• Journal of the Korean Chemical Society
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• v.50 no.3
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• pp.208-215
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• 2006

A simply prepared graphite, pencil-type working electrode was utilized to monitor fenitrothion concentrations, using the cyclic voltammetry (CV) and square-wave (SW) stripping voltammetry methods. The optimum conditions for analysis were sought. A very low detection limit was obtained compared to that obtained when other common voltammetry methods are used. The optimal parameters of the pencil-type electrode were found to be as follows: a pH of 3.7, a frequency of 500 Hz, an SW amplitude of 0.1 V, an increment potential of 0.005 V, an initial potential of -0.9V, and a deposition time of 500 sec. The analytical detection limit was determined to be 6.0 ngL-1 (2.16410-11 molL-1) fenitrothion at SW anodic and CV, and the relative standard deviation at the fenitrothion concentration of SW anodic 10 ugL-1 was 0.30% (n = 15) under the optimum conditions. Analysis was directly conducted through in-vivo real-time assay.

• Analytical Science and Technology
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• v.17 no.6
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• pp.464-469
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• 2004

Cyclic voltammetry was used for elucidating the electrochemical behavior of Ru-cupferron complex in 1 mM phosphate buffer. The optimal conditions of ruthenium were found to be 1 mM phosphate buffer solution (pH 6.0) containing 0.1 mM cupferron, scan rate of 100 mV/s. By using the plot on the reduction peak currents of linear scan voltammograms vs. ruthenium concentration, the detection limit ($3{\sigma}$) was $1.2{\times}10^{-7}M$.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.115-120
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• 2017

In recent, it is worldwide issued that nanoscale science and technology as a solution have supported to increase the sensing performance in carbon nanotube based biosensor system. Containing material chemistry in various nanostructures has formed their high potentials for stabilizing and activating biocatalyst as a bioreceptor for medical, food contaminants, and environmental detections using electrode modification technologies. Especially, the large surface area provides the attachment of biocatalysts increasing the biocatalyst loading. Therefore, nano-scale engineering of the biocatalysts have been suggested to be the next stage advancement of biosensors. Here, we would like to study the electrical mechanism depending on the exposure methods (soaking or dropping) to the sample solution to the assembled carbon nanotubes (CNTs) on the gold electrodes of biosensor for a simple and highly sensitive detection. We performed various experiments using polar and non-polar solutions as sampling tests and identified electrical response of assembled CNTs in those solutions.

• Journal of the Korean Chemical Society
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• v.43 no.3
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• pp.271-279
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• 1999

A new enzyme electrode was developed by co-mobilization of chicken small intestinal tissue and ferrocene in a carbon paste for the determination of hydrogen peroxide, and its electrochemical properties are evaluated. The electrode showed the response time(t100%) as short as 3 set, the detection limit of 5.0${\times}$10-5 M,and a good selectivity for the possible interferents tested. The electrode also offered a good linearity in calibration, a higher biocatalytic stability and a larger responding signal as compared with the other animal or plant tissue based sensors.

• Journal of the Korean Electrochemical Society
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• v.3 no.4
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• pp.232-234
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• 2000

Determination of uric acid by electrochemical method using ultrasonic stimulation has been investigated. Effects of sonication power, sonication time, pH of the solution and temperature were studied to obtain the optimal analytical conditions. The stability of the electrode was also examined. The optimal conditions for the sonovoltammetric determination of uric acid were as follows: temperature, $25.0^{\circ}C$ pH 7.0; sonication power, $20W/cm^2$. The calibration curve for the determination of uric acid by sono-LSV was linear over the range of$8.0{\times}10^{-6}\~5.0\times10^{-4}M$ and the limit of detection was $6.5\times10^{-6}M$.

• Korean Journal of Food Science and Technology
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• v.53 no.1
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• pp.1-11
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• 2021

In this review, recent foodborne outbreaks caused by viruses in the Republic of Korea (2010-2019) were analyzed. The human norovirus was found to be the major foodborne virus causing an average of 94.9% of the viral outbreaks. Reverse-transcription polymerase chain reaction (PCR) with electrophoresis has been widely used to detect viruses, but several rapid detection methods, including real-time PCR, multiplex PCR, and quantum dot assay, have also been suggested. For norovirus inactivation studies, surrogates such as murine norovirus and feline calicivirus have been widely used to identify the reduction rate owing to the limitations in laboratory cultivation. Conversely, direct cell infection studies have been conducted for other foodborne viruses such as adenovirus, astrovirus, rotavirus, and hepatitis A or E virus. Moreover, virucidal mechanisms using various physical and chemical treatments have been revealed. These recent studies suggest that rapid in situ detection and effective control are valuable for ensuring food safety against viral infections.

