• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.27-31
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• 2003

A Polythiophene-quinoline/glassy carbon (PTQ/GC) modified electrode was developed for the determination of trace mercury in industrial waste water, natural water, soil, and other media. The electrode was prepared by the cyclic voltammetric polymerization of thiophene and quinoline on glassy carbon (GC) electrode by the potential application from -0.6 V to +2.0 V (50 mV/sec) in a solution of 0.1 M thiophene, quinoline and tetrabutyl ammonium perchlorate (TBAP) in acetonitrile. Optimum thickness of the polymer membrane on the GC electrode was obtained with 20 repeated potential cyclings. The redox behavior of Cu(Ⅱ) and Hg(Ⅱ) were almost identical on this electrode. The addition of 4-(2-pyridylazo)resorcinol (PAR) to the solution containing Cu(Ⅱ) and Hg(Ⅱ) allowed the separation of the components due to the formation of the Cu(Ⅱ)-PAR complex reduced at -0.8V, which was different from the Hg(Ⅱ) reduced at -0.5 V on a saturated calomel electrode (SCE). The calibration graph of Hg(Ⅱ) shows good linear relationship with the correlation factor of 0.9995 and the concentration gradient of 0.33 ㎂/㎠/ppb down to 0.4 ppb Hg. The method developed was successfully applied to the determination of mercury in samples such as river, waste water, and sea water.

• 한국환경보건학회지
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• 제26권4호
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• pp.110-114
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• 2000

Determination of mercury(II) using Nafion-EDTA-modified glassy carbon electrodes is proposed. it is based on the chemical reactivity of an immobilized modifier, Nafion-EDTA. Differential pulse voltammetry is employed, and the oxidation of complexes, at +0.43V vs. Ag/AgCl, is observed. For a 5-min preconcentration period, a linear calibration curve is obtained for mercury(II) concentrations ranging from 1.0$\times$ 10$^{-8}$ to 1.0$\times$10$^{-6}$ M. Further, when an approximate amount of copper(II) is added to the test solution, We demonstrate that at a preconcentration time of 5 min the Nafion-EDTA-modified glassy carbon electrode has a dynamic range of 2 orders of magnitude(from 10$^{-10}$ to 10$^{-8}$ M) and the detection limit is as low as 0.5$\times$ 10$^{-10}$ M(0.01 ppb). This method is applied to the determination of mercury(II) in sea water(4.0$\times$10$^{-10}$ M, 0.08ppb). The result agrees satisfactorily with the value(below 0.1 ppb) measured by using ICP/MS.

• 분석과학
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• 제20권3호
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• pp.213-218
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• 2007

Perfluorinated sulfonated polymer-ethylenediamine(nafion-en)이 수식된 유리탄소전극을 이용하여 Cu(II) 이온을 정량하였다. 이 수식전극의 en은 Cu(II) 이온과 $[Cu(en)_2]^{+2}$의 착물을 형성한다. Nafion-en이 수식된 유리탄소전극에서 시차펄스전압전류법에 의한 Cu(II) 이온의 환원봉우리전위는 -0.4402V(${\pm}0.0050V$) (vs. Ag/AgCl)에서 측정되었고, 측정범위는 $1.0{\times}10^{-6}{\sim}1.0{\times}10^{-4}M$, 검출한계(3s)는 $1.96{\times}10^{-6}M$이었다.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.810-816
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• 2009

The interactions between four Keggin-type POMs (${SiW_{12}O_{40}}^{4-},\;{PW_{12}O_{40}}^{3-},\;{SiMo_{12}O_{40}}^{4-},\;and\;{PMo_{12}O_{40}}^{3-}$) and glassy carbon (GC) and highly oriented pyrolytic graphite (HOPG) surfaces are investigated in a systematic way. Electrochemical results show that molibdate series POMs adsorb relatively stronger than tungstate POMs on GC and HOPG surfaces. Adsorption of POMs on HOPG electrode surfaces is relatively stronger than on GC surfaces. ${SiMo_{12}O_{40}}^{4-}$ species exhibits unique adsorption behaviors on HOPG surfaces. Surface-confined ${SiMo_{12}O_{40}}^{4-}$ species on HOPG surfaces exhibit unique adsorption behaviors and inhibit the electron transfer from the solution phase species. The catalytic activity of the surface-confined POMs for hydrogen peroxide electroreduction is also examined, where ${PW_{12}O_{40}}^{3-}$ species adsorbed on GC surfaces exhibits the highest catalytic efficiency among the investigated POM modified electrode systems.

