• Title/Summary/Keyword: Chemical Detection

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Avidin Induced Silver Aggregation for SERS-based Bioassay

  • Sa, Youngjo;Chen, Lei;Jung, Young Mee
    • Bulletin of the Korean Chemical Society
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    • v.33 no.11
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    • pp.3681-3685
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    • 2012
  • We developed a simple and effective method for the SERS-based detection of protein-small molecule complexes and label-free proteins using avidin-induced silver aggregation. Upon excitation with light of the appropriate wavelength (633 and 532 nm), the aggregated silver nanoparticles generate a strong electric field that couples with the resonance of the molecules (atto610 and cytochrome c), increasing the characteristic signals of these molecules and resulting in sensitive detection. The detection limit of biotin with the proposed method is as low as 48 ng/mL. The most important aspect of this method is the induction of silver aggregation by a protein (avidin), which makes the silver more biocompatible. This technique is very useful for the detection of protein-small molecule complexes.

Optimization of Wave Forms for Pulsed Amperometric Detection of Cyanide and Sulfide with Silver-Working Electrode

  • Park, Seong U;Hong, Seong Uk;Yu, Jae Hun
    • Bulletin of the Korean Chemical Society
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    • v.17 no.2
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    • pp.143-146
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    • 1996
  • A continuous potential pulse is applied to a silver-working electrode on a pulsed amperometric detector (PAD) for detection of free cyanide and sulfide. The moving phase is 0.1 M sodium hydroxide, 0.5 M sodium acetate and 5% (v/v) ethylenediamine mixture, and the flow rate is 0.7 mL/min. Optimized pulse conditions include a -200 mV (vs. Ag/AgCl reference electrode) detection potential(Ed) for 60 msec and 50 mV cleaning potential (Ec) for 120 msec. The silver working electrode surface is not poisoned by cyanide or sulfide, and the PAD maintains long-term stability without loss of sensitivity and reproducibility at these pulse conditions. The detection limit of cyanide and sulfide separated by ion chromatography using an anion exchange column is 0.1 ppm and 0.05 ppm, respectively.

Synthesis of Platinum-Reduced Graphene Oxide (Pt-rGO) Nanocomposite for Selective Detection of Hydrogen Peroxide as a Peroxidase-Mimic Catalyst

  • Doyun Park;Min Young Cho;Kuan Soo Shin
    • Journal of the Korean Chemical Society
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    • v.67 no.6
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    • pp.415-419
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    • 2023
  • In this study, we report the one-pot synthesis of reduced graphene oxide (rGO) containing platinum nanoparticles with catalytic activity to break down hydrogen peroxide as a peroxidase-mimicking catalyst. A single reducing agent was used to reduce graphene oxide and a platinum precursor at a moderately low temperature of 70℃. The rGO was homogeneously decorated with platinum nanoparticles. The catalytic activity of Pt-rGO was investigated for the oxidation of 3,3',5,5'- tetramethylbenzidine (TMB), a peroxidase substrate, in the presence of hydrogen peroxide. The Pt-rGO coupled with glucose oxidase was also able to detect glucose at millimolar concentrations (up to 1 mM). Our results show that the Pt-rGO composite is a promising catalyst for the detection of hydrogen peroxide. This method was also applied for the detection of glucose.

Deep UV Raman Spectroscopic Study for the Standoff Detection of Chemical Warfare Agents from the Agent-Contaminated Ground Surface (지표면 화학작용제 비접촉 탐지를 위한 단자외선 라만분광법 연구)

  • Choi, Sun-Kyung;Jeong, Young-Su;Lee, Jae Hwan;Ha, Yeon-Chul
    • Journal of the Korea Institute of Military Science and Technology
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    • v.18 no.5
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    • pp.612-620
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    • 2015
  • Short-range detection of chemical agents deposited on ground surface using a standoff Raman system employing a pulsed laser at 248 nm is described. Mounted in a vehicle such as an NBC reconnaissance vehicle, the system is protected against toxic chemicals. As most chemicals including chemical warfare agents have unique Raman spectra, the spectra can be used for detecting toxic chemicals contaminated on the ground. This article describes the design of the Raman spectroscopic system and its performance on several chemicals contaminated on asphalt, concrete, sand, etc.

Advances in Rapid Detection Methods for Foodborne Pathogens

  • Zhao, Xihong;Lin, Chii-Wann;Wang, Jun;Oh, Deog Hwan
    • Journal of Microbiology and Biotechnology
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    • v.24 no.3
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    • pp.297-312
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    • 2014
  • Food safety is increasingly becoming an important public health issue, as foodborne diseases present a widespread and growing public health problem in both developed and developing countries. The rapid and precise monitoring and detection of foodborne pathogens are some of the most effective ways to control and prevent human foodborne infections. Traditional microbiological detection and identification methods for foodborne pathogens are well known to be time consuming and laborious as they are increasingly being perceived as insufficient to meet the demands of rapid food testing. Recently, various kinds of rapid detection, identification, and monitoring methods have been developed for foodborne pathogens, including nucleic-acid-based methods, immunological methods, and biosensor-based methods, etc. This article reviews the principles, characteristics, and applications of recent rapid detection methods for foodborne pathogens.

Optimal Sensor Placement of Boundaries and Robustness Analysis for Chemical Release Detection and Response of Near Plant (주변 사업장의 화학물질 확산 감지와 대응을 위한 경계면의 센서배치 최적화 및 강건성 분석)

  • Cho, Jaehoon;Kim, Hyunseung;Kim, Tae-Ok;Shin, Dongil
    • Journal of the Korean Institute of Gas
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    • v.20 no.5
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    • pp.104-111
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    • 2016
  • Recently, the quantities of chemical material are increasing in chemical industries. At that time, release accident is increasing due to aging of equipment, mechanical failure, human error, etc. and industrial complexes found community properties in a specific area. For that matter, chemical release accident can lead to hight probability of large disaster. There is a need to analyze the boundaries optimal sensor placement calculated by selecting release scenarios through release condition and wether condition in a chemical process for release detection and response. This paper is to investigate chlorine release accident scenarios using COMSOL. Through accident scenarios, a numerical calculation is studied to determine optimized sensor placement with weight of detection probability, detection time and concentration. In addition, validity of sensor placement is improved by robustness analysis about unpredicted accident scenarios. Therefore, this verifies our studies can be effectively applicable on any process. As mention above, the result of this study can help to place mobile sensor, to track gas release based concentration data.

General Survey of Detection Methods for Irradiated Foods

  • Yang, Jae-Seung
    • Nuclear Engineering and Technology
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    • v.29 no.6
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    • pp.500-507
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    • 1997
  • The development of detection techniques is needed, in order for regulating authorities to determine whether or not a particular food sample has been irradiated, and label it accordingly so that a consumer's free choice can be exercised. The chemical and physical changes brought about in foods by practical doses of irradiation are very small, and therefore very sensitive methods are required. A number of promising approaches have been developed and evaluated. These include chemical, physical and biological methods ranging from the very simple to highly sophisticated techniques.

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