• 대한약리학회지
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• 제27권1호
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• pp.7-12
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• 1991

쥐(태령 14일) 뇌간 세포배양에서 발달과정에 따른 Tyrosine hydroxylase(TH) 활성 및 dopamine의 양적 증가를 전기화학 HPLC를 이용하여 측정하였다. TH 활성 및 dopamine의 양은 배양 7일까지 점차 증가하였다. 배양 7일째에 여러 약물들의 dopamine 대사에 대한 영향을 조사하였다. TH 억제제인 ${\alpha}-methyl-p-tyrosine$ 및 aromatic amiono acid decarboxylase 억제제인 NSD-1015는 효과적으로 dopamine을 고갈시켰다. Dopamine은 reserpine에 의해 고갈되었고, parglyine에 의해 증가되었다. 일주일 배양한 세포의 배양액에 tetrodotoxin$(0.1\;{\mu}M$)을 7일간 투여하였을 때 TH 활성은 현저히 감소하였다. 이상의 결과들은 배양세포의 dopamine 대사가 뇌 dopamine 대사를 충실히 반영함을 나타낸다. 뇌간 세포의 배양에서 HPLC-전기화학검출을 이용한 TH 활성 및 dopamine의 측정은 중추 dopamine계의 약리 및 독성 연구에 유용하리라 사료된다.

• Carbon letters
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• 제23권
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• pp.38-47
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• 2017

In this study, magnetite ($Fe_3O_4$) nanoparticles were electrochemically synthesized in an aqueous electrolyte at a given potential of -1.3 V for 180 s. Scanning electron microscopy revealed that dendrite-like $Fe_3O_4$ nanoparticles with a mean size of < 80 nm were electrodeposited on a glassy carbon electrode (GCE). The $Fe_3O_4/GCE$ was utilized for sensing chloramphenicol (CAP) by cyclic voltammetry and square wave voltammetry. A reduction peak of CAP at the $Fe_3O_4/GCE$ was observed at 0.62 V, whereas the uncoated GCE exhibited a very small response compared to that of the $Fe_3O_4/GCE$. The electrocatalytic ability of $Fe_3O_4$ was mainly attributed to the formation of Fe(VI) during the anodic scan, and its reduction to Fe(III) on the cathodic scan facilitated the sensing of CAP. The effects of pH and scan rate were measured to determine the optimum conditions at which the $Fe_3O_4/GCE$ exhibited the highest sensitivity with a lower detection limit. The reduction current for CAP was proportional to its concentration under optimized conditions in a range of $0.09-47{\mu}M$ with a correlation coefficient of 0.9919 and a limit of detection of $0.09{\mu}M$ (S/N=3). Moreover, the fabricated sensor exhibited anti-interference ability towards 4-nitrophenol, thiamphenicol, and 4-nitrobenzamide. The developed electrochemical sensor is a cost effective, reliable, and straightforward approach for the electrochemical determination of CAP in real time applications.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.100-103
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• 2003

Signal detection technologies such as fluorescence, charge and electrochemical detection used in the monolithic capillary electrophoresis system to convert the biochemical reaction into the electrical signal. The fluorescence detection using photodiodes that measure fluorescence emitted from eluting molecules is widely used for the monolithic capillary electrophoresis system. In this paper, in order to fabricate a photosensor has the increased sensitivity, we investigated on the sensitivity of general type and p-i-n type diode. The p-i-n diode has higher sensitivity than photodiode. Considering these results, we fabricated p-i-n diodes on the high resistive$(4k{\Omega}{\cdot}cm)$ wafer into rectangle and finger pattern and compared internal resistance of each pattern. The internal resistance of p-i-n diode can be decreased by the application of finger pattern has parallel resistance structure from $571{\Omega}$ to $393{\Omega}$.

• Bulletin of the Korean Chemical Society
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• 제31권1호
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• pp.140-145
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• 2010

The simultaneous detection of Cd (II), Pb (II), Cu (II), and Hg (II) ions in aqueous medium using a BDD electrode with DPASV is described. XPS was used to characterize the chemical states of trace metal ions deposited on the BDD electrode surface. Experimental parameters that affect response, such as pH, deposition time, deposition potential, and pulse amplitude were carefully optimized. The detection limits for Cd (II), Pb (II), Cu (II), and Hg (II) ions were 3.5 ppb, 2.0 ppb, 0.1 ppb and 0.7 ppb, respectively. The application of the BDD electrode on the electrochemical pretreatment for the simultaneous metal detection in the dye waste water was also investigated.

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.833-837
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• 2004

DeniLite$^{TM}$ laccase immobilized platinum electrode was used for amperometric detection of hydroquinone (HQ) and homogentisic acid (HGA) by means of substrate recycling. In case of HQ, the obtained sensitivity is 280 nA/ ${\mu}$M with linear range of 0.2-35 ${\mu}$M ($r^2$ = 0.998) and detection limit (S/N = 3) of 50 nM. This high sensitivity can be attributed to chemical amplification due to the cycling of the substrate caused by enzymatic oxidation and following electrochemical regeneration. In case of HGA, the obtained sensitivity is 53 nA/ ${\mu}$M with linear range of 1-50 $[\mu}M\;(r^2$ = 0.999) and detection limit of 0.3 ${\mu}$M. The response times ($t_{90%}$) are about 2 seconds for the two substrates and the long-term stability is 60 days for HQ and around 40-50 days for HGA with retaining 80% of initial activities. The very fast response and the durable long-term stability are the principal advantages of this sensor. pH studies show that optimal pH of the sensor for HQ is 6.0 and that for HGA is 4.5-5.0. This shift of optimal pH towards acidic range for HGA can be attributed to the balance between enzyme activity and accessibility of the substrate to the active site of the enzyme.

