• 제목/요약/키워드: Chemical Determination

검색결과 1,723건 처리시간 0.032초

쌀과 콩 중 규제잔류 농약의 동시분석에 관한 연구 (A Study on the Simultaneous Analysis of Regulated Pesticides Residues from Rice and Soy Bean)

  • 김택제;어윤우;이재성
    • 대한화학회지
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    • 제35권5호
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    • pp.560-568
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    • 1991
  • 국내에서 현재 규제되고 있는 농약에 대해 신속, 간단한 동시분석법이 연구되었다. 시료는 아세톤과 메탄올로 추출하고 물을 가한 다음, $CH_2Cl_2$로 분배시킨다. 추출물은 Bio-Beads S-X3 컬럼에서 cyclohexane-methylene chloride의 용출액 11ml를 받아 불순물을 분리, 제거하고 ECD/NPD가 병렬되게 BP-1(methyl silicone) 모세관 컬럼에 연결된 기체 크로마토그래피로 분석한다. 농약 첨가에 의한 평균 회수율은 쌀에서 83% 이상이었고, 콩에서 3종 농약을 제외하면 81% 이상이었다. 검출한계는 쌀에서 0.002 ppm(${\alpha}$-BHC 등)~0.3 ppm(carbaryl 등) 이었다.

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Investigating chemical features of Panax notoginseng based on integrating HPLC fingerprinting and determination of multiconstituents by single reference standard

  • Yang, Zhenzhong;Zhu, Jieqiang;Zhang, Han;Fan, Xiaohui
    • Journal of Ginseng Research
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    • 제42권3호
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    • pp.334-342
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    • 2018
  • Background: Panax notoginseng is a highly valued medicine and functional food, whose quality is considered to be influenced by the size, botanical parts, and growth environments. Methods: In this study, a HPLC method integrating fingerprinting and determination of multiconstituents by single reference standard was established and adopted to investigate the chemical profiles and active constituent contents of 215 notoginseng samples with different sizes, from different botanical parts and geographical regions. Results: Chemical differences among main root, branch root, and rotten root were not distinct, while rhizome and fibrous root could be discriminated from other parts. The notoginseng samples from Wenshan Autonomous Prefecture and cities nearby were similar, whereas samples from cities far away were not. The contents of major active constituents in main root did not correlate with the market price. Conclusion: This study provided comprehensive chemical evidence for the rational usage of different parts, sizes, and growth regions of notoginseng in practice.

Colorimetric Determination of pH Values using Silver Nanoparticles Conjugated with Cytochrome c

  • Park, Jun-Su;Choi, In-Hee;Kim, Young-Hun;Yi, Jong-Heop
    • Bulletin of the Korean Chemical Society
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    • 제32권9호
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    • pp.3433-3436
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    • 2011
  • Some of metal nanoparticles have the potential for use as colorimetric assays for estimating solution properties, such as pH and temperature due to localized surface plasmon (LSP) phenomena. This report describes the use of silver nanoparticles (AgNP) conjugated with cytochrome c (Cyt c) for the colorimetric determination of solution pHs. When the pH of a solution decreases, the Cyt c immobilized on the AgNP undergoes a conformational change, leading to a decrease in the interparticle distance between Cyt c-AgNP probes and consequent red-shift in LSP. As a result, the color of the Cyt c-AgNP probe solution changes from yellow to red and finally to a grayish blue in the pH range from 11 to 3. This gradual color change can be used to determine the pH of a solution over a wide pH range, compared to other colorimetric methods that use gold nanoparticles.

네모파 산화전극 벗김 전압전류법을 이용한 게르마늄의 미량분석 (Determination of Trace Level Germanium(IV) by Square Wave Anodic Stripping Voltammetry)

  • 김일광;천현자;정승일;박성우;유재훈
    • 대한화학회지
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    • 제37권11호
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    • pp.943-950
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    • 1993
  • 8.0 ${\times}\;10^{-2}$ M catechol이 들어있는 5.0 ${\times}\;10^{-2}$ M 과염소산 지지전해질 용액속에서 네모파 산하전극벗김 전압전류법으로 게르마늄의 미량분석을 조사하였다. ppb 수준의 분석에서는 석출시간 120초, 석출전위 -0.9 volts, 주파수 100Hz일 때 가장 적합하였다. 구리와 납, 실리콘 같은 금속이온이 상당량 존재하여도 공존이온이 영향을 받지 않고 게르마늄의 분석이 가능하였다. 검량선은 0.40 ppb 에서 2.0 ppm 범위까지 양호한 직선성을 보였으며, 검출한계는 0.080 ppb 이였다. 이 방법은 분석시간이 짧고 감도가 좋기 때문에 미량 게르마늄 분석에 유용하였다

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Determination of Dibutyltin in Sediments Using Isotope Dilution Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry

  • Yim, Yong-Hyeon;Park, Ji-Youn;Han, Myung-Sub;Park, Mi-Kyung;Kim, Byung-Joo;Lim, Young-Ran;Hwang, Eui-Jin;So, Hun-Young
    • Bulletin of the Korean Chemical Society
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    • 제26권3호
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    • pp.440-446
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    • 2005
  • A method is described for the determination of dibutyltin (DBT) in sediment by isotope dilution using liquid chromatography inductively-coupled plasma/mass spectrometry (LC-ICP/MS). To achieve the highest accuracy and precision, special attentions are paid in optimization and evaluation of overall processes of the analysis including extraction of analytes, characterization of the standards used for calibration and LC-ICP/MS conditions. An approach for characterization of natural abundance DBT standard has been developed by combining inductively-coupled plasma/optical emission spectrometry (ICP/OES) and LC-ICP/MS for the total Sn assay and the analysis of Sn species present as impurities, respectively. An excellent LC condition for separation of organotin species was found, which is suitable for simultaneous DBT and tributyltin (TBT) analysis as well as impurity analysis of DBT standards. Microwave extraction condition was also optimized for high efficiency while preventing species transformation. The present method determines the amount contents of DBT in sediments with expanded uncertainty of less than 5% and its result shows high degree of equivalence with reference values of an international inter-comparison and a certified reference material (CRM) within stated uncertainties.