فهرست مطالب

Analytical & Bioanalytical Electrochemistry
Volume:10 Issue: 1, Jan 2018

  • تاریخ انتشار: 1396/11/16
  • تعداد عناوین: 9
|
  • Hadi Mohammadi, Mohsen Khosravi, Seyed Mohammad Jafari Pages 1-17
    Lithium ion batteries are considered the most promising energy storage and conversion device candidates for use in future electric vehicle applications due to their ultrahigh energy density. In this study, a facile, ultrafast and green flame spray pyrolysis method was developed well to efficiently fabricate submicron-sized lithium cobaltite spheres from an aqueous spray solution of lithium nitrate and cobalt nitrate. Molar ratios of lithium: cobalt in the precursor solution was altered at three different levels, viz., 1: 1, 1.3: 1 and 1.7: 1. Then samples obtained under same conditions were calcined. Also, sample obtained with molar ratios of lithium: cobalt 1.7: 1, under different conditions atmosphere was calcined. The sample calcined in oxygen atmosphere with low flow was phase pure crystalline rhombohedral lithium cobalt oxide. Furthermore, this sample showed an acceptable performance as cathode active material of lithium ion battery. The rechargeable capacity was 162 mAh g-1 at 0.1 C and 101 mAh g-1 at 1 C and capacity retention of 84% after 50 cycles at this rate for this sample was observed.
    Keywords: Lithium ion batteries, Flame spray pyrolysis, Cathode active material, Lithium cobalt oxide, Layer structure
  • Parviz Norouzi*, Bagher Larijani, Mehdi Esmaeili Bidhendi, Mohammadamin Eshraghi, Mehrnaz Ebrahimi Pages 18-32

    A new electrochemical detection system was developed based on combination of a biosensor and Fast Fourier transform Admittance Voltammetry (FFTAV), which used for the sensitive detection of acrylamide. By effective self-assembling process, the biosensor was prepared of thiol functionalized single-stranded DNA (ssDNA) on gold nanoparticles, which deposited on a gold electrode decorated with polyaniline. The acrylamide has the ability to form a single complex with ssDNAs, which was linked on the biosensor surface, and changed the admittance of the electrode. Therefore, the concentration of acrylamide was detected directly by the change of admittance of the electrode. The biosensor was characterized by Scanning electron microscope-based (SEM), electrochemical impedance spectroscopy copy (EIS) and cyclic voltammetry. Under optimal conditions, the linear dynamic range of the acrylamide was 5.0×10-10 M to 2.0×10-7 M (r2 = 0.988) limits of detection of 5.0×10-11 M. The data showed that the electrochemical biosensor could detect acrylamide rapidly and accurately. Moreover, the proposed method demonstrated acceptable sensitivity and long-term stability.

    Keywords: Acrylamide, Electrochemical biosensor, Gold electrode modification, Fast Fourier transform Admittance Voltammetry
  • Mohamed Larouj, Hassane Lgaz, Rachid Salghi*, Houda Serrar, Said Boukhris, Shehdeh Jodeh Pages 33-51
    The corrosion inhibition efficiency of pyrimidothiazine compound, namely: 8-ethyl-3-hydroxy-4,6-dioxo-2-(p-tolyl)-4,6-dihydropyrimido [2,1-b][1,3] thiazine-7carbonitrile (EHDPTC), was evaluated in the system steel/1 M HCl. This compound is investigated experimentally using weight loss, potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results showed that the inhibition mechanism involves blockage of the steel surface by the inhibitor molecules by a Langmuir-type adsorption process and that the structure of molecule plays an important role in the inhibition efficiency of the synthesized inhibitor. The thermodynamic parameters of activation and adsorption have been calculated and discussed in detail. Furthermore, the quantum chemical parameters have been calculated and discussed in view of the results earlier reported.
    Keywords: Corrosion inhibition, Mild Steel, HCl, pyrimidothiazine, DFT
  • Hamid Reza Zare, Mehrjardi* Pages 52-63

