high electrical conductivity of Cu/TiO2 nanocomposite, room temperature ionic liquid and 2-(ferrocenylethynyl)fluoren-9-one. The Cu/TiO2-IL-2FF/CPE showed a good electron mediating behavior followed by well separated oxidation signals of levodopa and tyrosine. Differential pulse voltammetric peak current showed a linear relationship corresponds to the concentrations of levodopa in a linear range of 0.03 to 700.0 μM with detection limit of 12.0 nM. The Cu/TiO2-IL-2FF/CPE shows excellent ability to determination of levodopa and tyrosine in real samples.
    Keywords: Levodopa, Tyrosine, Cu-TiO2 nanocomposite, Room temperature ionic liquid, 2-(ferrocenylethynyl)fluoren-9-one, Carbon paste electrode, Voltammetry
  • Kallappa Deepa, Thimmappavenkatarangaiah Venkatesha * Pages 890-900
    NiO-ZrO2 nanoparticles were synthesized by co-precipitation method and characterized by XRD, SEM and EDAX techniques. The XRD and SEM studies were used to analyze the size and morphology of the nanoparticles. The elemental composition of the prepared particles was detected by EDAX analysis. The particles were used in the generation of Zn/NiO-ZrO2 composite coating on mild steel by electroplating. The surface morphology and elemental composition of the coated samples were examined by scanning electron microscopy (SEM) images and EDAX analysis respectively. The anticorrosion behavior of Zn/NiO-ZrO2 composite coating was electrochemically studied by Tafel polarization and electrochemical impedance spectroscopy in comparison with pure zinc coating.
    Keywords: NiO-ZrO2 nanoparticles, Composite coating, Electrochemical impedance spectroscopy, Tafel
  • Mohammad Reza Ganjali *, Morteza Rezapour Pages 901-911
    Here, we report an electrochemical procedure for facile fabrication of cobalt cations doped iron oxide (Co-IO) /graphene composite. The superparamagnetic CoxFeII1-xFeIII2O3 nanoparticles are electrochemically grown onto graphene sheets via cathodic electro-synthesis. The graphene sheets are also electrophoretically deposited onto cathode electrode from an aqueous graphene dispersed solution. The Co2 doped magnetite nanoparticles are also deposited from Fe(NO3)3, FeCl2 and Co(NO3)2 with molar ratios of 1:0.5:0.5, respectively. The magnetite crystal nature of the fabricated composite was proved through XRD and IR data. Cobalt content (i.e. doped Co2 ions) in the prepared composite was established by data obtained from energy-dispersive X-ray spectroscopy (EDS). The results of SEM and IR analyses confirmed the electrophoretic deposition of dispersed graphene layers onto cathode surface. The superparamagnetic nature of the fabricated CoxFeII1-xFeIII2O3/graphene sample was verified by vibrating sample magnetometer (VSM) data. Based on the results obtained, it is confirmed that cathodic electrochemical route is facile technique for fabrication of graphene based magnetite nanocomposite.
    Keywords: Iron oxide, Metal ion doping, Graphene, Electro-chemical synthesis, Nanocomposite
  • Sarra Aourabi *, Majid Driouch, Kenza Ammor, Mouhcine Sfaira, Mohamed Ebn Touhami, Fatima Mahjoubi Pages 912-929
    The present work concerns the valorization of ethanolic extract of the aerial part of Ammi visnaga, as an antioxidant as well as a corrosion inhibitor for mild steel in 1 M HCl medium. The antioxidant activity was evaluated by two techniques; total antioxidant capacity and free radical scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH). The phytochemical tests were carried out by colorimetric reactions and precipitation which revealed an intense presence of tannins and Flavonoids. The total phenol, flavonoid and condensed tannin content were conducted according to the Folin Ciacalteu, Quettier-Deleu and Broadhurst methods, respectively. The results showed that the ethanolic extract of Ammi visnaga was rich of polyphenols. Ethanolic extract had a great radical scavenging activity (IC50=2.82 mg/mL) when compared to the standard BHT (IC50=0.27 mg/mL) along with a high total antioxidant capacity (82.46 mg BHT/g extract). On the other hand, the anticorrosion behavior of ethanolic extract of Ammi visnaga was conducted by electrochemical impedance spectroscopy, potentiodynamic polarization and mass-loss measurements. Polarization curves indicated that ethanolic extract of Ammi visnaga acts as mixed-type inhibitor. Impedance measurements showed that the double-layer capacitance decreased and charge-transfer resistance increased with rise of ethanolic extract of Ammi visnaga concentration and thereby increased the inhibition efficiency. The adsorption of the extracted molecules followed the Langmuir adsorption isotherm model. It was registered that ethanolic extract of Ammi visnaga exhibited both an important antioxidant and anticorrosive properties.
    Keywords: Extract of Ammi visnaga, Total phenol, Flavonoids, Condensed tannin, Antioxidant activity, Corrosion inhibition
  • Fatemeh Ghasemi, Mehdi Salehi* Pages 930-942
    In this research, the synthesis of copper oxide nanoparticles was performed using Cu(acac)2 precursor. Copper oxide nanoparticles were synthesized by combustion method. Identification of synthesized nanomaterials was performed using PXRD (powder X-ray diffraction) technique. The physical properties of synthesized materials were also evaluated using UV-Vis (ultraviolet-Visible), FT-IR analyzes. It also examined the size and morphology of the materials through the FESEM (scanning electron microscopy field) and TEM (transient electron microscopy). The energy band gap of nanomaterials was studied, with an optical band gap of about 4.58 eV. An electrochemical sensor was developed using nanoparticles that the sensor is capable of bisphenol A breaks down. The results of this sensor seem to be desirable and suggest that the oxidation peak potential of the bisphenol A at a surface of CuO nanoparticle modified carbon paste electrode (CuO/NPs/MCPE) appeared at 450 mV that was about 60 mV lower than the oxidation peak potential at the surface of the carbon paste electrode (CPE). At a best condition in voltammetric analysis, the oxidation peak current of bisphenol A showed linear dynamic range (in 0.1–400 μM) with a detection limit of 0.067 μM, using square wave voltammetry (SWV) method. The CuO/NPs/MCPE was successfully applied for the analysis of bisphenol A in food samples.
    Keywords: Combustion method_CuO nanoparticles_Sensor_Bisphenol A analysis_Modified electrode
  • Moussa Ouakki, Mouhsine Galai *, Mohammed Cherkaoui, El-Housseine Rifi, Zineb Hatim Pages 943-960
    The corrosion inhibition of mild steel in phosphoric acid solution containing a mineral compound based phosphate (apatite) was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy. Potentiodynamic polarization measurements reveal that the inhibition efficiency increased with the concentration of the apatite which appears to be a cathodic type inhibitor in the medium acid(H3PO4 2.0 M). Electrochemical impedance spectroscopy confirms this result, indeed the transfer resistance increases with apatite concentration. We note that the double layer capacitance decreases simultaneously suggesting the formation of an adsorbed layer on the mild steel surface. The inhibition mechanism has been elucidated by a thermodynamic study which showed that the film was formed by physi-sorption. The adsorption model obeys to the Langmuir adsorption isotherm. The parameters of activation energy was evaluated and discussed.
    Keywords: Corrosion inhibitor, Electrochemical methods, Apatite, Mild steel, Acid medium