• Title/Summary/Keyword: chemical identification

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Synthesis of N$^6$-Aminoalkyl-5'-adenylic Acid Derivatives

  • Kang, Jung-Bu
    • Bulletin of the Korean Chemical Society
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    • v.1 no.4
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    • pp.126-131
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    • 1980
  • Seventeen new $N^{6}$-aminoalkyl derivatives of 5'-adenylic acid and adenosine 5'-triphosphate (Compound I-XVII) were synthesized from 6-chloropurine ribonucleoside by reaction with appropriate diamines. This paper discusses the procedure of synthesis and the identification of the derivatives by ultraviolet spectra, high voltage electrophoresis, paper chromatography, elemental analyses, and other chemical methods.

Missing Value Estimation and Sensor Fault Identification using Multivariate Statistical Analysis (다변량 통계 분석을 이용한 결측 데이터의 예측과 센서이상 확인)

  • Lee, Changkyu;Lee, In-Beum
    • Korean Chemical Engineering Research
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    • v.45 no.1
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    • pp.87-92
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    • 2007
  • Recently, developments of process monitoring system in order to detect and diagnose process abnormalities has got the spotlight in process systems engineering. Normal data obtained from processes provide available information of process characteristics to be used for modeling, monitoring, and control. Since modern chemical and environmental processes have high dimensionality, strong correlation, severe dynamics and nonlinearity, it is not easy to analyze a process through model-based approach. To overcome limitations of model-based approach, lots of system engineers and academic researchers have focused on statistical approach combined with multivariable analysis such as principal component analysis (PCA), partial least squares (PLS), and so on. Several multivariate analysis methods have been modified to apply it to a chemical process with specific characteristics such as dynamics, nonlinearity, and so on.This paper discusses about missing value estimation and sensor fault identification based on process variable reconstruction using dynamic PCA and canonical variate analysis.

Identification of Nandrolone and its Metabolite 5α-Estran-3β, 17α-Diol in Horse Urine after Chemical Derivatization by Liquid Chromatography Tandem Mass Spectrometry

  • Dubey, Saurabh;Beotra, Alka
    • Mass Spectrometry Letters
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    • v.8 no.4
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    • pp.90-97
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    • 2017
  • Androgenic anabolic steroids (AASs) are synthetic derivatives of testosterone with a common structure containing cyclopentanoperhydrophenanthrene nucleus. Their use enhances the muscle building capacity and is beneficial during performance. The AASs are one of the most abused group of substances in horse doping. Liquid chromatography tandem mass spectrometry ($LC/MS^n$) has been successfully applied to the detection of anabolic steroids in biological samples. However, the saturated hydroxysteroids viz: nandrolone, $5{\alpha}-estrane-3{\beta}$, $17{\alpha}-diol$ exhibit lower detection responses in electrospray ionisation (ESI) because of their poor ionisation efficiency. To overcome this limitation pre-column chemical derivatization has been introduced to enhance their detection responses in $LC-ESI-MS^n$ analysis. The aim of present study was to develop a sensitive method for identification and confirmation of nandrolone and its metabolite in horse urine incorporating pre-column derivatization using picolinic acid. The method consists of extraction of targeted steroid conjugates by solid phase extraction (SPE). The eluted steroid conjugates were hydrolysed by methanolysis and free steroids were recovered with liquid-liquid extraction. The resulting steroids were derivatized to form picolinoyl esters and identification was done using LC-ESI-MS/MS in positive ionization mode. The picolinated steroid adduct enhanced the detection levels in comparison to underivatized steroids.

Rapid Detection of Bacteria from Blood Culture by an Electronic Nose

  • Lykos, Peter;Patel, Pravin H.;Morong, Christopher;Joseph, Asha
    • Journal of Microbiology
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    • v.39 no.3
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    • pp.213-218
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    • 2001
  • The treatment of Patients with bacteraemia and septicemia requires accurate and rapid identification of the pathogen so that the physician can be guided regarding the selection of the proper antimicrobial therapy. The usual procedure is to withdraw an aliquot of the positive blood culture sample for gram staining and subculturing on the media for the growth and subsequent identification, and susceptibility determinations. It was noticed that during the process some microbiologists would sniff the effluent gases that are products of metabolism and in some cases guess the identity of the bacterium. That Prompted us to engage in systematic investigation of two gram positive and two gram negative bacteria using an electronic nose that had been proven successful in distinguishing the aroma of coffee beans from different sources. The investigation was successful in illustrating the efficacy of such a device in this clinical setting to distinguish Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis. A representative set of patterns obtained with this apparatus is displayed as well. A representative set of patterns obtained with this apparatus is displayed as well. No effort was made to determine an optimal set of sensors for some specific set of bacterial metabolism gaseous products.