    The complex cis-dioxo-bis[3-methoxy-2,2-dimethylpropanediamine] molybdenum(VI) (cis-[Mo(O)2L]) and toluidine blue O (TBO) are used for modification of carbon paste electrode (CPE). In order to study of the electrochemical behavior of ascorbic acid (AA) and dopamine (DA) at the surface of the modified CPEs, the differential pulse and cyclic voltammetric methods (DPV and CV) were used. These results reveal that by application of the modified CPE a peak resolution about 329 mV is obtained for AA and DA and the limits of detection (S/N=3) were 1×10−7 M and 4×10−7 M for DA and AA, respectively. Surface regeneration and the very easy preparation of the modified CPE together with the very good peak resolution and sub-micromolar detection limits designate the prepared CPE in this work appropriate for simultaneous voltammetric determination of DA and AA. The modified CPE was used successfully for recovery of the analytes in human plasma samples.

    Keywords: Molybdenum schiff base complex, Toluidine blue O, Modified electrode, Dopamine
  • S. B. Tanuja, B. E. Kumara Swamy*, K. Vasantakumar Pai* Pages 64-76
    The electrochemical studies of mesalazine was performed at sodium dodecyl sulfate modified carbon paste electrode by cyclic voltammetric technique in 0.2 M phosphate buffer solution at pH 7.2 with a scan rate 100 mV/s. Sodium dodecyl sulfate modified carbon paste electrode showed an enhanced current signal as compared to the bare carbon paste electrode. Electrochemical parameters like effect of pH, scan rate and different concentration of mesalazine were investigated at sodium dodecyl sulfate modified carbon paste electrode. The effects of scan rate study revealed that the overall electrode process was found to be adsorption controlled processes at sodium dodecyl sulfate modified carbon paste electrode. The detection limit of mesalazine was found to be 0.238 μM.
    Keywords: Mesalazine, Sodium dodecyl sulfate (SDS), Cyclic voltammetry (CV)
  • Mohammad Hasanzadeh *, Soodabeh Hassanpour, Arezoo Saadati Nahr, Nasrin Shadjou, Ahad Mokhtarzadeh, Soltanali Mahboob Pages 77-97
    The use of mesoporous nanomaterials as hosts for polymers production is a field of great interest, especially in the case of conducting polymers. Free-radical polymerization inside mesoporous silica has been investigated in order to open a route to functional polymer-silica composite materials with well-defined mesoporosity. In this report, proline monomers integrated with beta cyclodextrin were electropolymerized into amino functionalized mesoporous silica. The fabrication of poly-proline-amino functionalized magnetic mesoporous silica-beta cyclodextrin nanohybridon glassy carbon electrode was performed using one step electrodeposition regime. Field emission scanning electron microscopy was confirmed produced nano-hybrid material containing poly-proline into the pores of amino functionalized mesoporous silica which leads to increase of surface coverage of poly-proline. The results indicate that Poly-proline was successfully generated inside the pores of the amino functionalized MCM-41 and that the amine group was capable of protonating the polymer, producing poly-proline, the most conductive one, without the addition of another acid source during the polymerization step. The grafted amine groups also promoted a stronger interaction between inorganic matrix and proline than the observed in nano-encapsulated poly-proline, which resulted in high conductively. Therefore, it was evaluated some electrochemical aspects of the prepared nano-hybrid using cyclic voltammetry, differential pulse voltammetry and linear sweep voltammetry. Finally, the electroactivity of poly-proline-amino functionalized magnetic mesoporous silica-beta cyclodextrin nano-hybrid modified glassy carbon electrode towards detection and determination of some physiologically-relevant electroactive small molecules, was studied. Furthermore, it is demonstrated that the nano-coatings of polymers deposited on the mesopore walls have remarkably enhanced sensitivity and selectivity, as compared to that of bulk polymer resins. We believe that, due to facile functionalization and attractive textural properties, the mesoporous polymer-silica composite materials are very useful for biomedical applications.
