• Toxicological Research
• /
• 제30권4호
• /
• pp.311-316
• /
• 2014

For the detection of trace copper to be used in medical diagnosis, a sensitive handmade carbon nanotube paste electrode (PE) was developed using voltammetry. Analytical optimized conditions were found at 0.05 V anodic peak current. In the same conditions, various common electrodes were compared using stripping voltammetry, and the PE was found to be more sharply sensitive than other common electrodes. At optimum conditions, the working ranges of $3{\sim}19{\mu}gL^{-1}$ were obtained. The relative standard deviation of $70.0{\mu}gL^{-1}$ was determined to be 0.117% (n = 15), and the detection limit (S/N) was found to be $0.6{\mu}gL^{-1}$ ($9.4{\times}10^{-9}M$). The results were applied in detecting copper traces in the kidney and the brain cells of fish.

• Archives of Pharmacal Research
• /
• 제27권1호
• /
• pp.31-34
• /
• 2004

The electrochemical behavior of doxorubicin hydrochloride was investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV). From CV and SWV studies of doxorubicin hydrochloride in the acetate buffers of various pH values, it was found that protons were involved in the reduction of the antibiotic at the $H^+/e^$- ratio at one ( $\DeltaEp/pH =-53 ∼ -61 mV at 23^{\circ}C$), proposing the electrochemical reduction of the quinone moiety in its anthraquinone aglycone. Its electrochemical behavior was pseudo-reversible in the acetate buffer of pH 3.5 by exhibiting the well-defined single cathodic and anodic waves and the ratio of $lp^a/lp^c$ at approximately one over the scan rates of 10∼100 mV/s. Fast and sensitive SWV showing a single peak of doxorubicin has been applied for its quantitative analysis using an acetate buffer of pH 3.5. A linearity was obtained when the peak currents (lp) were plotted against concentrations of doxorubicin in the range of $5.0\times10^{-7} M∼1.0\times10^{-5}$M with a detection limit of $1.0\times10^{-7}$ M.

• 대한화학회지
• /
• 제40권5호
• /
• pp.341-346
• /
• 1996

$(Cin)Cu(NO_3)_2$으로 변성된 턴소반죽전극을 제작하여 $I^-$이온을 벗김전압전류법을 이용하여 정량하였다. $I^-$이온은 변성제인 $(Cin)Cu(NO_3)_2$착물에 배위된 $NO_3^-$와 이온교환에 의해 변전극에 감응하며, 산화전위는 +0.72 V였다, $I^-$ 이온의 최적분석 조건은 다음과 같다: 농축용액의 조성은 0.1 M $KNO_3$, 농축시간은 10분, 탄소분말에 대한 변성제의 함량은 40%(w/w). 선형주사 양극벗김전압전류법(Linear Sweep Anodic Stripping Voltammetry)에 의한 $I^-$이온의 검출한계는 $1.0{\times}10^{-6}M$이며, $2.0{\times}10^{-5}M$에서 구한 상대표준편차는 ${\pm}5.5%$였다. 여러 음이온에 대하여 방해작용을 검토한 결과 $Cl^-,\;Br^-,\;C_2O_4^{2-},\;ClO_4^-$ 등은 $I^-$이온의 정량에 영향을 주지 않았지만, $SCN^-$ 이온은 $I^-$ 이온의 산화전류를 약 32% 감소시켰다.

