• 대한화학회지
• /
• 제43권3호
• /
• pp.264-270
• /
• 1999

Immobilon-AV 친화성 막에 glucose oxidase[EC1.1.3.4](725units/mL)를 고정하여 백금 전극에 부착시킨 전극을 사용하여 glucose를 전류법으로 정량하였다. 이때 glucose가 gluconic acid로 산화될 때 전류를 +0.8V vs. Ag/AgC1에서 측정하였다. 효소 고정화된 막을 부착시킨 전극의 감응 특성은 다음과 같다. 직선 감응범위는 0.2mM에서 20mM이었으며, 정량한계는 10-3 mM이었다. 또한 감응 시간은 12초, 효소 고정화된 막의 최적 pH(CH3COONa/CH3COOH)는 5.5, 그리고 수명은 27일 이였다. 그리고 다른 생리 활성물질의 방해는 없었다. 또한 고구마를 이용하여 AOAC 방법으로 정량한 glucose 측정값을 비교해 본 결과, 그 상대오차는 0.1%였다.

• 전기화학회지
• /
• 제7권2호
• /
• pp.83-88
• /
• 2004

[ $DeniLite^{TM}$ ] laccase immobilized Pt electrode was used for amperometric detection of some catechol derivatives and o-aminophenol (OAP) derivative by means of substrate recycling. In case of catechol derivatives, the obtained sensitivities are 85, 79 and $57 nA/{\mu}M$ with linear ranges of $0.6\~30,\;0.6\~30\;and\; 1\~25 {\mu}M$ and detection limits (S/N=3) of 0.2, 0.2 and $0.3{\mu}M$ for 3,4-dihydroxycinnaminic acid (3,4-DHCA), 3,4-dihydroxybenzoic acid (3,4-DHBA) and 3,4-dihydroxyphenylacetic acid (3,4-DHPAA), respectively. In case of OAP derivative, the obtained sensitivity is $237 nA/{\mu}M$ with linear range of $0.2\~15{\mu}M$ and detection limit of 70 nM for 2-amino-4-chlorophenol (2-A-4-CP). The response time $(t_{90\%})$ is about 2 seconds for each substrate and the long-term stability is around 40-50days for catechol derivatives and 30 days for 2-A-4-CP with retaining $80\%$ of initial activity. The optimal pHs of the sensor for these substrates are in the range of 4.5-5.0, which indicates that stability of the enzymatically oxidized product plays a very important role in substrate recycling. The different sensitivity of the sensor for each substrate can be explained by the electronic effect of the sugstituent on the enzymatically oxidized form.

• 대한화학회지
• /
• 제57권3호
• /
• pp.329-334
• /
• 2013

솔잎조직과 ferrocene을 각각 효소원 및 매개체로, CSM 고무를 흑연가루 결합재로 사용하여 전류법 과산화수소 정량 효소전극을 제작하고, 그것의 특성을 전기화학적인 방법으로 관찰하였다. 낮은 퍼텐샬 영역(-100 ~ -500 mV)에서 보여준 ln($i(1-e^{nf{\eta}})$) vs. ${\eta}$ 및 Lineweaver-Burk 도시의 좋은 직선성은 신호전류의 생성이 효소의 촉매작용에 의한 것임을 확인하여 주었다. 이 때 얻어진 대칭인자(${\alpha}$, 0.17), 한계전류($i_1$, 1.99 $A/cm^2$), 교환전류밀도($i_0$, $5.86{\times}10^{-5}\;A/cm^2$), 마이클 상수($K_M$, $1.68{\times}10^{-3}$ M) 및 기타 전극 파라메터들은 전극 표면에서 소나무 과산화효소가 정량적으로 성능을 발휘하고 있음을 보여 주었다. 이런 실험적 사실들은 솔잎조직이 상업용 과산화효소를 대치하여 실용 효소전극 제작에 사용될 수 있음을 보여 주었다.

