• Title, Summary, Keyword: Voltammetry

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Semi-Circular Potential Sweep Voltammetry: Electrochemically Quasi-Reversible System

  • Park, Kyungsoon;Hwang, Seongpil
    • Journal of Electrochemical Science and Technology
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    • v.11 no.4
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    • pp.379-383
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    • 2020
  • The novel voltammetry using a semi-circular potential wave for quasi-reversible charge transfer system on electrode is theoretically investigated. Compared with conventional voltammetry based on linear sweep such as linear sweep voltammetry (LSV), semi-circular potential sweep voltammetry (SCV) may decrease the charging current outside the center of potential range and increase the faradaic current at the midpoint due to variable scan rate. In this paper, we investigate the system based on macroelectrode where simple 1 dimensional (1 D) diffusion system is valid with various charge transfer rate constant (k0). In order to observe the amplification at midpoint, voltammetric response with different midpoint ranging from -200 mV to 200 mV are studied. SCVs shows both the shift of peak potential and the amplification of peak current for quasi-reversible electrode reaction while only higher peak current is observed for reversible reaction. Moreover, the higher current at midpoint enable the amplification of current at low overpotential region which may assist the determination of onset potential as a figure-of-merit in electrocatalyst.

The Determination of Germanium(IV) by Linear Sweep Voltammetry and UV-VIS Spectrophotometry (Linear Sweep Voltammetry와 UV-VIS Spectrophotometry를 이용한 게르마늄 분석)

  • Choi, Won-Hyung;Lee, Jin-Sik;Kim, Jae-Soo;Kim, Do-Hun
    • Analytical Science and Technology
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    • v.5 no.1
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    • pp.7-15
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    • 1992
  • Germainium(IV) was determined in perchloate supporting electrolyte solution containing phenylfluorone by hanging mercury drop electrode(HMDE) of Linear Sweep Voltammetry(LSV) and in hydrochloric acid solution by UV-VIS Spectrophotometry. The complex germanium(IV) with phenylfluorone was shown linear calibration curve in the range of $2.5{\sim}80{\mu}g/L$ by LSV and in the range of $10{\sim}300{\mu}g/L$ by UV-VIS Spectrophotometry.

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A Study on Voltammetry System Design for Realizing High Sensitivity Nano-Labeled Sensor of Detecting Heavy Metals (중금속 검출용 고감도 나노표지센서 구현을 위한 볼타메트리 시스템 설계 연구)

  • Kim, Ju-Myoung;Rhee, Chang-Kyu
    • Journal of Korean Powder Metallurgy Institute
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    • v.19 no.4
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    • pp.297-303
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    • 2012
  • In this study, voltammetry system for realizing high sensitivity nano-labeled sensor of detecting heavy metals was designed, and optimal system operating conditions were determined. High precision digital to analog converter (DAC) circuit was designed to control applied unit voltage at working electrode and analog to digital converter (ADC) circuit was designed to measure the current range of $0.1{\sim}1000{\mu}A$ at counter electrode. Main control unit (MCU) circuit for controlling voltammetry system with 150 MHz clock speed, main memory circuit for the mathematical operation processing of the measured current value and independent power circuit for analog/digital circuit parts to reduce various noise were designed. From result of voltammetry system operation, oxidation current peaks which are proportional to the concentrations of Zn, Cd and Pb ions were found at each oxidation potential with high precision.

Eletrochemical Detection of Gene using Microelectrode-array DNA Chip (미소전극어레이형 DNA칩을 이용한 유전자의 전기화학적 검출)

  • ;;Eiichi Tamiya
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.7
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    • pp.729-737
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    • 2004
  • In this paper, a DNA chip with a microelectrode array was fabricated using microfabrication technology. Several probe DNAs consisting of mercaptohexyl moiety at their 5 end were immobilized on the gold electrodes by DNA arrayer. Then target DNAs were hybridized and reacted with Hoechst 33258, which is a DNA minor groove binder and electrochemically active dye. Linear sweep voltammetry or cyclic voltammetry showed a difference between target DNA and control DNA in the anodic peak current values. It was derived from Hoechst 33258 concentrated at the electrode surface through association with formed hybrid. It suggested that this DNA chip could recognize the sequence specific genes.

Photophysical Parameters, Photodecomposition, Fluorescence Quenching and Convolutive Voltammetry of 7-Diethylaminocoumarin (DEAC) Laser Dye (7 Diethylaminocoumarin (DEAC) 레이져 염료의 광물리적 파라미터, 광분해, 형광 소광 및 Convolutive Voltammetry)

  • El-Daly, S.A.;El-Hallag, I.S.
    • Journal of the Korean Chemical Society
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    • v.54 no.1
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    • pp.13-22
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    • 2010
  • The photophysical properties of 7-diethylaminocoumarin (DEAC) laser dye have been measured in different solvents. The emission spectrum of DEAC has also been measured in cationic (CTAC) and anionic (SDS) micelles. The laser parameters have been calculated in different solvents namely acetone, dioxane, ethanol and dimethylforamide(DMF). The photoreactivity of DEAC has been studied in $CCl_4$ solvent using 366 nm light. The values of photochemical yield (${\Phi}_c$) and rate constant (k) are determined. The interaction of organic acceptors such as picric acid (PA), tetracyanoethylene (TCNE) and 7,7,8,8-tetracynoquinonedimethane (TCNQ) with DEAC are also studied using fluorescence measurements in acetonitrile ($CH_3CN$). The electrochemical investigation of (DEAC) has been carried out using cyclic voltammetry and convolutive voltammetry combined with digital simulation technique at a platinum electrode in 0.1 mol $L^{-1}$ tetrabutyl ammonium perchlorate (TBAP) in $CH_3CN$ solvent. The electrochemical parameters of the investigated compound were determined using cyclic and convolutive voltammetry. The extracted electrochemical parameters were verified and confirmed via digital simulation method.

