Comparison of Gold and Platinum Electrode Responses in Activated Sludge

1993 ◽  
Vol 28 (11-12) ◽  
pp. 473-480
Author(s):  
A. Heduit ◽  
B. Martin ◽  
I. Duchamp ◽  
D. R. Thevenot
Keyword(s):  
Electron Transfer ◽  
Activated Sludge ◽  
Gold Electrode ◽  
Platinum Electrode ◽  
Electrochemical Determination ◽  
Exchange Current ◽  
Experimental Conditions ◽  
Equilibrium Exchange ◽  
Prolonged Contact ◽  
Current Densities

Gold and platinum were compared to ascertain how they expressed a stabilized potential in activated sludge. The comparison was based on electrochemical determination of the electron transfer rate (i.e. equilibrium exchange current density) and recording of potentials against time. When both metals are treated in the same way, platinum gives equilibrium exchange current densities approx. 10 times higher than gold, both in aerated activated sludge and in treated water. For platinum, the equilibrium exchange current densities range from 0.1 to 0.25 µA/cm2 immediately after polishing and decrease during prolonged contact with activated sludge subjected to alternating aeration/anoxia sequences. The lower kinetics of electron transfer on gold go together with significant differences in response:- In an aerobic medium a gold electrode potential is lower than that of a platinum electrode. In a strongly anaerobic medium, the reverse is true. Consequently, the amplitude of the potential variation between aerobic and anaerobic media is smaller for gold than for platinum. Under our experimental conditions this amplitude was approx 350 mV for gold and 850 mV for platinum.- The slopes of the linear relationships between potential and pH or potential and the logarithm of the dissolved oxygen concentration are two or three times greater for platinum than for gold. Although the values obtained with platinum electrodes cannot represent a veritable equilibrium state, the platinum electrode zero-current potential would seem to be far more sensitive to variations in the medium than that of the gold electrode; it is, therefore, more suitable for use in activated sludge.

scholarly journals A study of the electrochemical activity of some macrolide antibiotics on a gold electrode in a neutral electrolyte

2007 ◽  
Vol 72 (12) ◽  
pp. 1427-1436 ◽  
Author(s):  
Milka Avramov-Ivic ◽  
Slobodan Petrovic ◽  
D.Z. Mijin
Keyword(s):  
Gold Electrode ◽  
Structural Changes ◽  
Linear Sweep Voltammetry ◽  
Electrochemical Determination ◽  
Electrochemical Reactions ◽  
Cathodic Peak ◽  
Experimental Conditions ◽  
Neutral Electrolyte ◽  
Anodic Reactions

The aim of the present study is to present the different reactivity of azithromycin and clarithromycin (pure and commercial) at a gold electrode in neutral electrolyte using cyclic linear sweep voltammetry under the same experimental conditions. A gold electrode was successfully used for the electrochemical qualitative and quantitative determination of azithromycin dihydrate and azithromycin from capsules (Hemomycin?) and for the separation of azithromycin from one of the excipients, lactose monohydrate. The good catalytically activity of the gold electrode was employed only for the qualitative electrochemical determination of pure clarithromycin by appearance of one cathodic and four anodic reactions, which enabled structural changes in this molecule during electrochemical reactions to be studied. Commercial clarithromycin, Clathrocyn? was qualitative determined by one reproducible anodic reaction. The activity of one of the excipients, Avicel, observed as a cathodic peak at different potential from the cathodic peak obtained with pure clarithromicin was used for the determination of its presence in Clathrocyn? tablets. FTIR Analysis showed the apparent changes in structure of pure clarithromycin, as well as in the molecule of clarithromycin in Clathrocyn? tablets. HPLC Analysis showed a significant decrease in the concentration of azithromycin, Hemomycin? clarithromycin and Clathrocyn? after the electrochemical reactions.

scholarly journals Electrochemical determination of sertraline in pharmaceutical formulation and serum using a gold electrode in a pH 8.4 bicarbonate solution

