فهرست مطالب

Analytical & Bioanalytical Electrochemistry - Volume:11 Issue: 8, 2019
  • Volume:11 Issue: 8, 2019
  • تاریخ انتشار: 1398/08/01
  • تعداد عناوین: 10
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  • Asieh Hosseini, Esmail Sohouli, Maryam Gholami, Ali Sobhani*, Seyed Ali Mirhosseini Pages 996-1008

    CoFe2O4 nanostructures composed of spherical-like were obtained by sol-gel method with glucose as template and combine with MWCNT and composed CoFe2O4-MWCNT heterostructure. The crystal Structure, phase composition, morphology and magnetic properties of CoFe2O4/MWCNT heterostructure were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometers (VSM), A pure phase of well crystallized CoFe2O4 nanostructures, with average size of 60 nm, could be readily synthesized at present glucose. The modified glassy carbon (GC) electrode with CoFe2O4-MWCNT heterostructure was used to determine the ciprofloxacin concentration. A cyclic voltammetric technique was used for comparison between the unmodified and modified electrodes. The fabricated modified electrode shows linear response for detection of ciprofloxacin at two linear range of 0.1-1 μM and 1-30 μM with a detection limit of 0.036 μM.

    Keywords: Ciprofloxacin, Electrochemical Determination, Glassy Carbon Electrode, CoFe2O4, MWCNT, Sol-gel method
  • Neda Faizbakhsh, Ebrahim Naghian, Maryam Akbari, Mohammad Vosoughifar* Pages 1009-1019

    A novel and facile approach for preparing BaFe12O19/Fe3O4 nanostructures was developed utilizing the ultrasonic assisted method. The BaFe12O19/Fe3O4 nanostructures were studied by FT-IR spectroscopy, Transmission electron microscopy (TEM), and X-ray diffraction (XRD). XRD results showed that the BaFe12O19/Fe3O4 nanostructures are in good crystalline with average size of 18 nm. The carbon paste electrode modified with iron oxide nanoparticles were used as an electrochemical sensor for determination of sildenafil in an aqueous medium. The electrochemical properties of the prepared sensor was evaluated by the cyclic voltammetric and electrochemical impedance spectrometry techniques. The relationship between the current and concentration of sildenafil obtained using differential pulse voltammetry was linear in the 1-100 μM region and limit of detection was 0.1 μM.

    Keywords: BaFe12O19, Fe3O4, Nanostructures, Ultrasonic assisted method, Sildenafil, Electrochemical sensor
  • Seyed Omid Gashti, Arash Fattah*, Zahra Masoomi Pages 1020-1031

    The present work has studied the effect of sodium fluoride on properties of plasma electrolytic oxidation (PEO) coatings. PEO coatings were formed on 6061 Al alloy in aluminate based electrolytes with different sodium fluoride concentrations. The results indicated that addition of sodium fluoride to the electrolyte prepared ceramic coating with high quality and therefore improved the corrosion resistance in 3.5 wt% NaCl solution. Scanning electron microscopy (SEM) images were used to examine the cross sectional and surface morphology of the coatings. The corrosion behavior of the PEO coatings were evaluated using electrochemical impedance spectroscopy (EIS). The corrosion behavior of the coatings improved by adding 1 g/L sodium fluoride into the electrolyte, but the corrosion resistance of the coatings decreased while adding more than 1 g/L sodium fluoride in electrolyte solution. The prepared sample in the electrolyte with 1 g/L sodium fluoride showed the best morphology with the least porosity and more corrosion resistance compared with other coatings.

    Keywords: Sodium aluminate, Sodium fluoride, 6061 aluminum alloy, Plasma electrolytic oxidation
  • Nordine Errahmany, Mohamed Rbaa*, Abdellatif Tazouti, EL Hassan EL Kafssaoui, Brahim Lakhrissi, Rachid Touir, Mohamed Ebn Touhami Pages 1032-1052

