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This work aims to develop a new abase anode of organic molecule to study the electro-oxidation of methanol, in an alkaline solution with a carbon paste electrode modified by Ethylene-diamine tetra acetic acid disodium salt dehydrate EDTA-CPE, by cyclic voltammetry, measurements of ‘impedance and chronoemperometry. Radiography carried out morphological characterizations by microscopic electronic transmission (MET). The organic molecule has been found to have better catalytic activity for the oxidation of methanol; they are simple, cheaper and stable. Keywords: Methanol fuel cell; electro catalysis; modified electrodes; EDTA, catalyst, Chronoamperometry, impedance spectroscopy.

This work aims to study the electrolytic oxidation of ethanol in alkaline solution by a carbon paste electrode modified with natural phosphate and cobalt (Co-NP/CPE). The electrodes were obtained by depositing the cobalt on carbon-NP substrates by electrodeposition, using potentiostatic and galvanostatic techniques. Morphological characterisation by optical microscopy techniques shows that the Co is well dispersed with the presence of NP particles on the surface of the electrode. The study of the electrode behaviour by voltammetric techniques exhibits a catalytic effect leading to a better result regarding the oxidation of ethanol. Compared to CPE-NP, the cobalt-modified CPE-NP electrode exhibits high electrolytic activity for ethanol oxidation. This work is licensed under a Creative Commons Attribution 4.0 International License., Cilj ovog rada bio je ispitati elektrolitičku oksidaciju etanola u alkalnoj otopini pomoću elektrode od ugljikove paste modificirane prirodnim fosfatom i kobaltom (Co-NP/CPE). Elektrode su dobivene elektrodepozicijom kobalta na ugljik-NP supstrat, primjenom potenciostatskih i galvanostatskih tehnika. Morfološka karakterizacija modificiranih elektroda provedena je optičkom mikroskopijom koja je pokazala dobru raspršenost kobalta te prisutnost NP čestica na površini elektrode. Usporedbom dobivenih voltamograma vidljivo je da navedena elektroda pokazuje katalitički učinak što dovodi do bolje oksidacije etanola. U usporedbi s nemodificiranom CPE-NP elektrodom, elektroda modificirana kobaltom pokazuje visoku elektrolitičku aktivnost za oksidaciju etanola. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna.

In this work, an electrochemical sensor was prepared by modifying a carbon paste with the organic molecule of 2-benzimidazolethiol (CPE/OM) by mixing methods (by combination of the organic molecules and the carbon electrode). The sensor was tested for detection of lead ions in an aqueous solution. All reactions studied took place on the modified electrode surface, the place of contact between the electrode and the electrolytic medium. For this reason, the electrochemical properties of the CPE/OM, including cyclic voltammetry and square wave voltammetry techniques, were used. Cyclic voltammetry studies have indicated the reaction involved. The determination of lead was carried out utilising the voltammetric technique at the surface of the modified electrode, and the correlation between the current of peak oxidation and the concentration of this ion showed a detection limit (DL) of 3.43 ∙ 10–6 mol l–1. The experimental results proved that the carbon paste electrode modified with 2-benzimidazolethiol had high sensitivity toward lead ions and a wide linearity range. This work is licensed under a Creative Commons Attribution 4.0 International License., U ovom je radu pripravljen elektrokemijski senzor (CPE/OM) modificiranjem ugljikove paste s organskom molekulom 2-benzimidazoletiolom. Ispitana je primjenjivost senzora za detekciju iona olova u vodenoj otopini. Sve proučavane reakcije odvijale su se na modificiranoj površini elektrode, tj. na mjestu kontakta elektrode i otopine. Stoga su upotrijebljene ciklička voltametrija i voltametrija kvadratnog vala. Ciklička voltametrija je pokazale koje se reakcije odvijaju. Određivanje olova provedeno je voltametrijski na površini modificirane elektrode, uz granicu detekcije (DL) od 3,43 ∙ 10–6 mol l–1. Eksperimentalni rezultati pokazali su da elektroda modificirana 2-benzimidazoletiolom ima visoku osjetljivost prema ionima olova te veliko područje linearnosti. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna.

