• 한국응용과학기술학회지
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• 제31권2호
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• pp.210-217
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• 2014

For ex-vivo diabetic control, the voltammetric diagnosis of glucose (GU) was conducted with a modified carbon nanotube paste electrode, using handheld analytical circuits. The optimum analytical conditions were attained within the 0.5-4.0 ug/L working range and at the 0.06 ug/L detection limit, which system was interfaced to the feedback circuits and was applied to human urine for diabetic-patient diagnosis. It can be used for ex-vivo flow control analysis, vascular flow detection, and other medicinal assays.

• 한국응용과학기술학회지
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• 제30권1호
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• pp.139-145
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• 2013

The electrochemical analysis of silver ion was performed using cyclic voltammetry (CV) and square-wave (SW) stripping voltammetry, and electrode cell systems were fabricated with graphite pencil electrode (GE) of working, reference and counter electrodes. Also electrolyte was the use of sea water as electrolyte solutions instead of ionic controlled solutions. The optimum analytical conditions for the cyclic and stripping parameters were determined using GE. The results approached the microgram working ranges of SW(ug/L) and CV(ug/L) Ag, and the optimum conditions were applied to frog's tissue and the food samples.

• 한국응용과학기술학회지
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• 제31권4호
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• pp.663-668
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• 2014

An in-vivo diagnosis of trace Mg(II) ion was performed using a low-cost and environment-friendly voltammetric method, using a graphite counter and reference electrodes and a fluorine-immobilized graphite working electrode, and clean deep seawater was used as an electrolyte solution. Under optimum conditions, the analytical working ranges attained microgram ranges, and a detection limit of $80.6ugL^{-1}$ was obtained using stripping voltammety with 60 sec accumulation time. Ex-vivo application was performed on fish liver and mice droppings. The developed techniques can be applicable to tumor cell analysis.

• 한국응용과학기술학회지
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• 제33권4호
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• pp.726-733
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• 2016

A voltammetric analysis of doxycycline was developed using DNA immobilized onto a carbon nanotube paste electrode (PE). An anodic peak current was indicated at 0.2 V (versus Ag/AgCl) in a 0.1M $NH_4H_2PO_4$ electrolyte solution. The linear working range of the cyclic and square wave stripping voltammetry was obtained to $1-27ngL^{-1}$ with an accumulation time of 800 s. Final analytical parameters were optimized to be as follows: amplitude, 0.35 V; frequency, 500 Hz; and pH, 5.43. Here detection limit was found to be $0.45ngL^{-1}$, this result can be applied in foods systems and in the biological diagnostics

• Bulletin of the Korean Chemical Society
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• 제10권5호
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• pp.414-418
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• 1989

The electrochemical behavior of cadmium(Ⅱ) in tartrate solution has been studied over the pH range of 6 to 13.6 in order to explain the phenomena of the changes in limiting current depending on the pH. The polarographic limiting current showed a constant value up to pH of 7.8, after which it decreased sharply to show a minimum at pH between 11 and 12. The limiting current, then, increased again with increasing pH. The number of peaks in cyclic voltammogram was 1 to 3 depending on the pH of the solution. Two other voltammetric peaks could be observed when the main reduction peak diminished. The decrease of limiting current at 7.5$Cd(C_4H_3O_6)^-$. The increase of limiting current at strong alkaline solution, however, was due to the complex $Cd(Tart)_2(OH)_2^{4-}$.

• Bulletin of the Korean Chemical Society
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• 제22권5호
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• pp.481-487
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• 2001

Surface films formed prior to bulk reduction of lithium have been studied at gold, platinum, and copper electrodes in rigorously dried propylene carbonate solutions using electrochemical quartz crystal microbalance (EQCM) and secondary ion mass spectrometry experiments. The results indicate that the passive film formation takes place at a potential as positive as about 2.0 V vs. Li/Li+ , and the passive film thus formed in this potential region is thicker than a monolayer. Quantitative analysis of the EQCM results indicates that electrogenerated lithium reacts with solvent molecules to produce a passive film consisting of lithium carbonate and other compounds of larger molecular weights. The presence of lithium carbonate is verified by SIMS, whereas the lithium compounds of low molecular weights, including lithium hydroxide and oxide, are not detected. Further lithium reduction takes place underneath the passive film at potentials lower than 1.2 V with a voltammetric current peak at about 0.6 V.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1341-1345
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• 2011

