فهرست مطالب

Analytical & Bioanalytical Electrochemistry
Volume:2 Issue: 1, Mar 2010

  • تاریخ انتشار: 1390/01/20
  • تعداد عناوین: 5
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  • Neelam Yugandhar Sreedhar, Puthalapattu Reddy Prasad, Sarvareddy Rajasekar Reddy Pages 1-12
    A differential pulse anodic stripping voltammetric method was based on the accumulation of Mo(VI) complex with phenylpiperazine dithiocarbamate on a hanging mercury drop electrode, followed by measurement of the current of the adsorbed complex. The effects of various parameters, such as reagent concentration, effect of pH of the medium, the accumulation potential, the accumulation time and the scan rate were investigated. Under the optimum conditions, a linear calibration graph was obtained in the concentration range of 0.01 to100 μg/mL with a correlation coefficient of 0.9994 and detection limit of 0.009 μg/mL. The effects of interference ions have been studied and it was found that the method is free from interferences of some common cations. The proposed method was applied for the determination of Mo(VI) in natural water and various food samples and the results showed good agreement with reported methods and the recoveries were in the range of 99.92 to 99.99 and 99.20 to 102.0 % respectively. The relative standard deviation for eight successive replicate analyses of Mo(VI) were 2.3% and 1.2%.
    Keywords: Differential pulse anodic stripping voltammetry (DPASV), Mo(VI), Water, Food samples
  • Electro-Oxidation and Determination of Amoxicillin in Drugs by a Copper Electrode
    H. Shafieyan, A. Rouhollahi Pages 13-23
  • Jahan Bakhsh Raoof, Reza Ojani, Ziya Mohammadpour Pages 24-35
    The homogeneous electrocatalytic oxidation of L-cysteine by 1,1′- Ferrocenedicarboxylic acid (FDC) as a redox mediator was studied in aqueous medium at the surface of a glassy carbon electrode (GCE) using cyclic voltammetry (CV), chronoamperometry and differential pulse voltammetry (DPV) methods. It was found that in the presence of FDC at pH 6.0, the mediated oxidation peak current of L-cysteine is maximum and the oxidation overpotential of L-cysteine decreases about 450 mV. The diffusion coefficient of L-cysteine and catalytic reaction rate constant were also determined using chronoamperometry. The experimental results showed that the electrocatalytic oxidation peak current of L-cysteine is proportional to the concentration of L-cysteine. The calibration plot for L-cysteine was found to be linear in the ranges of 6.0×10–5 M–2.0×10–3 M and 2.0×10–5 M–5.0×10–4 M by CV and DPV, respectively. The detection limits (S/N=3) were determined as 3.6×10–5 M and 9.8×10–6 M using CV and DPV methods, respectively. Finally, the proposed voltammetric method was used for the determination of L-cysteine in water samples by standard addition method.
    Keywords: L, Cysteine, 1, 1′ Ferrocenedicarboxylic acid, Homogeneous electrocatalysis, Voltammetric determination, Glassy carbon electrode
  • K. S. Beenakumari Pages 36-40
    Drinking water supply system is facing severe problems due to corrosion of iron pipes. The factors that affect pipeline corrosion include water composition, flow conditions and biological activity. The inhibitive effect of murraya koenigii leaf (curry leaf) extract on the corrosion of mild steel in drinking water was studied using weight loss, open circuit potential measurements and potentiodynamic polarization techniques. The results show that murraya koenigii leaf extract is effective in inhibiting corrosion of mild steel in drinking water system. As the concentration of the inhibitor in the medium increases, the inhibition efficiency increases. The percentage inhibitor efficiency calculated based on weight loss method is found to be above 95% when the medium contains 400ppm of inhibitor. The presence of murraya koenigii leaf (curry leaf) extract in drinking water improves the quality of water in addition to prevent the corrosion of iron pipes.
    Keywords: Mild steel, Corrosion, Inhibitor, Murraya koenigii leaf
  • Mohammad Mazloum, Ardakani, Hossein Rajabi, Hadi Beitollahi, Bi Bi Fatemah Mirjalili, Ali Akbari Pages 41-51
    A sensitive and selective electrochemical method for the determination of ascorbic acid (AA) was developed using a modified TiO2 nanoparticles carbon paste electrode. Cyclic voltammetry was used to investigate the redox properties of this modified electrode at various solution pH values and at various scan rates. This modified carbon paste electrode shows excellent electrocatalytic activity toward the oxidation of AA in a phosphate buffer solution (pH 8.0). The linear range of 0.3 to 20.0 μM and a detection limit of 1.43 × 10-7 M were observed in pH 8.0 phosphate buffer solution. Also, the modified electrode was employed for the determination of AA in the real samples such as AA ampoule using standard addition method.
    Keywords: Ascorbic acid, TiO2 Nanoparticles, Modified Carbon Paste Electrode, Electrocatalysis