The aim of this work is to combine two methods for removing nitrate ions from concentrated aqueous solutions. This involves chelating and then reducing NO3− by EDTE modified carbon paste electrode (EDTA-CPE). We find that in the absence of EDTA on the carbon paste electrode surface, the nitrate reduction is almost impossible. The reduction of nitrate ions was invested on the surface of the EDTA-CPE, the cyclic voltammograms recorded in electrolytic medium 0.1 M KCl, shows two reduction peaks, the first at −0.2 V, attributed to the reduction of nitrite ions (NO2−) and the second one at 0.8 V which corresponds to the reduction of nitrate to nitrite ions. Keywords: Nitrate, Electrochemical reduction, EDTA, Chelating, Modified electrode

Mesoporous Ni/Al-Layered double hydroxide (Ni/Al-LDH) surface has been assembled with metal oxides (Fe2O3). The obtained nanocomposite structure has been tested as probe electrode for the electrochemical detection of mercury Hg (II) in solution. An electrochemical study of the CPE-Fe2O3@Ni/Al-LDH modified electrode is achieved in the presence of mercury ions. The recorded cyclic voltammogram has shown a reversible process corresponding to the Hg (II)/Hg couple. These results demonstrate the potential role of nanoparticles associated with mesoporous material in developing strategies for simple and fast detection of metal ions in solution with detection limited 46 nM.

A simple and efficient system has been described for selective detection of p-nitrophenol. Herein α-Fe2O3@MgAl-CO3-Layered double hydroxides nanocomposite was coated on carbon-paste electrode (CPE) to electrochemical determination of p-nitrophenol via voltammetric analysis. The α-Fe2O3@MgAl-CO3-LDH nanocomposite was synthesized by coprecipitation method and characterized by various physical–chemical techniques of analyses such as XRD, TG-dTG, IR-TF, BET and SEM/EDX. As a result, this novel methodology was effectively implemented to p-nitrophenol detection with the lowest detection limit (4, 98 μM).

The objective of this work is the standardization of the operating parameters of the carbon graphite paste (CPE) electrode modified by di-sodium ethylenediamine tetraacetic acid (EDTA) for the detection and quantification of Pb(II). The prepared electrode was used for the simultaneous detection of Pb (II), Co (II) and Cu (II) in drinking water. It is shown that the electrode is linear in the concentration range of 0.302 mmol/ L to 1.812 mmol/ L for Pb(II) under optimal chemical and electrochemical conditions that have been previously determined. We found that Pb(II), Co(II) and Cu(II) are not affected. The sensor surface was studied by Energy Dispersive Spectrometry (EDX) coupled with Scanning Electron Microscope (SEM). The analysis of the surface area of CPE-10% EDTA by SEM shows the presence of the complexes formed by the association of EDTA with Pb(II) ions. The Square Wave Voltammetry showed that the CPE modified by 10% of the EDTA is better than the CPEs modified by 30% and 50% of the EDTA. The Square Wave Voltammetry of the electrode modified by EDTA in the presence of lead showed that the latter is characterized by two oxidation peaks (Epa1 = -0.7 V and Epa2 = -0.53 V) and a peak corresponds to the reduction in ionic lead that appeared at Epa3 = -0.398 V. The detection limit of Pb(II) obtained by SWV in the electrolyte solution is 2.33 × 10−9 mol / L (LD, 3 s) and the quantification limit (LQ, 10 s) is 7.77 × 10−9 mol / L with coefficients of determination equal to 0.978.

The carbon paste electrode (CPE) modified with di-sodium ethylenediamine tetra-acetic acid (EDTA) is used as a sensor for the simultaneous detection and quantification of Pb(II), Cu(II) and Co(II) in drinking water. The performance of this sensor is revealed by two electrochemical methods; Square Wave Voltammetry (SWV) and Cyclic Voltammetry (CV). The sensor is highly selective, allowing the electrochemical identity of Pb(II), Cu(II) and Co(II) to be revealed simultaneously. The sensor surface was studied by Energy Dispersive Spectrometry (EDX) coupled with Scanning Electron Microscope (SEM). The SWV determination coefficient (R2 = 0.93) is lower than that obtained by cyclic voltammetry (R2 = 0.9831), indicating that the predictive power of the latter is stronger. The recovery rate obtained per CV (concentration found * 100 / concentration added) is between 76% and 114%, indicating that the sensor developed is capable of analysing Pb(II) in drinking water with acceptable accuracy. The limit of detection and quantification of Pb(II) obtained by SWV is 8.87 × 10−9 mol / L and 2.95 × 10−8 mol / L respectively.