    Two substituted quinoxaline derivatives, namely diethyl 2,2-(2,3-dioxo-2,3- dihydroquinoxaline-1,4-diyl)diacetate (QX-H) and diethyl 2,2-(6-methyl-2,3-dioxo-2,3- dihydroquinoxaline-1,4-diyl)diacetate (QX-CH3), were tested as a corrosion inhibitor for mild steel in 1.0 M HCl solution using weight loss, Tafel polarization and electrochemical impedance spectroscopy (EIS). The experimental results reveal that the studied compounds have good inhibiting effects of mild steel corrosion in 1.0 M HCl medium. It is found that their inhibition efficiency increases with their concentration to reach a maximum at 10-3 M and they are acting as mixed type inhibitors. So, the inhibition efficiency was increased with inhibitor concentration in the order QX-CH3>QX-H which depended on their molecular structures. It has been determined that the adsorption of these compounds on mild steel surface complies with the Langmuir adsorption isotherm. However, in order to get information on bonding mechanism of mild steel surface/ inhibitors/1.0 M HCl solution system, the corrosion protection was also investigated by Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Spectroscopy (EDS). Finally, the experimental obtained results were confirmed by the theoretical study.

    Keywords: Quinoxaline derivatives, Mild steel, HCl, Corrosion inhibition, Electrochemical techniques, Weight loss, SEM, EDS analysis
  • Negar Rajabi, Mahboubeh Masrournia*, Mohamadreza Abedi Pages 1057-1069

    In this study, the synthetic ligand of ortho-phenylenediamine (C22H22N4O4) was used as an ionophore in the design and manufacture of Gd(III) ion selective carbon paste electrode. The D-optimal Mixture Design was used to investigate the effects of independent parameters and their correlations, for evaluating and optimizing of the components of the Gd(III) carbon paste electrodes. The Design-Expert (Plackett-Burman Design) software package Minitab ver. 17.0 optimized the composition of the membrane percentage of the proposed sensor. The experimental design method reduces of number of experiments and saving time and cost. Also consider simultaneously effect of factors on optimal condition, study non-linear relations and the interactions between factors is possible. The optimal components of the membrane included graphite powder 60.00%, paraffin oil 30.00%, ionophore 8.00%, and multiwall carbon nanotubes 2.00 %. Ion selective electrode show the Nernst slope of 19.08 mV/decade at a concentration range of 1.0×10-2 to 1.0×1.0-7 mol L-1,
    with the detection limit of 2.14±10-8 mol L-1. The desired electrode has a response time of less than 15 seconds and relatively good lifetime in the pH 5-9 range. It can also be used in potentiometric titration of Gd(III) by EDTA.

    Keywords: Gd(III), Ortho phenylenediamine, Experimental design, Ion selective electrode, Multi-walled carbon nanotubes
  • Tadesse Gebregiyorgis, MeridTessema, Shimelis Admassie, Gebremariam Birhanu, Ayenew Ashenef* Pages 1070-1086

    A novel stripping square wave voltammetric method has been developed for the determination of uric acid (UA) in untreated human urine. In this study, we introduced a new electrode based on iron(III) doped zeolite graphite powder composite (GPC) modified glassy carbon electrode (GCE). Iron(III) loaded in zeolite matrix can increase anodic peak current by adsorption of uric acid compound on the electrode surface. The results indicated that Fe+3 Y/GPC modified GCE facilitate the determination of uric acid with good sensitivity and reproducibility. The optimum conditions selected for the determination of uric acid using square wave voltammetry were: pulse amplitude 40 mV, Scan rate100 mV/s, accumulation time 30 s, and accumulation potential +100 mV, pH of supporting electrolyte (pH)=7. Under these optimum conditions, the oxidation peak current of UA increased linearly with concentration in the range of 2.0×10−6 to 8.0×10-5 mol L−1 with linear equation, correlation coefficient (R2) and detection limit (based on the formula LoD=3δ/m) of Ipa (μA)=0.1952–0.3252 C (μM), 0.99903 and 2.32×10-7 mol L-1, respectively.

    Keywords: Stripping square wave voltammetry, Uric acid, Zeolite, Modified glassy carbon electrode, Urine, Graphite powder
  • Hamid Reza Naderi, Saeid Pourmasoud, Vahid Ameri, Mohammad Eghbali* Pages 1087-1099