• Korean Chemical Engineering Research
• /
• 제50권4호
• /
• pp.738-742
• /
• 2012

본 연구에서는 알루미나 나노 템플레이트(anodic alumina oxide; AAO)를 이용하여 신속하면서도 효과적으로 나노입자 및 바이오물질을 분리, 농축할 수 있는 나노필터 소자를 개발하였다. 본 연구에서 사용한 나노필터 소자는 유체의 주입 및 흐름이 가능한 미세유체채널(microfluidic channel)을 PDMS에 패터닝하였다. 위아래로 형성된 PDMS 미세유체채널 사이로, 다양한 크기의 나노 다공을 형성하고 있는 AAO 막을 삽입하여 크기에 따른 나노입자 및 바이오 물질을 분리할 수 있었다. 위아래로 PDMS 유체채널과 AAO 분리막을 집적하고, 최종적으로 아크릴레이트 플락스틱(acrylic plastic)으로 전체 소자를 고정하여 나노필터유체소자를 제작하였다. 완성된 나노필터소자를 이용하여 나노입자의 농축효율 및 은나노입자가 뭉쳐져있는 필터존(filtration zone)으로부터 뎅기 바이러스(dengue virus)를 표면증강라만(surface enhanced Raman scattering)분석법에 의해 검출할 수 있었다.

• Bulletin of the Korean Chemical Society
• /
• 제33권2호
• /
• pp.415-419
• /
• 2012

Electrochemical characteristics of nitrite ion were investigated at a poly(methylene blue)-modified glassy carbon electrode by cyclic voltammetry and differential pulse voltammetry. The poly(methylene blue)-modified glassy carbon electrode exhibited enhanced anodic signals for nitrite. The effects of key parameters on the detection of nitrite were evaluated at the modified electrode, such as pH, accumulation time, and scan rate. Under optimum condition, the chemically modified electrode can detect nitrite in the concentration range $2.0{\times}10^{-6}$ to $5.0{\times}10^{-4}$ M with the detection limit of $2.0{\times}10^{-6}$ M and a correlation coefficient of 0.999. The detection of nitrite using the chemically modified electrode was not affected by common ions such as $Na^+$, $K^+$, $Ca^{2+}$, $Cl^-$, $HPO_4^{2-}$ and $H_2PO_4^- $. The modified electrode showed good stability and reproducibility. The practical application of the present method was successfully applied to the determination of nitrite ion in cabbage samples.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.407.1-407.1
• /
• 2016

Electrochromism is defined as a phenomenon which involves persistently repeated change of optical properties between bleached state and colored state by simultaneous injection of electrons and ions, sufficient to induce an electrochemical redox process. Due to this feature, considerable progress has been made in the synthesis of electrochromic (EC) materials, improvements of EC properties in EC devices such as light shutter, smart window and variable reflectance mirrors etc. Among the variable EC materials, solid-state inorganics in particular, metal oxide semiconducting materials such as nickel oxide (NiO) have been investigated extensively. The NiO that is an anodic EC material is of special interest because of high color contrast ratio, large dynamic range and low material cost. The high performance EC devices should present the use of standard industrial production techniques to produce films with high coloration efficiency, rapid switching speed and robust reversibility. Generally, the color contrast and the optical switching speed increase drastically if high surface area is used. The structure of porous thin film provides a specific surface area and can facilitate a very short response time of the reaction between the surface and ions. The large variety of methods has been used to prepare the porous NiO thin films such as sol-gel process, chemical bath deposition and sputtering. Few studies have been reported on NiO thin films made by using sol-gel method. However, compared with dry process, wet processes that have the questions of the durability and the vestige of bleached state color limit the thin films practical use, especially when prepared by sol-gel method. In this study, we synthesis the porous NiO thin films on the fluorine doped tin oxide (FTO) glass by using sputtering and anodizing method. Also we compared electrical and optical properties of NiO thin films prepared by sol gel. The porous structure is promised to be helpful to the properties enhancement of the EC devices.

