• Proceedings of the PSK Conference
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• 2003.04a
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• pp.280.1-280.1
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• 2003

The high-performance liquid chromatography method was performed for test method development of related compounds in pharmaceuticals. Using reverse-phase column and gradient elution of 1 ％ acetonitrile-acetonitrile: H20:triethylamine (70:30:0.5), lansoprazole, 2-hydroxybenzimidazole, 2-mercaptobenzimidazole, lansoprazole sulfone, lansoprazole sulfide could be individually identified and quantitated. (omitted)

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.208-210
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• 2002

Baker's yeast was cultured with $Na_2SeO_3$. Selenium compounds in yeast were extracted and analyzed by size exclusion chromatography. Selenium was broadly distributed in the fraction of protein. For the inhibition test of MMP-l induction, selenium containing compounds was fractioned by ultrafiltration

• Korean Journal of Veterinary Service
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• v.27 no.1
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• pp.17-29
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• 2004

A multiresidual analysis was performed to determine 12 sulfonamides(sulfacetamide, sulfadiazine, sulfisomidine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethazine, sulfamonomethoxine, sulfisoxazole, sulfamethoxazole, sulfaquinoxaline, and sulfadimethoxine) in beef and pork simultaneously. The multiresidual analysis for the sulfonamides currently used was able to analyze 5 kinds of sulfonamides at the same time. The method of this 12 sulfonamides multiresidual analysis in this study was matrix solid-phase dispersion(MSPD) by high performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC/MS). The recovery rate of the materials was measured by MSPD method with 3 different extraction solvents; Dichloromethane, DCM: Ethylacetate(3:1), DCM:EA(9:1). Also, samples (84 beef and 205 pork samples) which were positive by EEC-4 plate test from 2001 to 2003 were tested to investigate the kinds of sulfonamides using HPLC. The results from the study were as follows; 1. The recovery rate of the materials was measured by MSPD method with 3 different extraction solvents; Dichloromethane, DCM:Ethylacetate(3:1), DCM:EA(9:1). The method of extraction solvent with DCM:ethyl acetate(9:1) was the most excellent(87.7∼99.3%) in separation and reappearance. 2. In the LC/MS analysis. of sulfonamides, signal to noise ratio was showed relatively high in the positive mode and special ion in the quality analysis was determined via [M+H]$\^$+/ and m/z 156. A spectrum of sulfonamides was showed from all 12 sulfonamides. 3. The samples positive by the EEC-4 plate, a screening test method, were categorized by sulfonamides through Charm II and confirmed the kinds of sulfonamides through HPLC. 1) Among 84 beef samples positive by EEC-4 plate, 20 samples were positive by Charm II and identified as 7 sulfamethazine, 9 sulfadimethoxine, 1 sulfamonomethoxine and 3 unknown status. 2) Among 205 pork samples positive by EEC-4 plate, 42 samples were positive by Charm II and identified as 19 sulfamethazine, 1 sulfadimethoxine, 4 sulfamonomethoxine and 5 unknown status.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.172-187
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• 2024

In good laboratory practice (GLP), analytical method validation prior to toxicity testing is important in terms of concentration setting and sample preparation. The testing agency performed validation of the two requested test substances using high-performance liquid chromatography (HPLC), and as a result, the analysis satisfied the criteria for specificity, system suitability, linearity, intra-day reproducibility, homogeneity, stability, concentration analysis, and quality control. The method was established and validated. However, the content of standard substances in the test report of the requesting institution was found to be 1.34 and 1.17 times higher than the results of the testing institution, confirming that deriving results through validation of analysis methods suitable for GLP is important in terms of securing reliability and stability.

• Biomedical Science Letters
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• v.4 no.1
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• pp.35-42
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• 1998

The effects of CRP purified from human ascites fluid on phagocytic activity of the human macrophage were investigated. CRP was purified using affinity chromatography including absorption on p-diazonium phosphocholine or C-polysaccharide coupled sepharose 4B and gel filtration on hydroxylapatite column chromatography. Macrophage was separated ficoll hypaque gradient density and absorption method, and then was confirmed phagocytic uptake test using latex method. CRP was able either to inhibit or to enhance phagocytic activity of human macrophage against bacteria in vitro. The effects of CRP on phagocytic activity of human macrophage were in time and dose-dependent manners. The additional sequence of reaction mixture against bacteria in vitro shows a threshold stimulus on the activation of phagocytic response upon the CRP.