A novel ruthenium(II) complex, [$RuCl_2(DMSO)_2$(PhenTPy)] has been synthesized by the condensation of $RuCl_2(DMSO)_4$ with (1-(1,10-phenanthrolinyl)-2,5-di(2-thienyl)-1H-pyrrole)[PhenTPy] in $CHCl_3$ solution. The [$RuCl_2(DMSO)_2$(PhenTPy)] complex modified electrode was fabricated through the electropolymerization of the monomer in a 0.1 M tetrabutylammonium perchlorate (TBAP)/$CH_2Cl_2$ solution, to take advantage of the electronic communication between metal ion center by the conjugated backbone. The UV-visible spectroscopy (UV), mass spectrometry (MS), and cyclic voltammetry (CV) were employed to characterize the [$RuCl_2(DMSO)_2$(PhenTPy)] complex and its polymer (poly-Ru(II)Phen complex). The poly-Ru(II)Phen complex modified electrode exhibited an electrocatalytic activity to the oxidation of acetaminophen and the catalytic property was used for the analysis of acetaminophen at the concentration range between 0.09 and 0.01 mM in a phosphate buffer solution (pH 7.0).

• 분석과학
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• 제5권1호
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• pp.91-96
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• 1992

실험실에서 간단하고 값싼 교류 전압전류계를 제작하였다. 이 장치는 직류함수 발진기, lock-in 증폭기로 구성되어 있다. 1M 황산용액에서 백금을 작업전극으로 하여 $1{\times}10^{-3}M$ ${Fe(CN)_5}^{3-}$의 가역계에서 CV 전압전류곡선과 교류 전압전류곡선을 구한 데이터로부터 이 장치가 잘 작동되는 것으로 증명되었다. 요오드에 대한 정량분석 결과도 구하였다.

• 공업화학
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• 제28권5호
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• pp.506-512
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• 2017

편극화된 물/1,2-dichloroethane (1,2-DCE) 계면에서 이온화가 가능한 테트라사이클린(tetracycline, TC) 화학종 전이 반응을 순환전압전류법과 시차펄스전위법을 이용하여 조사하였다. 물의 pH 변화에 따라 전하 상태가 다른 TC 이온 화학종이 물/1,2-DCE 계면에서 전이하는 전위 값을 측정하여 TC 이온의 상 분배 도표를 얻었다. 이를 통해 각 pH에 따라 수용액 또는 유기 용액 층에서 좀 더 우세한 TC 이온 화학종 형태를 확인하였다. 이와 함께 상기 계면에서 TC 전이 반응의 형식 전이 전위, 분배 계수 및 Gibbs 에너지 값을 포함한 열역학적 정보를 얻었다. 또한 TC 이온을 정량 분석 가능한 센서로 제작하기 위해 고분자 박막에 단일 마이크로 홀을 만들고 유기성의 polyvinylchloride-2-nitrophenyloctylether (PVC-NPOE) 젤을 도포하여 물/젤 계면을 형성하였다. 물/1,2-DCE 계면에서 TC 이온의 전이 반응과 매우 유사하게 수용액의 pH가 4.0일 때 TC 이온의 농도 변화에 따라 전류 값이 증가하는 것을 순환전압전류법으로 관찰하였다. 시차펄스벗김전위법을 이용하여 상기 물/젤 계면에서 완충 수용액에 존재하는 TC 화학종을 $5{\mu}M$까지 검출할 수 있었으며, $5{\mu}M$에서 $30{\mu}M$까지 정량분석 할 수 있었다.

• Carbon letters
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• 제26권
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• pp.88-94
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• 2018

This manuscript explains the effective determination of urea by redox cyclic voltammetric analysis, for which a modified polypyrrole-graphene oxide (PPY-GO, GO 20% w/w of PPY) nanocomposite electrode was developed. Cyclic voltammetry measurements revealed an effective electron transfer in 0.1 M KOH electrolytic solution in the potential window range of 0 to 0.6 V. This PPY-GO modified electrode exhibited a moderate electrocatalytic effect towards urea oxidation, thereby allowing its determination in an electrolytic solution. The linear dependence of the current vs. urea concentration was reached using square-wave voltammetry in the concentration range of urea between 0.5 to $3.0{\mu}M$ with a relatively low limit of detection of $0.27{\mu}M$. The scanning electron microscopy was used to characterize the morphologies and properties of the nanocomposite layer, along with Fourier transform infrared spectroscopy. The results indicated that the nanocomposite film modified electrode exhibited a synergistic effect, including high conductivity, a fast electron-transfer rate, and an inherent catalytic ability.