The nanoparticle ZnO-NP was manufactured by doping natural phosphate (NP) with zinc. The resulting sample was characterized by different techniques such as DRX, FT-IR, SEM. The ZnO-NP/CPE electrode has been applied for the simultaneous determination of Cd (II) and Hg (II). The electrochemical measurement of the elaborate sensor toward the hazardous metals ions was investigated by cyclic voltammetry (CV), and square wave voltammetry (SWV). The response of the electrochemical sensor indicates that the ZnO-NP/CPE electrode show a high performance electro analysis for Cd (II) and Hg (II). The suggested ZnO-NP electrode CPE has a linear straight line from 4.2 −21 µM and a lower detection limit (3σ) 4.2 for Cd (II) and 2.9 nM for Hg (II) under optimized experimental conditions. The elaborated sensor has been utilized with success for the simultaneous analysis of Cd (II) and Hg (II) in drinking water, and good results were achieved.

In this present study, we synthesized the NP-Al2O3 powder using impregnation method and it has been characterized by infrared spectroscopy (IR), SEM, X-ray diffraction, then was used as modifier in order to improve electroanalytical sensor trace heavy metal ions. The performance of the NP-Al2O3 to detect lead (II) and mercury (II) was studied using cyclic voltammetry (CV), square wave voltammetry in 0.3 mol/L NaCl. Under optimized experimental parameter, the developed NP-Al2O3 /CPE sensor has a lowest detection limit 0.756 nM for Pb (II) and 0.5 nM for Hg (II) respectively. The proposed working electrode was applied successfully for the co-analysis of lead (II) and mercury (II) in tap water, and then we obtained good results.

A simple and sensitive electroanalytical method was developed to determine the Endocrine Disrupting chemical 4-tert-octylphenolon clay modified carbon paste electrode (Clay/CPE). The electrochemical response of the proposed electrode was studied by meansof cyclic and square wave voltammetry. The structural morphology of the modified electrode was characterized by SEM/EDX andXRDtechniques.Ithasbeenfoundthattheoxidationof4-tert-octylphenolontheclay/CPEdisplayedawell-definedoxidationpeak.Factorsinfluencingthedetectionprocesseswereoptimized.4-tert-octylphenoloxidationoccurredthroughasurfaceprocessinvolvingits adsorption on the clay/CPE. Under these optimal conditions, a linear relation between concentrations of 4-tert-octylphenolandcurrent response was obtained over the range of 7.26 × 10

The inhibition efficiency of eugenol in controlling corrosion of titanium grade 2 in saliva medium containing bacteria at different pH has been evaluated by electrochemical polarization methods, and electrochemical impedance spectroscopy. The electrochemical data show that the corrosion resistance is greatly enhanced after surface modification. The best protection is obtained with eugenol at pH 7. The Scanning electron microscopy analysis showed that theses inhibitors act by establishment of a thin film at the metal surface. The film, act as a barrier to the transport of the metal ions from the metal to the solution at high concentration of inhibitor acts by establishment of a thin film at the metal surface.

Herein, we report a simple and inexpensive way for the fabrication of a microelectrode, DNA modified carbon paste electrode (DNA-CPE). DNA is deposited onto carbon paste electrode surface by self-assembled monolayers. The electrochemical behaviour of DNA-CPE’s was studied by cyclic voltammetry (SWV) tests. The recorded CV’s showed two redox peacks simultaneously at E oxidation=0.3 V and E reduction=0.2 V. The recorded SWV curves at DNA-CPE have shown great efficiency in the analysis of mercury (II) at different concentrations.

A new electrode based on garlic is prepared to inhibit the effect of oxidative stress, often linked to the presence of an excess of free radicals. The electrode paste was prepared as a mixture of finely powdered of garlic together with graphite powder. The influence of variables such as the garlic loading and free radicals concentration was tested by square wave voltammetry (SWV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The obtained results were found in good correlation with garlic reputation.

The electrochemical behavior of ammonium was investigated at Ethylene Diamine Tetra-Acetic -modified carbon paste electrode (EDTA-CPE) in NaCl solution. A method was developed for the detection of the trace of this product, based on their redox reaction. The redox peaks of ammonium were observed around -0.50 V and 0.50 V (vs. SCE) in cyclic voltammetry. Experimental conditions were optimized by varying the accumulation time, EDTA loading and measuring solution pH. Calibration plots were linear under the optimized parameters over the herbicides concentration range 0.8 and 16 mmol L-1, with a detection and quantification limits about 9.38.10-7 mol L-1 and 3.21.10-6 mol L-1, respectively.