• Bulletin of the Korean Chemical Society
• /
• 제27권1호
• /
• pp.65-70
• /
• 2006

An amperometric glucose biosensor has been developed based on the use of the nanoporous composite film of sol-gel-derived zirconia and perfluorosulfonated ionomer, Nafion, for the encapsulation of glucose oxidase (GOx) on a platinized glassy carbon electrode. Zirconium isopropoxide (ZrOPr) was used as a sol-gel precursor for the preparation of zirconia/Nafion composite film and the performance of the resulting glucose biosensor was tuned by controlling the water content in the acid-catalyzed hydrolysis of sol-gel stock solution. The presence of Nafion polymer in the sol-gel-derived zirconia in the biosensor resulted in faster response time and higher sensitivity compared to those obtained at the pure zirconia- and pure Nafion-based biosensors. Because of the nanoporous nature of the composite film, the glucose biosensor based on the zirconia/Nafion composite film can reach 95% of steady-state current less than 5 s. In addition, the biosensor responds to glucose linearly in the range of 0.03-15.08 mM with a sensitivity of 3.40 $\mu$A/mM and the detection limit of 0.037 mM (S/N = 3). Moreover, the biosensor exhibited good sensor-to-sensor reproducibility (~5%) and long-term stability (90% of its original activity retained after 4 weeks) when stored in 50 mM phosphate buffer at pH 7 at 4 ${^{\circ}C}$.

• 대한화학회지
• /
• 제37권6호
• /
• pp.604-611
• /
• 1993

초임계 유체 크로마토그래피(Supercritical Fluid Chromatography, SFC)는 종래의 크로마토그래피 방법으로 분석하기 어려운 물질을 분석해 내는 기술로써 발전이 되어왔다. 그러나, SFC에서 이동상으로 많이 사용되고 있는 초임계 C$O_2$는 용매로써 특성이 n-hexane과 매우 비슷하여 극성이 큰 시료들을 용출(elution)시키기가 어렵다. 이러한 점을 해결하기 위하여 초임계 C$O_2$에 극성을 지닌 물질 즉, 변형제(modifier)를 섞어서 이동상으로 사용할 수 있다. 본 연구에서는 초임계 C$O_2$에 변형제를 첨가시키는 새로운 방법을 개발하였고, 변형제로써 초임계 C$O_2$에 첨가된 수분(H$_2O$)의 양을 perfluorosulfonate ionomer(PFSI) film을 이용해 만든 amperometric microsensor로써 측정하였다. 이와같은 방법을 사용함으로써 포화 column보다 상당히 긴 시간동안 일정하게 수분을 첨가할 수 있었고, 실제로 이 방법을 사용하여 순수한 C$O_2$ 이동상만으로는 분리하기 어려운 몇 가지 살균제와 살충제에 적용한결과 좋은 크로마토그램을 얻었다.

• 폴리머
• /
• 제38권6호
• /
• pp.809-814
• /
• 2014

전류 감응형 바이오센서에 응용하기 위해 전도성 고분자 마이크로튜브 어레이를 제작하였다. Poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonic acid)(PEDOT/PSS) composite을 전도성 접착제로 하여 템플릿을 전극에 고정한 후 EDOT을 전기화학적으로 중합하였다. 마이크로튜브 어레이는 자체의 넓은 표면적으로 인해 감도 높은 바이오센서로 응용될 수 있으나, 주요 표적물질 중의 하나인 과산화수소에 대한 전기화학적 반응이 느렸다. 과산화수소 산화에 대한 감도를 향상시키기 위해 어레이 전극에 금을 도포하였다. 증착법과 전기화학적 석출법 두 가지 방법을 시도하여 금을 처리하였는데, 이렇게 처리한 전극은 모두 과산화수소에 대한 반응이 크게 향상되었다. 따라서 전도성 고분자 마이크로튜브 어레이에 금을 도포함으로써 과산화수소를 표적물질로 하는 감도 높은 바이오센서 제작이 가능할 것으로 기대된다.

• Journal of Electrochemical Science and Technology
• /
• 제9권1호
• /
• pp.28-36
• /
• 2018

Metal-organic frameworks have recently been considered very promising modifiers in electrochemical analysis due to their unique characteristics among which tunable pore sizes, crystalline ordered structures, large surface areas and chemical tenability are worth noting. In the present research, $Cu(btec)_{0.5}DMF$ was electrodeposited on the surface of glassy carbon electrode at room temperature under cathodic potential and was initially used as the active materials for the detection of $H_2O_2$. The cyclic voltammogram of $Cu(btec)_{0.5}DMF$ modified GC electrode shows distinct redox peaks potentials at +0.002 and +0.212 V in 0.1 M phosphate buffer solution (pH 6.5) corresponding to $Cu^{(II)}/Cu^{(I)}$ in $Cu(btec)_{0.5}DMF$. Acting as the electrode materials of a non-enzymatic $H_2O_2$ biosensor, the $Cu(btec)_{0.5}DMF$ brings about a promising electrocatalytic performance. The high electrocatalytic activity of the $Cu(btec)_{0.5}DMF$ modified GC electrode is demonstrated by the amperometric response towards $H_2O_2$ reduction with a wide linear range from $5{\mu}M$ to $8000{\mu}M$, a low detection limit of $0.865{\mu}M$, good stability and high selectivity at an applied potential of -0.2 V, which was higher than some $H_2O_2$ biosensors.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
• /
• pp.2410-2412
• /
• 2005

