• Proceedings of the KIEE Conference
• /
• 2004.07c
• /
• pp.2131-2133
• /
• 2004

모세관 전기영동 및 전기화학적 검출 시스템을 마이크로 시스템에 적용하여 ITO 유리기판과 polydimethylsiloxane (PDMS)로 제작하였다. 제작된 모세관 전기영동 및 전기화학적 검출 시스템은 일회용으로 사용가능하며 전기화학적 검출에 아주 적합한 특성을 보인다. 모세관 전기영동 및 전기화학적 검출 시스템은 주입과 분리 채널 (80 ${\mu}m$ 폭 ${\sim}$ 40 ${\mu}m$ 깊이)을 가진 PDMS 층과 유리기판 위에 검출 전극으로 사용되는 ITO가 형성된 층으로 구성된다. PDMS 층과 ITO 유리 기판은 UV-$O_3$ cleaner를 사용하여 접합하였다. 완충용액은 10 mM 2-(N-morpholino)ethanesulfonic acid (MES)를 사용하였고 분석물질은 1 mM 농도의 dopamine과 1 mM 농도의 catechol을 사용하였다. 60 V/cm 전계로 주입 및 분리를 하였으며 작업전극과 기준전극 간의 전위는 +600 mV로 유지하며 분석물질의 농도에 비례하는 전류량법으로 측정하였다. 전기화학적 검출 회로는 천기영동 전계의 간섭으로부터 분리하였다. 10 mM MES 완충용액에서 바탕 전류의 크기가 ${\sim}$10 pA 일 때 측정전류 값은 10 nA이다. 측정된 피크 값은 기존의 Au 전극과 비교하여 선택성, 감도, 분해능이 유사한 특성을 보여준다.

• Resources Recycling
• /
• v.10 no.3
• /
• pp.29-36
• /
• 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.

• Journal of Environmental Science International
• /
• v.5 no.5
• /
• pp.677-682
• /
• 1996

The electrochemical carbon dioxide reduction to produce acetaldehyde, methanol and ethanol is investigated by using perovskite type electrode ($La_{0.9}$$Sr_{0.1}$$CuO_3$). The experiments were Performed under 100 mA/cm2 and -2 to -2.5 V vs. Ag/AgCl. The highest faradaic efficiencies for methanol, ethanol, acetaldehyde were 11.6, 15.3, and 6.2%, respectively. The experimental data demonstrated that the capability of the perovskite type oxide for the electrode of electrochemical carbon dioxide reduction to produce alcohols was superior to other metal electrode. Key words : Perovskite, Electrode, Alcohol Formation, Electrochemical Reduction, Carbon Dioxide Fixation.

• Journal of Advanced Marine Engineering and Technology
• /
• v.19 no.2
• /
• pp.56-66
• /
• 1995

Recently, with theraped advancement in th oceanology such an ocean-going vessel and oceanic structures, there is a need to study the cavitation erosion-corrosion control of pump impeller, the partial element of ocean machinery, for more effective operation. Especially, the cathodic protection (impressed current method & Al-sacrificial anode method) was applied to sea water, and Cu-alloy material mixed Zn & Al was used as a control method of cavitation erosion-corrosion. In this study, used the piezoelectric vibrator with 20KHz, 24.mu.m to cavity generation apparatus, and investigated the weight loss, weight loss rate, electrode potential & current density etc. under this condition. According to test result, thos describes how to indentify an influence of the cathodic protection and Al & Zn addition in material development for the control of cavitation erosion-corrosion, and those will serve as fundamental data on the cavitation erosion-corrosion control of oceanic centrifugal pump.

• Journal of the Korean Chemical Society
• /
• v.27 no.2
• /
• pp.111-116
• /
• 1983

Three component $Ag_2S-PbS-PbWO_4$ electrodes have been prepared and evaluated for sensitivity to tungstate. The 51.71 : 16.64 : 31.65(w/w%) composition is superior in terms of potentiometric response, stability, rapidity of response and reproducibility. Testing was done over the concentration range $10^{-1}~10^{-4}M WO_4^{2-}$ in $0.1F-NH_4Ac-NH_4OH$ buffer at pH 8.00 with constant ionic strength. The quality of response is similar to that of corresponding phosphate-sensing electrode. Many common ions interfere.