This work aims to investigate the electro reduction of nitrate at copper elecrode in HClO 4 medium by the linear sweep voltammetry and convuctivity measurement methods. Two charge transfer steps were detected, the first one corresponding to adsorption and reduction of nitrate to nitrite and the second step consists of reducing nitrate to monoxide of nitrogen.

The objective of this study was to demonstrate the effect of eugenol on the titanium corrosion in artificial saliva enriched with eugenol at different concentration. The corrosion behaviour and titanium surface characterization were investigated by electrochemical measurements and SEM.

Paraquat is one of the most widely used herbicides in the world. It has had a tarnished reputation because of its acute oral toxicity and ill-health associated with operators - particularly in the plantation sectors of many developing countries. Paraquat binds rapidly and tightly to clay materials in soils, and when adsorbed it is biologically inactive. It also binds to humus and other organic material: this results in no, or very low soil residues or leaching into water sources. This article presents a studies of kinetic of adsorption onto hydroxyapatite phosphocalcique Ca10(PO4)6(OH)2 (HAP) from aqueous solution. Measurements are performed by electrochemical methods using the cyclic voltammetric, chronoamperometry and square wave voltammetry at carbon paste electrode (CPE).

The behaviour of the 316 stainless steel in polluted phosphoric acid, has been studied in absence and presence of [(4-Hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-phenyl-methyl]-urea (HPU1) and [(4-Hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-(4-methoxy-phenyl)-methyl]-urea (HPU2) at different concentrations, Potentiodynamic and electrochemical impedance measurements showed that these compound act as cathodic inhibitors, The SEM analysis showed that theses inhibitors acts by establishment of a thin film at the metal surface. The film, act as a barrier to the transport of the metal ions from the metal to the solution at high concentration of inhibitor.

The performance of organic compounds such as, benzimidazolethiole, modified carbon paste electrode was investigated as an electrochemical sensor in the determination of lead in 0.1m phosphate buffer solution at pH 6. The organic product, 2-benzimidazole thiol, was synthesized in the laboratory to be used as modifier of the carbon paste electrode (CPE), and its complex formation with Pb (II) was studied by square wave voltammetry and cyclic voltammetry. It was found that the organic film modified electrode shows a better performance than the carbon paste electrode (CPE). Under optimal conditions, the electrode showed a good linear response to lead (II). The proposed method was applied for possible chelating agent for heavy metals.

In this paper, a novel antibiotic modified carbon paste electrode (AMX-CPE) was fabricated for the directly determination of bacteria, such Staphylococcus aureus in physiological media. Electrochemical properties and morphological study of the modified electrode were greatly studied. We report a sensitive electrochemical voltammetric method for the immediate bacteria analyzing. A Staphylococcus bacterium adsorbed on an AMX-CPE surface and provides facile electrochemical quantitative methods for electroactive bacteria. Operational parameters have been optimized, and the stripping voltammetric performance has been studied using cyclic voltammetry (CV). The peaks current intensity is highly linear, with a good sensitivity of AMX-CPE.

The aim of this work is to introduce bacteria into the matrix of natural phosphate to catalyze the phenol oxidation. The results showed that the NP-bacteria-CPE exhibited excellent electro catalytic activity to phenol. The appearance of three peaks of oxidation shows that the degradation of the phenol was total.

Bioelectrochemical systems based on polymer-bacteria thin film modified electrode were explored. The prepared polymer-bacteria modified copper electrode was characterized with voltametric methods, as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The proposed electrode indicated a definite redox response, high conductivity and electrochemical stability. The experimental results revealed that the prepared electrode could be a feasible for degradation of hazardous phenol pollutants

The electrochemical behavior of bacteria, such Staphylococcus aureus, at clay modified carbon paste electrode is reported. The influence of variables such as the accumulation time, optical density (OD) was tested by square wave voltammetry (SWV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The interaction of bacteria and metal surface is discussed. A novel clay electrode (Arg-E) was fabricated for directly determination of bacteria in water or whole blood samples. The optical density of bacteria (OD) was determined and its evolution with the current density was plotted.

The carbon paste electrode (CPE) has been used to analyze the electrochemical behavior of paraquat (PQ) adsorbed onto synthesized hydroxyapatite phosphocalcique (HAP) in K2SO4 (0.1M). The cyclic voltammetry results obtained corrobate with square wave voltammetry. The influence of variables such as the concentration of paraquat adsorbed onto apatite (PQ/HAP), and the potential scan rate was tested.X-ray diffraction analysis (XRD), Fourier transformed infrared spectroscopy (FTIR) analysis and inductively coupled plasma-atomic emission spectrometry (ICP, AES) were used for characterization of the apatite.