2021 ◽  
Vol 152 (2) ◽  
pp. 185-192
Author(s):  
Jelena Lović ◽  
Jelena Lađarević ◽  
Nemanja Trišović ◽  
Filip Andrić ◽  
Aleksandar Mladenović ◽  
...  
Keyword(s):  
Gold Electrode ◽  
Electrochemical Determination ◽  
Pharmaceutical Formulation

scholarly journals Label-Free Electrochemical Test of Protease Interaction with a Peptide Substrate Modified Gold Electrode

Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 199
Author(s):  
Anna Wcisło ◽  
Izabela Małuch ◽  
Paweł Niedziałkowski ◽  
Tadeusz Ossowski ◽  
Adam Prahl
Keyword(s):  
Gold Electrode ◽  
High Selectivity ◽  
Electrode Materials ◽  
Electrochemical Biosensors ◽  
Electrochemical Characteristics ◽  
Label Free ◽  
Peptide Substrate ◽  
Electrochemical Test ◽  
Experimental Conditions ◽  
Spectrofluorimetric Method

Efficient deposition of biomolecules on the surface, maintaining their full activity and stability, is a most significant factor in biosensor construction. For this reason, more and more research is focused on the development of electrochemical biosensors that have the ability to electrically detect adsorbed molecules on electrode surface with high selectivity and sensitivity. The presented research aims to develop an efficient methodology that allows quantification of processes related to the evaluation of enzyme activity (proprotein convertase) using electrochemical methods. In this study we used impedance spectroscopy to investigate the immobilization of peptide substrate (Arg-Val-Arg-Arg) modified with 11-mercaptoundecanoic acid on the surface of gold electrode. Both the synthesis of the peptide substrate as well as the full electrochemical characteristics of the obtained electrode materials have been described. Experimental conditions, including concentration of peptide substrate immobilization, modification time, linker, and the presence of additional blocking groups have been optimized. The main advantages of the described method is that it makes it possible to observe the peptide substrate–enzyme interaction without the need to use fluorescent labels. This also allows observation of this interaction at a very low concentration. Both of these factors make this new technique competitive with the standard spectrofluorimetric method.

scholarly journals Estimation of the exchange current density and comparative analysis of morphology of electrochemically produced lead and zinc deposits

2017 ◽  
Vol 82 (5) ◽  
pp. 539-550
Author(s):  
Nebojsa Nikolic ◽  
Predrag Zivkovic ◽  
Goran Brankovic ◽  
Miomir Pavlovic
Keyword(s):  
Current Density ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Diffusion Current ◽  
Electron Microscopic ◽  
Zinc Electrodeposition ◽  
Lead And Zinc ◽  
Current Densities ◽  
Limiting Diffusion Current ◽  
Zinc Deposits

The processes of lead and zinc electrodeposition from the very dilute electrolytes were compared by the analysis of polarization characteristics and by the scanning electron microscopic (SEM) analysis of the morphology of the deposits obtained in the galvanostatic regime of electrolysis. The exchange current densities for lead and zinc were estimated by comparison of experimentally obtained polarization curves with the simulated ones obtained for the different the exchange current density to the limiting diffusion current density ratios. Using this way for the estimation of the exchange current density, it is shown that the exchange current density for Pb was more than 1300 times higher than the one for Zn. In this way, it is confirmed that the Pb electrodeposition processes are considerably faster than the Zn electrodeposition processes. The difference in the rate of electrochemical processes was confirmed by a comparison of morphologies of lead and zinc deposits obtained at current densities which corresponded to 0.25 and 0.50 values of the limiting diffusion current densities.

scholarly journals Simultaneous electrochemical determination of acetaminophen and metoclopramide at electrochemically pre-treated disposable graphite pencil electrode

2016 ◽  
Vol 6 (3) ◽  
pp. 265 ◽  
Author(s):  
Shreekant M Patil ◽  
Vijay P Pattar ◽  
Sharanappa T Nandibewoor
Keyword(s):  
Simultaneous Determination ◽  
Differential Pulse ◽  
Electrochemical Determination ◽  
Experimental Conditions ◽  
Positive Direction ◽  
Oxidation Potentials ◽  
Voltammetric Behavior ◽  
Pulse Voltammetry ◽  
Apparent Shift