In this study, two types of PS substrate were fabricated for sensing of chemical and biological substances. For sensing of the humidity and chemical analyzes such as $CH_3OH$ or $C_2H_5OH$, PS layers are prepared by photoelectrochemical etching of silicon wafer in aqueous hydrofluoric acid solution. To evaluate their sensitivity, we measured the resistance variation of the PS diaphragm. As the amplitude of applied voltage increases from 2 to 6Vpp at constant frequency of 5kHz, the resistance variation for humidity sensor rises from 376.3 to $784.8{\Omega}$/%RH. And the sensitivities for $CH_3OH$ and $C_2H_5OH$ were 0.068 uA/% and 0.212 uA/%, respectively. For biological sensing application, amperometric urea sensors were fabricated based on porous silicon(PS), and planar silicon(PLS) electrode substrates by the electrochemical methods. Pt thin film was sputtered on these substrates which were previously formed by electrochemical anodization. Poly (3-methylthiophene) (P3MT) were used for electron transfer matrix between urease(Urs) and the electrode phase, and Urs also was by electrochemically immobilized. Effective working area of these electrodes was determined for the first time by using $Fe(CN)_6^{3-}/Fe(CN)_6^{4-}$ redox couple in which nearly reversible cyclic voltammograms were obtained. The $i_p$ vs $v^{1/2}$ plots show that effective working electrode area of the PS-based Pt thin film electrode was 1.6 times larger than the PLS-based one and we can readily expect the enlarged surface area of PS electrode would result in increased sensitivity by ca. 1.6 times. Actually, amperometric sensitivity of the Urs/P3MT/Pt/PS electrode was ca 0.91uA/$mM{\cdot}cm^2$, and that of the Urs/P3MT/Pt/PLS electrode was ca. 0.91uA/$mM{\cdot}cm^2$ in a linear range of 1mmol/L to 100mmol/L urea concentrations

• Journal of Electrochemical Science and Technology
• /
• 제14권3호
• /
• pp.252-261
• /
• 2023

Glucose detection is particularly important for clinical diagnosis and personal prevention and control. Herein, the smartphone-based amperometric glucose sensors were constructed using the NiS/CuS nanorods (NRs) as sensing electrodes. The NiS/CuS NRs were prepared through a facile hydrothermal process accompanied by the subsequent vulcanization treatment. The morphological and structural properties of NiS/CuS NRs were characterized with SEM, EDS, XRD, and XPS. Electrochemical measurements including cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy display that NiS/CuS NRs can act as highly efficient electrocatalyst for glucose detection. The NiS/CuS NRs electrodes present a wide detection range of 1-8000 µM for glucose sensing with the sensitivity of 956.38 µA·mM^-1·cm^-2. The detection limit was 0.35 µM (S/N=3). When employed in smartphone-based glucose sensing device, they also display a high sensitivity of 738.09 µA·mM^-1·cm^-2 and low detection limit of 1.67 µM. Moreover, the smartphone-based glucose sensing device also presents favorable feasibility in determination of glucose in serum samples with the recoveries ranging between 99.5 and 105.8%. The results may provide a promising viewpoint to design other new portable glucose sensors.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.251-252
• /
• 2009

전류에 의한 자속변화를 검출하는 로고스키코일은 자성체를 코어로 이용하는 종전의 변류기 (Current Transformer) 와는 달리 공심이거나 비자성재료를 사용하기 때문에 자기적으로 포화되지 않으므로 일반적으로 디지털 적산 전력량계의 전류센서로 활용되고 있다. 본 연구는 저온소성 다층 세라믹 기판상에 로고스키코일을 적용한 전자식 전력량계의 정밀 전류측정용 센서 개발에 관한 것이며. 3차원 전자기장 해석 프로그램인 MWS를 하여 기판의 소재와 코일의 패턴의 크기 등을 달리하여 그 특성을 알아보고 실제 구현된 센서의 측정된 값과 비교해 보았다.