scholarly journals pH Controlled Impedimetric Sensing of Copper(II) Ion Using Oxytocin as Recognition Element

Surfaces ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 90-95 ◽  
Author(s):  
Kiran Tadi ◽  
Israel Alshanski ◽  
Mattan Hurevich ◽  
Shlomo Yitzchaik
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Surface Chemistry ◽  
Glassy Carbon ◽  
Electrochemical Impedance ◽  
Carbon Electrode ◽  
Recognition Element ◽  
High Affinity ◽  
Specific Metal ◽  
Selective Sensor

We report the modulation of the specific metal gation properties of a peptide and demonstrate a highly selective sensor for copper(II) ion. The neuropeptide oxytocin (OT) is reported for its high affinity towards Zn2+ and Cu2+ at physiological pH. The binding of the metal ions to OT is tuned by altering the pH of the medium. OT was self-assembled on glassy carbon electrode using surface chemistry, and electrochemical impedance spectroscopy (EIS) was used to probe the binding of Cu2+. Our results clearly indicate that at pH 10.0, the binding of Cu2+ to OT is increased compared to that at pH 7.0, while the binding to Zn2+ becomes almost negligible. This proves that the selectivity of OT towards each of the ions can be regulated simply by controlling the pH of the medium and hence allows the preparation of a sensing device with selectivity to Cu2+.

The influence of gold nanoparticles on the electroactivity of nickel tetrasulfonated phthalocyanine

2014 ◽  
Vol 18 (08n09) ◽  
pp. 642-651 ◽  
Author(s):  
Audacity Maringa ◽  
Tebello Nyokong
Keyword(s):  
Gold Nanoparticles ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Glassy Carbon ◽  
Electrochemical Impedance ◽  
Modified Electrodes ◽  
Enhancement Effect ◽  
Carbon Electrode ◽  
Cathodic Peak ◽  
Peak Separation

We report on the electrodeposition of gold nanoparticles ( AuNPs ) on a glassy carbon electrode (GCE) followed by deposition of nickel tetrasulfonated phthalocyanine ( NiTSPc ) film by electropolymerization (poly- NiTSPc -GCE) to form Poly- NiTSPc / AuNPs -GCE. The presence of the gold nanoparticles caused a lowering of the anodic and cathodic peak separation (ΔE p ) of ferricyanide from 126 mV on poly- NiTSPc to 110 mV on poly- NiTSPc / AuNPs . The electrooxidation of nitrite improved on modified electrodes compared to GCE, with the latter giving E p = 0.78 V and the modified electrodes gave E p = 0.62 V or 0.61 V. Poly- NiTSPc / AuNPs -GCE had higher currents compared to poly- NiTSPc -GCE. This indicates the enhancement effect caused by the AuNPs . Electrochemical impedance spectroscopy and chronoamperometric studies also showed that poly- NiTSPc / AuNPs -GCE was a better electrocatalyst than poly- NiTSPc -GCE or AuNPs -GCE.

scholarly journals Investigation of Electrochemical Behaviour of Quercetin on the Modified Electrode Surfaces with Procaine and Aminophenyl in Non-Aquous Medium

2008 ◽  
Vol 5 (3) ◽  
pp. 539-550 ◽  
Author(s):  
Ibrahim Ender Mulazimoglu ◽  
Erdal Ozkan
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Glassy Carbon ◽  
Electrode Surface ◽  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Carbon Electrode ◽  
Amine Group ◽  
Tetrabutylammonium Tetrafluoroborate

In this study, cyclic voltammetry and electrochemical ımpedance spectroscopy have been used to investigate the electrochemical behaviour of quercetin (3,3′,4′,5,7-pentahydroxyflavone) on the procaine and aminophenyl modified electrode. The modification of procaine and aminophenyl binded electrode surface with quercetin was performed in +0,3/+2,8 V (for procaine) and +0,4/+1,5 V (for aminophenyl) potential range using 100 mV s-1scanning rate having 10 cycle. A solution of 0.1 M tetrabutylammonium tetrafluoroborate in acetonitrile was used as a non-aquous solvent. For the modification process a solution of 1 mM quercetin in 0.1 M tetrabutylammonium tetrafluoroborate was used. In order to obtain these two surface, a solution of 1 mM procaine and 1 mM nitrophenyl diazonium salt in 0.1 M tetrabutylammonium tetrafluoroborate was used. By using these solutions bare glassy carbon electrode surface was modified. Nitrophenyl was reduced to amine group in 0.1 M HCl medium on the nitrophenyl modified glassy carbon elelctrode surface. Procaine modified glassy carbon electrode surface was quite electroactive. Although nitrophenyl modified glassy carbon elelctrode surface was electroinactive, it was activated by reducing nitro group into amine group. For the characterization of the modified surface 1 mM ferrocene in 0.1 M tetrabutylammonium tetrafluoroborate for cyclic voltammetry and 1 mM ferricyanide/ferrocyanide (1:1) mixture in 0,1 M KCl for electrochemical impedance spectroscopy were used.

scholarly journals Evaluation of Reaction Property of Anodized Carbon Electrode by Electrochemical Impedance Spectroscopy

2014 ◽  
Vol 65 (9) ◽  
pp. 447-452 ◽  
Author(s):  
Yoshinao HOSHI ◽  
Kazuma KAWAKAMI ◽  
Isao SHITANDA ◽  
Masayuki ITAGAKI ◽  
Takuro MURAKAMI
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Carbon Electrode

Electrochemical Impedance Investigation of the Binding Properties of Phloretin to Egg Lecithin Liposomes

2013 ◽  
Vol 303-306 ◽  
pp. 863-866
Author(s):  
Ping Shen ◽  
Ming Xun Yan ◽  
Xu Qin Zhan ◽  
Chang Ying Yang
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Binding Constants ◽  
Association Constants ◽  
Gold Electrodes ◽  
Binding Properties ◽  
High Affinity ◽  
Egg Lecithin

Immobilization of egg lecithin liposomes on Octadecanethiol (ODT) modified gold electrodes has been studied. The changes of the resistance of the layer with deposited liposomes, occurred under stimulation by different concentration of phloretin were measured with electrochemical impedance spectroscopy (EIS) and were used for the calculation of association constants. The binding constants Kb was obtained to be (7.571±0.821)×105 L•mol-1, indicated that high affinity existed between phloretin and liposomes.

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