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Microscopic Identification of the Chinese Patent Medicine 'Geum Ryeo Hwan' (금려환(錦儷丸)의 현미감정 연구)

  • Kim, Jeong-Myo;Park, Jong-Hee
    • Korean Journal of Pharmacognosy
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    • v.37 no.2 s.145
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    • pp.116-119
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    • 2006
  • Geum Ryeo Hwan(錦儷丸) is Chinese patent medicine which has been used for women's diseases and climacteric syndrome in Korea. It consists of 12 kinds of powdered crude drugs. In powdered crude drugs, it is hard to identify each component by chemical analysis or morphological examination. However, the method of identification of powdered crude drugs has not been clearly established. Therefore, it is of interest to establish the microscopic method for identification of powdered crude drugs of Chinese patent medicines. The effectiveness of microscopic method is exemplified by the identification of tissue and contents of crude drugs by comparison with standard drugs. Moreover, this method has advantage as a microscale analysis, since it requires only a small amount of specimens. In this study, it is demonstrated that the microscopic method is very effective for the identification of 12 crude drug ingredients in Geum Ryeo Hwan.

Microscopic Identification of the Chinese Patent Medicine 'Ah Myeong Dan' (아명단(兒明丹)의 현미감정연구)

  • Kim, Jeong-Myo;Park, Jong-Hee
    • Korean Journal of Pharmacognosy
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    • v.36 no.3 s.142
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    • pp.205-208
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    • 2005
  • Ah Myeong Dan (兒明丹) is Chinese patent medicine which is used for congenital fever and congenital boils in Korea. It consists of 11 kinds of powdered crude drugs. In powdered crude drugs, it is hard to identify each component by chemical analysis or morphological examination. However, the method of identification of powdered crude drugs has not been clearly established. Therefore, it is of interest to establish the microscopic method for identification of powdered crude drugs of Chinese patent medicines. The effectiveness of microscopic method is exemplified by the identification of tissue and contents of crude drugs by comparison with standard drugs. In this study, it is demonstrated that the microscopic method is very effective for the identification of 11 crude drug ingredients in Ah Myeong Dan.

Identification Performance of Low-Molecular Compounds by Searching Tandem Mass Spectral Libraries with Simple Peak Matching

  • Milman, Boris L.;Zhurkovich, Inna K.
    • Mass Spectrometry Letters
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    • v.9 no.3
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    • pp.73-76
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    • 2018
  • The number of matched peaks (NMP) is estimated as the spectral similarity measure in tandem mass spectral library searches of small molecules. In the high resolution mode, NMP provides the same reliable identification as in the case of a common dot-product function. Corresponding true positive rates are ($94{\pm}3$) % and ($96{\pm}3$) %, respectively.

Modeling of Grade Change Operations in Paper Mills

  • Ko, Jun-Seok;Yeo, Yeong-Koo;Ha, Seong-Mun;Lim, Jung-Woo;Ko, Du-Seok;Hong Kang
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.35 no.5
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    • pp.46-52
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    • 2003
  • In this work we developed the closed-loop model of a paper machine during grade change with the intention to provide a reliable dynamic model to be used in the model-based grade change control scheme. During the grade change, chemical and physical characteristics of paper process change with time. It is very difficult to represent these characteristics on-line by using physical process models. In this work, the wet circulation part and the drying section were considered as a single process and closed-loop identification technique was used to develop the grade change model. Comparison of the results of numerical simulations with mill operation data demonstrates the effectiveness of the model identified.

Separation and Identification of Polycyclic Aromatic Compounds in Pyrolysis Products of Cellulose and Lignin (셀룰로오스와 리그닌의 열분해 생성물중의 여러고리 방향족화합물의 분리와 동정)

  • Park, Nae-Joung;Lee, Milton L.
    • Journal of the Korean Chemical Society
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    • v.28 no.4
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    • pp.244-250
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    • 1984
  • Separation and identification of the polycyclic aromatic compounds (PAC) from pyrolysis products of cellulose and lignin were performed using a combination of acid-base solvent partitioning and silicic acid column chromatography with fused-silica capillary column gas chromatography/ mass spectrometry. Sixteen PAC were positively identifited by retention indices and mass spectra data. Both materials produced the same kinds of PAC. But lignin produced much more PAC than cellulose. Almost no highly carcinogenic heterocyclic PAC containing nitrogen and sulfur were produced.

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