The voltammetric behavior of paraquat was investigated at hydroxyapatite-modified carbon paste electrode HAP-CPE in K2SO4. A method was developed for the detection of the trace of this herbicide, based on their redox reaction. The reduction peaks of paraquat were observed around −0.70 V and −1.00 V (vs. SCE) in square-wave voltammetry. Experimental conditions were optimized by varying the accumulation time, apatite loading and measuring solution pH. Calibration plots were linear under the optimized parameters over the herbicide's concentration range 8–200×10−7 mol L−1, with a detection and quantification limits about 1.5×10−8 mol L−1 and 6.4 10−8 mol L−1, respectively.

The objective of this study was to demonstrate the effect of eugenol on the titanium corrosion in artificial saliva enriched with eugenol at different concentration. The corrosion behaviour and titanium surface characterization were investigated by electrochemical measurements and SEM.

We report a sensitive electrochemical voltammetric method for analyzing diquat (DQ) ions using a carbon paste electrochemical (CPE) modified by porous material, such as hydroxyapatite (HAP). Diquat strongly adsorbed on a HAP-CPE surface and provides facile electrochemical quantitative methods for electroactive DQ ions. Operational parameters have been optimized, and the stripping voltammetric performance has been studied using square wave voltammetry. The peaks current intensity are highly linear over the 7×10-7–3×10-4 mol L-1 diquat range examined (10-min accumulation time), with a good sensitivity. These findings can lead to a widespread use of electrochemical sensors to detect DQ contaminates.Scanning electron microscopy was used for morphology observation and in particular the X-ray diffraction analysis (XRD) and Fourier transformed infrared spectroscopy (FTIR) analysis for characterization of synthesis powder.

The analytical performance of developed DNA film screen printed biosensors designed for the detection of metals was evaluated. The modified surface exhibited an affinity to chelating metal ions in solution, forming complexes. Square wave voltammetry combined with a pre-concentrating process and standard additions were employed for trace analysis. Finally, cyclic voltammetry technique was used to characterize the developed DNA film surface behavior in presence of heavy metal.

We report a sensitive electrochemical voltammetric method for analyzing p-Chloroaniline using a carbon paste electrochemical (CPE) modified by porous material, such Clay (C). P-Chloroaniline strongly adsorbed on a C-CPE surface and provides facile electrochemical quantitative methods for electroactive p-Chloroaniline (p-CA). Operational parameters have been optimized, and the stripping voltammetric performance has been studied using square wave voltammetry. The peaks current intensity are highly linear, with a good sensitivity of C-CPE. These findings can lead to a widespread use of electrochemical sensors to detect chloroaniline contaminates.

A series of new benzamides were synthesized. The chemicals structures were confirmed by elemental analyses 1H NMR and 13C studies. The antioxidant activity of the synthesized compounds was evaluated by square wave voltammetry. A new approach, for antioxidant capacity determination was proposed. It is based on the using of the xanthine-xanthine oxidase system coupled with H2O2 electrochemical sensor.

The analytical performance of developed organic film screen –printed sensors designed for the detection of metals was evaluated. The modified surface exhibited an affinity to chelating metal ions in solution, forming complexes. Square wave voltammetry combined with a pre-concentrating process and standard additions were employed for trace analysis. Finally, cyclic voltammetry technique was used to characterize the developed organic film surface behavior in presence of different metals.

Three organic molecules were used as modifiers of carbon paste electrodes (CPEs) for the analysis of different metals (Pb2+, Cd2+ and Cu2+) by using Square Wave Voltammetry (SWV) technique. The effect of the modified electrodes (MO-CPEs) on the electrochemical behavior has been shown. The MO-CPEs gives the more sensitivity. The detection limits obtained in all analysis approaching 10-8 mol/L.

This work aims to investigate the electro oxidation of methanol, in alkaline solution at a copper electrode modified with electrodeposited natural phosphate and nickel (Ni-NP/Cu), by cyclic voltammetry, impedance measurements and square wave voltammetry. Morphological characterizations were performed by SEM and XRD techniques. It was found that Ni dispersed on natural phosphate (NP) shows a catalytic activity towards methanol oxidation better than massive Ni. Ni and NP were fixed on copper electrode by electro deposition using potentiostatic and galvanostatic techniques.