• Journal of the Korean Electrochemical Society
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• v.23 no.3
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• pp.73-80
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• 2020

Fenton oxidation method using hydrogen peroxide is an eco-friendly oxidation method used in water treatment and soil restoration. When removing pollutants by this method, it is quite important to properly regulate the concentration of hydrogen peroxide according to the concentration of the contaminants. In this study, electrochemical biosensors using HRP (horseradish peroxidase) enzymes were manufactured and studies were conducted on the activity of enzymes and the detection characteristics of hydrogen peroxide. HRP were electro deposited with chitosan and AuNP on the working electrode surface of the SPCE (Screen Printed Carbon Electrode). Then, the fixation of enzymes was confirmed using the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The activity of HRP enzymes was also identified from chronoamperometry (CA) and UV spectroscopy. After immersing the biosensor in PBS solution the current generated from electrodes by titrating hydrogen peroxide was measured from CA analysis. The generated current increased linearly for the concentration of hydrogen peroxide, and a calibration curve was derived that could predict the concentration of hydrogen peroxide from the current.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.231.2-231.2
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• 2015

본 연구에서는 나노갭 소자에 미세유체 수직 이중층을 도입하여 상층에 존재하는 금나노입자를 검출하였다. 형성된 수직 이중 층의 상층에는 검출물질을 주입하였고 하층에는 검출물질과 소자 표면의 전극을 분리 시킬 수 있는 용액을 주입하였다. 수직 이중층의 형성은 크로노암페로메트리(Chronoamperometry)을 이용하여 상층에 흘려준 electrochemical indicator 인 ferricyanide 용액의 전기화학 신호가 발생되지 않음을 통해서 확인하였다. 연속적인 수직 이중 층의 흐름에서 유전영동법을 이용하여 상층에 존재하는 금나노입자들을 나노갭전극으로 유도포획 하였고 이때 실시간으로 변하는 전류 값으로부터 금나노입자의 검출여부를 판단하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.744-745
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• 2007

변압기를 진단하는 분석 요소 중 흔히 사용하는 방법으로 유중가스분석을 이용하는 방식을 많이 사용하고 있다. 유중가스 분석은 변압기 내 Oil이 열과 Arc등에 의해 화학적으로 변화된 것을 측정하여 열화 정도를 추정하는 방식이지만 신속한 검출 및 위치추정이 불가능하다는 단점이 있다. 신속한 검출이 되지 않으면 신속한 보고가 이루어 질 수 없으므로 변압기 교체시점을 맞추지 못하여 사고로 인한 막대한 피해보상이 발생한다. 이런 단점을 보완하기 위해 변압기내 부분방전 및 Arc에 의해 발생하는 부분방전신호를 초음파 대역에서 검출하여 열화 및 위치를 추정할 수 있는 초음파 분석이 필요하게 되었고 실험을 통해 변압기에 대한 분석, 진단을 시행하였다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1536-1537
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• 2007

본 논문은 당뇨병의 지표 물질인 glucose의 농도를 극미량의 시료를 사용하여 정량할 수 있는 방법을 개발하기 위해 organic/inorganic 네트웍에 의해 안정화된 나노입자 효소를 이용하여 초소형 효소 전극을 개발하였다. 전극은 실리콘 웨이퍼상에 반도체 공정을 이용하여 마이크로 크기의 금 박막 전극을 제작하였다, Organic/Inorganic 물질과 함께 합성된 glucose oxidase 나노입자는 20nm 크기로 투과형 전자현미경 (Transmission Electron Microscope:TEM)으로 관찰하고, 푸리에변환 적외선분광법(Fourier transform infrared spectrophotometer : FTIR) 을 이용하여 분석하였고, 전극 특성을 알아보기 위해 Potentiostat/Galvanostat을 사용하여 전기 화학 실험을 하였다. 제작된 전극은 시간대 전류법으로 glucose의 농도에 따른 감도를 측정하였다. 실험결과에 따라 전극의 표면에서 발생하는 전류는 glucose의 농도에 비례함을 알 수 있었다. 또한 순환 전압전류법을 통하여 감도를 측정하였다.