<p class="PaperAbstract"><span lang="EN-US">A sensitive and economic voltammetric method was developed for the simultaneous determination of acetaminophen (AMP) and metoclopramide (MCP) using pre-treated graphite pencil electrode (PTGPE). Compared to a graphite pencil electrode, the pre-treated electrode showed an apparent shift of the oxidation potentials in the positive direction and a notable enhancement in the current responses for both AMP and MCP. Cyclic voltammetry (CV) was used to study the voltammetric behavior of the drugs, while differential pulse voltammetry (DPV) was used to determine AMP and MCP simulta­neously. The dependence of the current on scan rate, pH and concentration was investi­gated to boost the experimental conditions for simultaneous determination. The calibra­tion curves were obtained over the range of 0.1</span><span lang="EN-US">×</span><span lang="EN-US">10<sup>-7</sup> to 1.1</span><span lang="EN-US">×</span><span lang="EN-US">10<sup>-7</sup> M, the concentration of each of both the drugs was varied by keeping the other constant, and achieved lower detection limit of 3.25 nM for AMP and 1.16 nM for MCP. The developed method was found to be selective and rapid for the simultaneous determination of AMP and MCP. The proposed method was applied simultaneously in real samples and pharmaceutical samples, with satisfactory results.</span></p>

Electron transfer between ferrocene and hexacyanoferrate(III) across the water/1,2-dichloroethane interface

1988 ◽  
Vol 53 (5) ◽  
pp. 903-911 ◽  
Author(s):  
Josef Hanzlík ◽  
Jan Hovorka ◽  
Zdeněk Samec ◽  
Štefan Toma
Keyword(s):  
Electron Transfer ◽  
Aqueous Phase ◽  
Rate Constant ◽  
Potential Range ◽  
Ion Transfer ◽  
Potential Sweep ◽  
Experimental Conditions ◽  
Chemical Decomposition ◽  
Kinetics Of

Kinetics of electron transfer between ferrocene or its derivative (1,1'-diethyl- or 1,1'-distearoylferrocene) in dichloroethane and hexacyanoferrate(III) in water was studied by means of convolution potential sweep voltammetry. Within the accessible range of experimental conditions no effect of either the potential or concentrations of reactants on the rate constant of electron transfer from the organic to the aqueous phase (ko→w = 1 . 10-7 m4 mol-1 s-1) was observed. Electron transfer was shown to occur far from the potential range, in which the ferricenium ion transfer can take place. However, the reaction was complicated by the chemical decomposition of ferricenium in dichloroethane (k = 0·346 s-1).

Electron Transfer in Electro-Oxidation of Amoxicillin Using Platinum Electrode and Platinum Modified Cobalt Electrodes

2021 ◽  
Vol 874 ◽  
pp. 155-164
Author(s):  
Herlina ◽  
Muhammad Ali Zulfikar ◽  
Buchari
Keyword(s):  
Electron Transfer ◽  
Oxidation Process ◽  
Platinum Electrode ◽  
Linear Sweep Voltammetry ◽  
Pharmaceutical Product ◽  
Electrochemical Methods ◽  
Linear Sweep ◽  
Low Concentrations ◽  
Electro Oxidation ◽  
Continuous Use

Recently, the increased use of antibiotics in the environment has been studied and one of them is amoxicillin. Amoxicillin (AMX) is a pharmaceutical product that can become waste due to the continuous use and released into the ecosystem even at low concentrations. The electro-oxidation process is one of the electrochemical methods used to destruct the existence of antibiotics because the process is relatively fast and inexpensive. Platinum electrode and platinum modified cobalt electrodes are used for amoxicillin electro-oxidation at the pH of 2 - 7. The range of this amoxicillin's pH was achieved by the pKa's values of the amoxicillin and measured using a UV/Vis spectrophotometer. Electron transfer during the amoxicillin electro-oxidation process with these electrodes is measured by linear sweep voltammetry. The results obtained during the electro-oxidation process showed that electron transfer of amoxicillin was 1, with a Nernstian factor of 0.0521 V/pH for platinum electrode and platinum modified cobalt electrodes, Pt/Co(OH)2 and Pt/Co respectively with values of 0.0506 V/pH and 0.0673 V/pH.

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