• Journal of the Korean Electrochemical Society
• /
• v.13 no.2
• /
• pp.132-137
• /
• 2010

This study is concerned the electrocatalytic generation of oxygen gas at electrochemically deposited manganese oxide electrode in KOH solution. Manganese oxide nanoparticles electrodeposited onto relatively substrate, e.g glassy carbon, Au, Ti electrode. MnOx is electrodeposited in nanorod structure which cover the overall surface of the substrate. The $\gamma$-MnOOH that is kind of manganese oxide species plays a significant role as a catalytic mediator, which promote 4-electron reduction process. Modified electrodes with electrodeposited manganese oxide structures resulted in significant decrease in the anodic polarization compared with the unmodified electrodes in alkaline media.

• Journal of the Korean Chemical Society
• /
• v.57 no.5
• /
• pp.533-539
• /
• 2013

The electrochemical corrosion and passivation of Ni rotating disk electrod in borate buffer solution was studied with potentiodynamic and electrochemical impedance spectroscopy. The mechanisms of both the active dissolution and passivation of nickel and the hydrogen evolution in reduction reaction were hypothetically established while utilizing the Tafel slope, impedance data, the rotation speed of Ni-RDE and the pH dependence of corrosion potential and current. Based on the EIS data, an equivalent circuit was suggested. In addition, carefully measured were the electrochemical parameters for specific anodic dissolution regions. It can be concluded from the data collected that the $Ni(OH)_2$ oxide film, which is primarily formed by passivation, is converted to NiO by dehydration under the influence of an electrical field.

• Analytical Science and Technology
• /
• v.20 no.3
• /
• pp.213-218
• /
• 2007

Copper(II) ion was measured with the use of a perfluorinated sulfonated polymer-ethylenediamine (nafion-en) modified glassy carbon electrode. The electrode mechanism was based on the chemical reactivity of an immobilized layer (nafion-en) to yield complex $[Cu(en)_2]^{+2}$. The reduction potential peak by differential pulse voltammetry(DPV) was observed at -0.4402V(${\pm}0.0050V$) (vs. Ag/AgCl). The linear calibration curve was obtained from $1.0{\times}10^{-6}$ to $1.0{\times}10^{-4}M$ copper(II) ion concentration, and the detection limit(3s) was $1.96{\times}10^{-6}M$.

• Analytical Science and Technology
• /
• v.14 no.2
• /
• pp.123-130
• /
• 2001

Determination of cadmium(II) ion with a perfluorinated sulfonated polymer-ethylenediamine(nafion-en) modified glassy carbon electrode was studied. It was based on the chemical reactivity of an immobilized layer(nafion-en) to yield complex $[Cd(en)_2]^{2+}$. The reduction peak potential by differential pulse voltammetry(DPV) was observed at $-0.780({\pm}0.005)V$ vs. As/AgCl. The linear calibration curve was obtained in cadmium(II) ion concentration range $5.0{\times}10^{-7}-2.0{\times}10^{-5}M$, and the detection limit(3s) was $2.20{\times}10^{-7}M$. The detection limit of nafion-en modified glassy carbon electrode has been shown about 14 higher sensitivity than a bare glassy carbon electrode.

• Journal of Environmental Science International
• /
• v.5 no.2
• /
• pp.211-220
• /
• 1996

New thin-and diselena-crown ethers containing two suffer and selenium donor atoms have been prepared. And then, mercury ($Hg^{2+}$) ion-selective electrodes with PVC-plasticizer (STPB) based on some macrocycles as neutral carriers were also made. The electrochemical selectivities for various ions, and the effects for macrocycles, matrix of membranes, ratio of plasticizer to macrowcles, concentration and pH of test solution were investigated on the $Hg^{2+}$ ion-selective electrodes. The 1, 10-diselena-18-crown-6-PVC-STPB (sodium tetraphenylborate) exhibited good linear responses of ${28.2}\pm{0.6}$ decade-1 for $Hg^{2+}$ ion in the conientration ranges of $10^{-2}~10^{-6}$ M $Hg^{2+}$ ion. This electrode exhibited comparatively good selectivities for $Hg^{2+}$ ion in comparison with alkali and alkaline earth metal ions, some heavy metal ions and rare earth metal ion in the range of pH 2.5~6.0. In addition, this electrode was applied as a sensor in the titration of $Hg^{2+}$ ion with $1^-$ ion in water.