    Flower like ytterbium molybdate nanopowders were prepared via the fast and easy rout. Pure structure of flower like ytterbium molybdate nanopowders was examined through some techniques including, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), Energy dispersive X-ray microanalysis (EDX). Addition to image SEM revealed flower like ytterbium molybdate nanopowders that composite from nanoplate with 5 nm thickness and length of 600 nm. Electrochemical efficiency of ytterbium molybdate nanostructure synthesized on a steel plate as a main material for a capacitor electrode in 3M KCl medium was studied using galvanostatic charge/discharge, cyclic voltammetry and electrochemical impedance spectroscopy techniques. The evaluations on Ytterbium molybdate-based electrodes showed that these materials have a specific capacitance (SC) of 318 F g-1 at a scan rate of 2 mV s-1, an energy density (ED) of 24.3 W h kg-1, and a high rate capability. Assessment continual evaluations of cyclic voltammetry making use of ytterbium molybdate-based electrodes confirmed that the electrodes have a potential to keep up to 96.1% of their initial SC after 4000 cycles. As far as we concern the novelty of this work is making use of ytterbium molybdate as electrode materials to be used in supercapacitors. Our findings show an agreement with remarkable features of ytterbium molybdate for such application.

    Keywords: Ytterbium molybdate, Nanopowders, Precipitation method, Flower like, Supercapacitors
  • G. Venkataprasad, T. Madhusudana Reddy* T. Venu Gopal, P. Shaikshavali, P. Gopal Pages 1100-1116

    A facile, sensitive and selective electrochemical sensor was fabricated based on electropolymerization of Evan’s blue (Eb) (Poly(Eb)) on the carbon paste electrode (CPE) followed by drop casting of graphene (GR) onto the Poly(Eb)/CPE. The electrochemical behaviour of dopamine (DA) at the surface of GR/Poly(Eb)/CPE was studied. Moreover, the surface morphology of various types of modified electrodes was characterised by electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The proposed electrochemical sensor has successfully facilitated the simultaneous resolution of DA in presence of uric acid (UA) and folic acid (FA). A good linear relationship was observed for the detection of DA in the range between 5-110 μM, with the lower detection limit of 6.52 μM. The analytical application of GR/Poly(Eb)/CPE was also studied towards the detection of dopamine in real sample analysis with good recovery results

    Keywords: Electrochemical sensor, Simultaneous resolution, Graphene, Dopamine, Evan’s blue, Folic acid, Uric acid
  • Levent Özcan*, Esra Efe Pages 1117-1128

    Paracetamol is one of the most commonly used analgesics and its overdose causes toxicity. Therefore investigation of simple and effective techniques to determine paracetamol in the metabolism is very important. In this study TiO2 modified Fluorine-doped Tin Oxide (FTO) electrodes were investigated for photoelectrochemical determination of paracetamol and parameters affecting the photoelectrochemical signal of the electrodes were investigated. Initially, FTO electrodes were modified by adsorbing two commercial TiO2 (Merck and Degussa P25) and used for paracetamol determination. Higher photocurrent value was obtained by Degussa P25 (DegTiO2) modified electrode with respect to Merck one, therefore the optimization of the other analytical parameters was carried out with DegTiO2 modified electrodes. The effect of DegTiO2 amount on the FTO, solution pH, and applied voltage on the photocurrent values for paracetamol oxidation was studied. The electrode prepared as four-layer of DegTiO2 on the FTO surface showed the highest photocurrent value at 0.30 V and at pH 5.0. The photocurrent values are linear from 0.25 μM to 10 μM concentration of paracetamol and the limit of detection of paracetamol concentration is 0.07 μM. These results show that DegTiO2 modified FTO could be used as an effective and sensitive photoelectrochemical paracetamol sensor

    Keywords: Paracetamol determination, Acetaminophen, Photoelectrochemical Sensor, TiO2, Fluorine-Doped Tin Oxide Electrode (FTO), Modified Electrode
  • Nacer Hechiche, Dalila Boughrara, Abdelaziz Kadri, Nacera Dahmani, Nassima Benbrahim Pages 1129-1147

    Artemisia herba-alba essential oil extract was investigated as green inhibitor for aluminum corrosion in 1 M HCl solution. The chemical analysis obtained by gas chromatography and gas chromatography–mass spectrometry, revealed 68 components. The inhibition efficiency was determined by weight loss measurements, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscope. The results revealed an increase of inhibition efficiency by maximum 92% trough increasing the oil concentration to 3 g/L at 333 K. The oil compounds adsorb by physisorption, follow Langmuir adsorption isotherm and act as mixed type inhibitors. The EIS results confirmed the adsorption mechanism process and the SEM observations

    Keywords: Aluminum, Artemisia herba-alba, EIS, SEM, Acid inhibition