• Bulletin of the Korean Chemical Society
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• 제19권5호
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• pp.584-587
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• 1998

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1215-1220
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• 2011

An electrochemically-modified electrode [P(EDOP-SWNTs)/GCE] was prepared by electropolymerization of 3,4-ethylenedioxy pyrrole (EDOP) single-walled carbon nanotubes (SWNTs) on the surface of a glassy carbon electrode (GCE) and characterized by SEM, CV, and DPV. This modified electrode was employed as an electrochemical biosensor for the selective determination of serotonin concentrations at pH 7.4 and exhibited a typical enhanced effect on the current response of serotonin with a lower oxidation overpotential. The linear response was in the range of $1.0{\times}10^{-7}$ to $1.0{\times}10^{-5}$ M, with a correlation coefficient of 0.998 on the anodic current. The lower detection limit was calculated as 5.0 nM. Due to the relatively low currents and difference of potentials in the electrochemical responses of uric acid (UA), ascorbic acid (AA), and dopamine (DA), the modified electrode was a useful and effective sensing device for the selective and sensitive serotonin determination in the presence of UA, AA, and DA.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3077-3083
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• 2010

The electrochemical detection of As(III) was investigated on a platinum-iron(III) nanoparticles modified multiwalled carbon nanotube on glassy carbon electrode(nanoPt-Fe(III)/MWCNT/GCE) in 0.1 M $H_2SO_4$. The nanoPt-Fe(III)/MWCNT/GCE was prepared via continuous potential cycling in the range from -0.8 to 0.7 V (vs. Ag/AgCl), in 0.1 M KCl solution containing 0.9 mM $K_2PtCl_6$ and 0.6 mM $FeCl_3$. The Pt nanoparticles and iron oxide were co-electrodeposited into the MWCNT-Nafion composite film on GCE. The resulting electrode was examined by cyclic voltammetry (CV), scanning electron microscopy (SEM), and anodic stripping voltammetry (ASV). For the detection of As(III), the nanoPt-Fe(III)/MWCNT/GCE showed low detection limit of 10 nM (0.75 ppb) and high sensitivity of $4.76\;{\mu}A{\mu}M^{-1}$, while the World Health Organization's guideline value of arsenic for drinking water is 10 ppb. It is worth to note that the electrode presents no interference from copper ion, which is the most serious interfering species in arsenic detection.

• 한국막학회:학술대회논문집
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• 한국막학회 1993년도 추계 총회 및 학술발표회
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• pp.13-20
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• 1993

The sorption equilibria and permeation rates for carbon dioxide in such glassy polymer membranes with high glass-transition temperature as polyimide, polyetherimide, polysulfone and polyethersulfone membranes, were measured. The sorption isotherms for these systems can be described well by the dual-mode sorption model, whereas the pressure dependences of the mean permeability coefficients are simulated better by a modified dual-mode mobility model than the conventional dual-mode mobility model in which the Henry's law and Langmuir populations execute four kinds of diffusive movement.

• 대한화학회지
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• 제33권2호
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• pp.225-231
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• 1989

$trans-[Co(en)_2X_2](ClO_4)_n$가 Co(II) 상태의 착물로 (X : 시아나이드, 나이트라이트, 암모니아, 그리고 이소티오시아네이트)되는 전극 환원반응 속도상수를 탄소전극에서 순환전압전류법 및 회전원판전극을 이용하여 측정하고 수은전극에서 순환전압전류법 및 펄스폴라로그래피법으로 측정하여 착물의 분광학적 흡수파수와 관계를 조사하였다. 탄소전극에서는 흡수파수가 증가할 때 전극반응의 활성화자유에너지가 증가하며 좋은 직선성을 보이지만 $NO_2^-$가 배위된 착물의 경우에는 수은전극에서 흡수파수와 활성화에너지의 관계가 비선형적이었으며 활성화엔트로피 역시 크게 나타났고 전극반응 전이계수도 크게 얻어졌다. 수은전극에서는$NO_2^-$가 배위된 착물은 다른 착물과 다르게 innersphere 메카니즘으로 환원되며 $NO_2^-$가 수은전극 표면으로 배향되어 전자전이가 일어나는 것으로 제안하였다.

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1897-1901
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• 2010

Multi-wall carbon nanotube (MWNT)-modified glassy carbon electrodes (GCE) were prepared for simultaneous determination of rutin and quercetin. Microbial carbohydrates, $\alpha$-cyclosophorohexadecaose ($\alpha$-C16) and succinoglycan monomer M3 (M3) were doped into MWNTs to prepare a $\alpha$-C16-doped MWNT-modified GCE (($\alpha$-C16 + MWNTs)/GCE) and a M3-doped MWNT-modified GCE ((M3 + MWNTs)/GCE), respectively. The sensitivities of the ($\alpha$-C16 + MWNTs)/GCE to rutin and quercetin were 34.7 ${\mu}A\cdot{\mu}M^{-1}{\cdot}cm^{-2}$ and 18.3 ${\mu}A\cdot{\mu}M^{-1}{\cdot}cm^{-2}$, respectively, in a linear range of $2\sim8{\mu}M$ at pH 7.2. The sensitivities of the (M3 + MWNTs)/GCE was 2.44 ${\mu}A\cdot{\mu}M^{-1}{\cdot}cm^{-2}$ for rutin and 7.19 ${\mu}A\cdot{\mu}M^{-1}{\cdot}cm^{-2}$ for quercetin without interference.