Convolutive Cyclic Voltammetry Investigation of Dicarboximide Laser Dye at a Platinum Electrode in 1,2-Dichloroethane (1,2-Dichloroethane 내 백금 전극에서의 dicarboximide 레이저 염료에 대한 convolutive 순환 전압-전류법 연구)

  • Al-Bishri, Hassan M.;El-Mossalamy, E.H.;El-Hallag, Ibrahim;El-Daly, Samy
    • Journal of the Korean Chemical Society
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    • v.55 no.2
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    • pp.169-176
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    • 2011
  • The electrochemical investigation of N,N-bis (2,5-di-tert-butylphenyl)-3,4,9,10 perylenebis (dicarboximide) laser dye have been carried out using cyclic voltammetry and convolution - deconvolution voltammetry combined with digital simulation technique at a platinum electrode in 0.1 mol/L tetrabutyl ammonium perchlorate (TBAP) in solvent 1,2 dichloroethane ($CH_2Cl-CH_2Cl$). The investigated dye was reduced via consumption of two sequential electrons to form radical anion and dianion (EE mechanism). In switching the potential to positive scan, the compound was oxidized by loss of two electrons, which were followed by a fast aggregation process ($EC_1EC_2$ mechanism). The electrode reaction pathway and the chemical and electrochemical parameters of the investigated compound were determined using cyclic voltammetry and convolutive voltammetry. The extracted electrochemical parameters were verified and confirmed via digital simulation method.

Basic Studies on the Recovery of Zinc Metal from Wastewater by Cyclic Voltammetry (循環走査법에 의한 廢水로부터 亞鉛 回收에 관한 基礎 硏究)

  • 김진화;김동수
    • Resources Recycling
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    • v.10 no.3
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    • pp.29-36
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    • 2001
  • Cyclic voltammetry has been applied in the basic studies for the treatment and recovery of heavy metal component contained in wastewater by electrochemical reduction. The electrochemical behaviors of zinc ion for zinc metal electrode and carbon elec-trode were characterized by voltammograms and it was showed that zinc ions were reduced to metallic form below -0.76 V vs SHE. The change in the features of crystalline form of metallic zinc upon oxidation and reduction reaction was observed by X-ray diffraction method and the Am analysis verified that zinc ions were reduced to metal on copper plate. The results of this study were regarded to be important and meaningful in the treatment of heavy metal containing wastewater and, as a result, in the obtainment of metallic product by electrochemical method.

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Effect of copper surface to $HNO_3$ and $KNO_3$ electrolyte ($KNO_3$$HNO_3$ 전해액이 Cu에 미치는 영향)

  • Seo, Yong-Jin;Han, Sang-Jun;Park, Sung-Woo;Lee, Young-Kyun;Lee, Sung-Il
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.486-486
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    • 2009
  • In this paper, the current-voltage (I-V) curves, such as linear sweep voltammetry (LSV) and cyclic voltammetry (CV), were employed to evaluate the effect of electrolyte concentration on the electrochemical reaction trend. From the I-V curve, the electrochemical states of active, passive, transient and trans-passive could be characterized. And then, we investigated that how this chemical affect the process of voltage-induced material removal in electrochemical mechanical polishing (ECMP) of Copper. The scanning electron microscopy (SEM) and energy dispersive spectroscopy EDS) analyses were used to observe the surface profile. Finally, we monitored the oxidation and reduction process of the Cu surface by the repetition of anodic and cathodic potential from cyclic voltammetry (CV) method in acid- and alkali-based electrolyte. From these analyses, it was important to understand the electrochemical mechanisms of the ECMP technology.

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Determination of Ag(Ⅰ) Ion at a Modified Carbon Paste Electrode Containing N,N'-Diphenyl Oxamide

  • Won, Mi-Sook;Yeom, Jeong-Sik;Yoon, Jang-Hee;Jeong, Euh-Duck;Shim, Yoon-Bo
    • Bulletin of the Korean Chemical Society
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    • v.24 no.7
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    • pp.948-952
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    • 2003
  • New approach for the determination of Ag(I) ion was performed by using a carbon paste electrode (CPE) containing N,N'-Diphenyl oxamide (DPO) with anodic stripping voltammetry. The CMEs have been prepared by making carbon paste mixtures containing an appropriate amount of DPO salt coated onto graphite particles to analyze trace metal ions via complexation followed by stripping voltammetry. Various experimental parameters affecting the response, such as pH, deposition time, temperature, and electrode composition, were carefully optimized. Using differential pulse anodic stripping voltammetry, the logarithmic linear response range for the Ag(I) ion was 1.0 × $10^{-7}$ - 5.0 × $10^{-9}$ M at the deposition time of 10 min, with the detection limit was 7.0 × $10^{-10}$ M. The detection limit adopted from anodic stripping differential pulse voltammetry was 7.0 × $10^{-10}$ M for silver and the relative standard deviation was ± 3.2% at a 5.0 × $10^{-8}$ M of Ag(I) ion (n = 7). The proposed electrode shows a very good selectivity for Ag(I) in a standard solution containing several metals at optimized conditions.