• Journal of Electrochemical Science and Technology
• /
• 제10권4호
• /
• pp.394-401
• /
• 2019

The unique study of TiO₂ sol-gel modified carbon paste electrode (CPE) nanocomposites have been developed for electrochemical sensor detecting fipronil pesticide compound. We develop the easy synthesized TiO₂ via a sol-gel method and modified in CPE which applied electrochemical system as cyclic voltammetry (CV) because the concentration is proportional with current peaks. We discover the TiO₂ optimal mass used of 0.1 g which is compared with 0.7 g carbon and 0.3 mL paraffin. It has high-current anodic (Ip_a) of 1.13×10³ μA and high-current cathodic (Ip_c) -0.96×10³ μA in scan rate of 0.5 V/s. The limit of detection (LOD) of fipronil has been determined of 34.0×10^-5 μM in percent recovery of 0.8%. Its high-stability for lifetime TiO₂-CPE nanocomposites was expressed for 13 days which mean that can be used for detecting fipronil pesticide.

• 센서학회지
• /
• 제22권2호
• /
• pp.144-149
• /
• 2013

In this research, we developed a biosensor to detect lung cancer-specific biomarker using Anodic Aluminum Oxide (AAO) chip based on interference and nano surface plasmon resonance (nanoSPR). The nano-porous AAO chip was fabricated $2{\mu}m$ of pore-depth by two-step anodizing method for surface uniformity. NanoSPR has sensitivity to the refractive index (RI) of the surrounding medium and also provides simple and label-free detection when specific antibodies are immobilized to the Au-deposited surface of nano-porous AAO chip. To detect the lung cancer-specific biomarker, antibodies were immobilized on the surface of the chip by Self Assembled Monolayer (SAM) method. Since then lung cancer-specific biomarker was applied atop the antibodies immobilized layer. The specific reaction of the antigen-antibody contributed to the change in the refractive index that cause shift of resonance spectrum in the interference pattern. The Limit of Detection (LOD) was 1 fg/ml by using our nano-porous AAO biosensor chip.

• Bulletin of the Korean Chemical Society
• /
• 제29권5호
• /
• pp.915-920
• /
• 2008

In this paper the electrochemical behaviors of hydroquinone ($H_2Q$) were investigated on a carbon paste electrode using room temperature ionic liquid N-butylpyridinium hexafluorophosphate ($BPPF_6$) as binder (ILCPE) and further applied to $H_2Q$ determination. In pH 2.5 phosphate buffer solution (PBS), the electrochemical response of H2Q was greatly improved on the IL-CPE with a pair of well-defined quasi-reversible redox peaks appeared, which was attributed to the electrocatalytic activity of IL-CPE to the $H_2Q$. The redox peak potentials were located at 0.340 V (Epa) and 0.240 V (Epc) (vs. the saturated calomel electrode, SCE), respectively. The formal potential ($E^0$') was calculated as 0.290 V and the peak-to-peak separation (${\Delta}E_p$) was 0.100 V. The electrochemical parameters of $H_2Q$ on the IL-CPE were further calculated by cyclic voltammetry. Under the selected conditions the anodic peak current was linear with $H_2Q$ concentration over the range from $5.0\;{{\times}}\;10^{-6}$ to $5.0\;{\times}\;10^{-3}\;mol\;L^{-1}$ with the detection limit as $2.5\;{\times}\;10^{-6}\;mol\;L^{-1}$ (3$\sigma$ ) by cyclic voltammetry. The proposed method was successful applied to determination of $H_2Q$ content in a synthetic wastewater sample without the interferences of commonly coexisting substances.

• 분석과학
• /
• 제20권4호
• /
• pp.289-295
• /
• 2007

사각파형 벗김 전압 전류법과 순환 전압 전류법에서 적외선 광 다이오드의 간단한 전자 회로를 사용한 철의 정량을 연구하였다. 기존에 사용되는 작업 전극과 최적 분석 조건을 비교하였으며, 순환 전압 전류법의 결과는 보다 간단하며 정밀하였으며, 최적 조건에서 농도 범위는 0.1-0.8과 0.85-6.0 mg/L 이었다, 0.4 mg/L의 철 농도에서 15번 반복 측정한 상대 표준편차는 0.09%였으며, 최소 분석 검출 한계는 $80{\pm}0.6{\mu}g/L$ 였다, 이결과는 폐수중의 철 정량에 응용하였다.