• 센서학회지
• /
• 제21권3호
• /
• pp.229-234
• /
• 2012

The existing permeability measurements based on pressure differential between the polymer membrane that is permeable to measure the amount of oxygen used, but these methods must be kept in a vacuum, and the measurement of the membrane with low permeability in the membrane is too time consuming. In recent years by using electrochemical method polymer membrane currents caused by the amount of oxygen is a measure of how much is used. In this study, apparatus consisting of one anode and six cathodes for multi-oxygen permeability tester used the same number of membranes produced by electrochemical oxygen permeation characteristics. In this study, one silver/silver chloride anode electrochemical method with a hexagonal sensor to put various kinds of polymer membranes with the six oxygen permeability for simultaneous measurement in real-time systems. Six cathodes (Pt), and one of the coil-shaped anode (Ag/AgCl) to form a hexagonal one of the polarographic oxygen sensor in a single measurement system by six sensors. Each sensor for making hexagonal specificity of the sensor to compensate for the conditions obtained in a pure nitrogen gas and pure oxygen gas conditions. With this study, self-developed hexagonal sensor capable of measuring sensors and oxygen permeability tester, for a multi-six different oxygen permeability characteristics of the membrane measured at the same time.

• Journal of Microbiology and Biotechnology
• /
• 제18권1호
• /
• pp.145-152
• /
• 2008

A cell-based in vitro exposure system was developed to determine whether oxidative stress plays a role in the cytotoxic effects of volatile organic compounds (VOCs) such as benzene, toluene, xylene, and chlorobenzene, using human epithelial HeLa cells. Thin films based on cysteine-terminated synthetic oligopeptides were fabricated for immobilization of the HeLa cells on a gold (Au) substrate. In addition, an immobilized cell-based sensor was applied to the electrochemical detection of the VOCs. Layer formation and immobilization of the cells were investigated with surface plasmon resonance (SPR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The adhered living cells were exposed to VOCs; this caused a change in the SPR angle and the VOC-specific electrochemical signal. In addition, VOC toxicity was found to correlate with the degree of nitric oxide (NO) generation and EIS. The primary reason for the marked increase in impedance was the change of aqueous electrolyte composition as a result of cell responses. The p53 and NF-${\kappa}B $ downregulation were closely related to the magnitude of growth inhibition associated with increasing concentrations of each VOC. Therefore, the proposed cell immobilization method, using a self-assembly technique and VOC-specific electrochemical signals, can be applied to construct a cell microarray for onsite VOC monitoring.

• Korean Chemical Engineering Research
• /
• 제61권1호
• /
• pp.52-57
• /
• 2023

본 연구는 고성능 유연 전극 소재 개발을 위한 기초 연구로, 유연 전극 소재의 성능을 향상시키기 위해 금속 산화물 CuO nanoparticles (CuO NPs)를 도입하여 탄소나노튜브 섬유(carbon nanotube fiber; CNT fiber) 표면 위에 전기화학적 증착시켜 CNT fiber/CuO NPs 전극을 합성하고, 이를 전기화학적 비효소 글루코스 센서에 적용하였다. 이 전극의 표면 및 elemental composition 분석은 주사전자 현미경(SEM)과 에너지분산형 분광분석법(EDS)을 이용하였으며, 전극의 전기화학적 특성 및 글루코스에 대한 센싱 성능은 순환전압 전류법(CV)과 전기화학 임피던스법(EIS), 시간대전류법(CA)을 통해 조사되었다. CNT fiber/CuO NPs 전극은 CNT fiber의 우수한 특성과 함께 CuO NPs 도입에 따른 약 2.6배의 유효 전극면적(active surface area) 증가 효과와 11배 정도의 향상된 전자전달(electron transfer) 특성 및 우수한 전기적 촉매 활성(electrocatalytic activity) 덕분에 CNT fiber 유연 기반 전극의 글루코스 검출에 대한 성능이 개선되었다. 따라서, 본 연구를 기반으로 다양한 나노구조체를 활용한 고성능 유연 전극 소재 개발이 기대된다.

• Korean Chemical Engineering Research
• /
• 제62권3호
• /
• pp.233-237
• /
• 2024

본 연구는 유/무기 나노복합체를 이용한 PAN계 탄소섬유 토우(PAN-based carbon fibers tow) 기반의 유연 전극 제작 및 이를 활용한 비효소 전기화학 센서 개발에 대한 것으로, 전도성 고분자 polyaniline (PANI)와 금속 산화물 CuO을 유/무기 나노복합체 소재로 사용하였으며 글루코스를 전기화학 센서 타겟으로 적용하였다. 전극 제작을 위해 시판된 CFT는 열처리를 통한 사이징(sizing) 제거와 전기화학적 산화에 의한 표면 활성화의 전처리 공정을 거쳐 사용되었다. 유/무기 나노복합체는 전기화학적 중합 및 증착법을 통해 전처리된 CFT 표면 위에 순차적으로 합성되어 최종 CFT/PANI/CuO NPs 전극이 제작되었다. CFT/PANI/CuO NPs 전극의 전기화학적 특성 및 센싱 성능은 시간대전류법와 순환전압 전류법, 전기화학 임피던스 분광법을 이용하여 분석되었다. CFT/PANI/CuO NPs 전극은 전도성 고분자과 금속 산화물의 접목에 의해 전기 전도도 향상 및 우수한 전자 전달, 감응시간 단축, 비표면적 증가 등 개선된 전기화학적 특성과 증가된 감도, 넓은 선형 농도 구간, 높은 선택도 등 향상된 글루코스 센싱 성능을 보였다.