• Mass Spectrometry Letters
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• 제13권4호
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• pp.95-105
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• 2022

Amatoxin-induced mushroom poisoning starts with nonspecific symptoms of toxicity but hepatic damage may follow, resulting in the rapid development of liver insufficiency and, ultimately, coma and death. Accurate detection of amatoxins, such as α-, β-, and γ-amanitin, within the first few hours after presentation is necessary to improve the therapeutic outcomes of patients. Therefore, analytical methods for the identification and quantification of α-, β-, and γ-amanitin in biological samples are necessary for clinical and forensic toxicology. This study presents a literature review of the analytical techniques available for amatoxin detection in biological matrices, and established an inventory of liquid chromatography (LC) techniques with mass spectrometry (MS), ultraviolet (UV) detection, and electrochemical detection (ECD). LC-MS methods using quadrupole tandem mass spectrometry, time-of-flight mass spectrometry, and orbitrap MS are powerful analytical techniques for the identification and determination of amatoxins in plasma, urine, serum, and tissue samples, with high sensitivity, specificity, and reproducibility compared to LC with UV and ECD, enzyme-linked immunoassay, and capillary electrophoresis methods.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권4호
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• pp.133-136
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• 2004

This research aims to develop a DNA chip array without an indicator. We fabricated a microelectrode array through photolithography technology. Several DNA probes were immobilized on an electrode. Then, target DNA was hybridized and measured electrochemically. Cyclic-voltammograms (CVs) showed a difference between the DNA probe and mismatched DNA in an anodic peak. This indicator-free DNA chip resulted in a sequence-specific detection of the target DNA.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4219-4222
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• 2012

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1322-1323
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• 2006

This research aims to develop the multiple channel electrochemical DNA chip that has the above characteristic and be able to solve the problems. At first, we fabricated a high integration type DNA chip array by lithography technology. It is able to detect a plural genes electrochemically after immobilization of a plural probe DNA and hybridization of non-labeling target DNA on the electrodes simultaneously.

• 전기화학회지
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• 제19권2호
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• pp.29-38
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• 2016

전기화학적 방법을 통한 요산 (Uric acid) 정량분석을 위해 수용성 고분자 (hydrogel polymer)를 배위시킨 오스뮴 고분자 화합물과 요산 산화효소 (Uricase), 가교를 위한 PEGDGE (poly(ethylene glycol) diglycidyl ether)가 혼합된 용액을 스크린 프린팅된 탄소 전극 (SPCEs) 위에 흡착하여 측정하였다. 수용성 오스뮴 고분자의 전위를 조절하기 위해 리간드인 피리딘링의 4번 위치에 다른 전기음성도의 작용기를 갖는 오스뮴 고분자 화합물을 합성하였다. 합성된 오스뮴 고분자 화합물은 PAA-PVI (Poly(acrylic acid)-poly(vinyl imidazole)-$[osmium(4,4^{\prime}-dichloro-2,2^{\prime}-bipyridine)_2Cl]^{+/2+}$), PAA-PVI-$[osmium(4,4^{\prime}-dimethyl-2,2^{\prime}-bipyridine)_2Cl]^{+/2+}$, PAA-PVI-$[osmium(4,4^{\prime}-dimethoxy-2,2^{\prime}-bipyridine)_2Cl]^{+/2+}$이다. 제작된 효소전극은 순환전압전류법 (cyclic voltammetry)을 통해 uric acid에 의한 오스뮴 고분자 화합물들의 산화 촉매 전류(oxidation catalytic current)를 측정하여 uric acid의 농도를 정량적으로 분석할 수 있었다. 오스뮴 고분자 화합물들 중 0.215 V의 산화환원 전위를 갖는 $PAA-PVI-[Os(dme-bpy)_2Cl]^{+/2+}$ (PAA-PVI-osmium$(4,4^{\prime}-dimethyl-2,2^{\prime}-bipyridine)_2Cl$]$^{+/2+}$) 화합물을 이용하여 대표적인 간섭물질인 아스코르브산 (AA)과 포도당 (glucose)의 산화 신호의 간섭효과를 피할 수 있었다. 이를 이용하여 제작된 전극은 0.33 V 전위에서 다양한 농도의 uric acid (1.0, 1.5, 2.0, and 5.0 mM)의 전류를 측정한 결과 $r^2=0.9986$의 좋은 선형성을 갖는 것을 확인하였다. 이는 복잡하지 않은 간단한 방법과 일회용의 전극을 사용하기 때문에 현장현시 검사 (point of care; POC)에 적합한 요산측정용 바이오센서로서의 가능성을 확인 할 수 있었다.