    Keywords: Mesoporous silica, Magnetic nanoparticle, Nanotechnology, Electropolymerization, Proline, Beta cyclodextrin
  • Chandrabhan Verma, M. A. Quraishi, Eno E. Ebenso* Pages 98-110
    The adsorption behavior of three purine based chemical medicines (drugs) namely, 2-amino-9-((2-hydroxyethoxy)methyl)-3H-purin-6(9H)-one (Acyclovir; Acy), ((1S,4R)-4-(2-amino-6-(cyclopropylamino)-9H-purin-9-yl)cyclopent-2-en-1-yl)methanol (Abacavir; Aba) and (R)-(((1-(6-amino-9H-purin-9-yl)propan-2-yl)oxy)methyl)phosphonic acid (Tenofovir; Ten) on mild steel corrosion in acidic solution has been investigated using DFT based quantum chemical calculations. An attempt has been made to established correlation between experimentally determined inhibition efficiency and DFT based quantum chemical calculations. Several computational parameters such as energies of highest occupied and lowest unoccupied frontier molecular orbitals (EHOMO and ELUMO), energy band gap (ΔE), electronegativity (χ), global harness (η) and global softness (σ), fraction of electron transfer (ΔN), and dipole moment (μ) were derived in order to describe the relative adsorption tendency of these drugs on the mild steel surface. Among the tested drugs, abacavir exhibited the maximum adsorption tendency. The adsorption tendency of these drugs follows the order: abacavir>acyclovir>tenofovir. The DFT based quantum chemical calculations was carried out for neutral as well as protonated forms of the drug molecules.
    Keywords: DFT study, Corrosion inhibition, Frontier molecular orbitals, Drug molecules, Adsorption behavior, Theoretical parameters
  • Nadia Dkhireche, Mouhsine Galai, Younes El Kacimi*, Mohamed Rbaa, Moussa Ouakki, Brahim Lakhrissi, Mohammed Ebn Touhami Pages 111-135
    Abstract- Two newly synthesised Quinoline derivatives, namely 5-((2-(4-dimethylamino)phenyl-1H-benzo[d]imidazol-1-yl)methyl)quinolin-8-ol (Q-N(CH3)2) and 5-((2-(4-nitrophenyl)-1H-benzo[d]imidazol-1-yl)methyl)quinolin-8-ol (Q-NO2) were studied as inhibitors for the corrosion of mild steel in 0.5 M sulphuric acid solution has been examined and characterized by weight loss, polarization and electrochemical impedance spectroscopy (EIS). The experimental results reveal that the organic compound has a good inhibiting effect on the mild steel in 0.5 M H2SO4 solution. The protection efficiency increases with increasing inhibitor concentration, but the temperature has hardly effect on the inhibition efficiency of Q-N(CH3)2 and Q-NO2. The adsorption of the inhibitors on the surface of mild steel in a 0.5 M H2SO4 solution was found to obey Langmuir’s adsorption isotherm. Thermodynamic data clearly show that the adsorption mechanism of Q-N(CH3)2 and Q-NO2 on mild steel surface in 0.5 M H2SO4 solution is mainly electrostatic-adsorption. Potentiodynamic polarization studies have shown that Quinoline derivatives acts as a mixed type of inhibitor. Data obtained from EIS studies were analyzed to model inhibition process through appropriate equivalent circuit model. The Scanning Electron Microscope (SEM) images of the corrosion product confirmed the protection offered by the extract on the surface of the metal immersed in both media.
    Keywords: Quinoline derivatives, Corrosion inhibition, Mild steel, Sulphuric Acid, EIS
  • Nooshin Mirzanasiri, Morteza Hosseini*, Bagher Larijani, Hamid Rashedi Pages 147-160
    Levedopa was sensitively determined based on electrogenerated chemiluminescence (ECL) mechanism through enhancing the weak ECL of electro-oxidized luminal in presence of levodopa, on a multiwall carbon nanotubes (MWCNTs)-modified electrode. Under optimal conditions, the relative ECL emission/levodopa concentration plot was found to be linear from 1.0×10-9 to 1.7×10-7 M and a detection limit of 6.7×10-10 M was recorded. The modified electrode was found applicable to the analysis of levodopa in urine samples.
    Keywords: Multiwalled carbon nanotube, Electrochemiluminescense, Gold electrode, Luminol, Levodopa