• Bulletin of the Korean Chemical Society
• /
• 제29권11호
• /
• pp.2097-2102
• /
• 2008

• 대한전기학회논문지
• /
• 제45권1호
• /
• pp.93-99
• /
• 1996

The formation properties and oxidation mechanism of electrochemically oxidized porous silicon(OPS) films have been studied. To examine the humidity-sensitive properties of OPS films, surface-type and bulk-type humidity sensors were fabricated. The oxidized thickness of porous silicon layer(PSL) increases with the charge supplied during electrochemical humidity sensor shows high sensitivity at high relative humidity in low temperature. The sensitivity and linearity can be improved by optimizing a porosity of PSL. (author). refs., figs.

• 센서학회지
• /
• 제15권2호
• /
• pp.127-133
• /
• 2006

Recent studies demonstrated the ability of carbon nanotube (CNT) to promote electron transfer reactions of important compounds and to impart higher stability onto electrochemical sensors. CNT-based sensors measured by hydroxyl radical concentration or pH value suggest great promise for biosensors. This paper describes a new method for fabricating a very simple and inexpensive pH sensor compose of single walled-carbon nanotubes (SW-CNTs) using an ultra-precision spray. CNT-based sensor shows pH sensitivity in buffer solution at different pH range. Our experimental results show the sensor responses to pH buffer solution and the conductance of depends on the pH values. These results support application possibility of SW-CNTs based pH sensor for mass production.

• Journal of Electrochemical Science and Technology
• /
• 제14권1호
• /
• pp.66-74
• /
• 2023

In this study, a new potentiometric sensor selective to copper(II) ions was developed and characterized. The developed sensor has a polymeric membrane and contains 4.0% electroactive material (ionophore), 33.0% poly(vinyl chloride) (PVC), 63.0% bis(2-ethylhexyl)sebacate (BEHS) and 1.0% potassium tetrakis(p-chlorophenyl)borate (KTpClPB). This novel copper(II)-selective sensor exhibits a Nernstian response over a wide concentration range from 1.0×10^-6 to 1.0×10^-1 mol L^-1 with a slope of 29.6 (±1.2) mV decade^-1, and a lower detection limit of 8.75×10-7 mol L^-1. The sensor, which was produced economically by synthesizing the ionophore in the laboratory, has a good selectivity and repeatability, fast response time and stable potentiometric behaviour. The potential response of the sensor remains unaffected of pH in the range of 5.0-10.0. Based on the analytical applications of the sensor, we showed that it can be used as an indicator electrode in the quantification of Cu²⁺ ions by potentiometric titration against EDTA, and can also be successfully utilized for the determination of copper(II) ions in different real samples.

• 전기화학회지
• /
• 제17권1호
• /
• pp.18-25
• /
• 2014

A Pt nanoparticle-decorated multiwall carbon nanotube (Pt-MWNT) electrode was prepared on Nafion by a hot-pressing at relatively low temperature. This electrode exhibited an intricate entangled, nanoporous structure as a result of gathering highly anisotropic Pt-MWNTs. Individual Pt nanoparticles were confirmed to have a polycrystalline face-centered cubic structure with an average crystal size of around 3.5 nm. From the cyclic voltammograms for hydrogen redox reactions, the Pt-MWNT electrode was found to have a similar electrochemical behavior to polycrystalline Pt, and a specific electrochemical surface area of $2170cm^2mg^{-1}$. Upon exposure to hydrogen analyte, the Pt-MWNT/Nafion electrode demon-strated a very high sensitivity of $3.60{\mu}A\;ppm^{-1}$ and an excellent linear response over the concentration range of 100-1000 ppm. Moreover, this electrode was also evaluated in terms of response and recovery times, reproducibility, and long-term stability. Obtained results revealed good sensing performance in hydrogen detection.

• Journal of Electrochemical Science and Technology
• /
• 제11권1호
• /
• pp.68-83
• /
• 2020

A fast and simple method for synthesis of Cu_xO-ZnO/PPy/RGO nanocomposite by electrochemical manner have been reported in this paper. For testing the utility of this nanocomposite we modified a GCE with the nanocomposite to yield a sensor for simultaneous determination of four analytes namely ascorbic acid (AA), dopamine (DA), uric acid (UA), and folic acid (FA). Cyclic voltammetry (CV) and Differential pulse voltammetry (DPV) selected for the study. The modified electrode cause to enhance electron transfer rate so overcome to overlapping their peaks and consequently having the ability to the simultaneous determination of AA, DA, UA, and FA. To synthesis confirmation of the nanocomposite, Field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, and electrochemical impedance spectroscopy (EIS) were applied. The linearity ranges were 0.07-485 μM, 0.05-430 μM, 0.02-250 μM and 0.022-180 μM for AA, DA, UA, and FA respectively and the detection limits were 22 nM, 10 nM, 5 nM and 6 nM for AA, DA, UA, and FA respectively Also, the obtained electrode can be used for the determination of the AA, DA, UA, and FA in human blood, and human urine real samples.