• Microbiology and Biotechnology Letters
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• v.2 no.2
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• pp.111-117
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• 1974

Studies were carried out on the practical use of Naringinase and some chracteristics of Naringin solublizing enzme which might hydrolyae naringin to purunin. Obtained results were as follows. 1. Selected strain for Naringinase producing was identified to be Aspergillus niger S-1 and its naringinase was applied to chinese citron processing to remove the bitter taste. 2. Of the naringinase, naringin solubilizing enzyme was purified on a DEAE-Sephadex A-50 column and crystalized from acetone and ammonium sulfate. 3. Hydrolized naringin which has higher solubility rather than naringin or naringenin were identified by thin layer chromatography. 4. Hydrolyzed naringin and naringin were separatly determinated by ethylacetate extraction and this result was compared with sensory test.

• Journal of Nutrition and Health
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• v.16 no.2
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• pp.107-114
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• 1983

There has been no specific test available for identifying the sesame oil among common edible oils. As the contents of sesamin and the ratio of sterols allowed the estimation for the genuine sesame oil, the author investigated to establish some instrumental methods for verification of genuine sesame oil and its distribution in the market. The sesame oil was saponified and the sesamin and sterols were isolated from the unsaponiable fraction by Florisil column chromatography. The individual components were determined by gas- chromatography and sesamin standard (purified sesamin) was obtained by silicagel column chromatography. The gas- chromatographic condition using Flame Ionization Detector supported on 10% OV-101 with di-(2-ethylhexyl) sebacate as an internal standard was suitable, and quantitation of sesamin and sterols, including campesterol, stigmasterol and ${\beta}-sitosterol$ was carried out. The results of this study showed that contents of sesamin in genuine sesame oil were 0.3-0.5% and the ratio of stigmasterol to compesterol was 0.3-0.6 and ${\beta}-sitosterol$ to campesterol 3.0-3.8. The 50 samples from the markets in Seoul were composed of 70% genuine sesame oil, and others were mixed with palm oil, rape seed oil and soybean oil.

• Journal of the Korean Society of Combustion
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• v.10 no.1
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• pp.20-26
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• 2005

In the present study, catalytic combustion of hydrogen-air premixture in a millimeter scale monolith coated with Pt catalyst was investigated. As the combustor size decreases, the heat loss increases in proportion with the inverse of the scale of combustion chamber and combustion efficiency decreases in a conventional type of combustor. Combustion reaction assisted by catalyst can reduce the heat loss by decreasing the reaction temperature at which catalytic conversion takes place. Another advantage of catalytic combustion is that ignition is not required. Platinum was coated by incipient wetness method on a millimeter scale monolith with cell size of $1{\times}1mm$. Using this monolith as the core of the reaction chamber, temperatures were recorded at various locations along the flow direction. Burnt gas was passed to a gas chromatography system to measure the hydrogen content after the reaction. The measurements were made at various volume flow rate of the fuel-air premixture. The gas chromatography results showed the reaction was complete at all the test conditions and the reacting species penetrated the laminar boundary layer at the honeycomb and made contact with the catalyst coated surface. At all the measuring locations, the record showed monotonous increase of temperature during the measurement duration. And the temperature profile showed that the peak temperature is reached at the point nearest to the gas inlet and decreasing temperature along the flow direction.

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.706-713
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• 1994

Isothermal vapor-Liquid equilibrium data have been measured for binary systems MTBE-methanol, MTBE-n-heptane, and methanol-n-heptane at $45^{\circ}C$ and $65^{\circ}C$ by using head space gas chromato-graphy (H.S.G.C). Among these systems a minimum azeotrope was observed in both of MTBE-methanol system and n-heptane-methanol system. Particularly n-heptane-methanol system has a heterogeneous minimum azotrope since it has an immisible region. These equilibrium data were correlated with the excess Gibbs energy model, and the thermodynamic consistency test was also carried out by using Redlich-Kister equation.

• Bulletin of the Korean Chemical Society
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• v.30 no.1
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• pp.61-66
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• 2009

An analytical method based on solid-phase extraction and gas chromatography / mass spectrometry has been developed for measurement of acaricides (amitraz, bromopropylate, coumaphos, cymiazole, and tetradifon) in honey sample. In the stability test of acaricides in honey, amitraz underwent a rapid degradation into 2,4-dimethylaniline (DMA), 2,4-dimethylphenylformamide (DMPF), and N-(2,4-dimethylphenyl)-N'-methylformamidine (DMPMF), whileas other acaricides were found to be stable even for over three months. Extraction of five acaricides from 5g of honey sample was carried out by liquid-liquid extraction using 20mL of ethylacetate. For purification, Florisil-SPE cartridge with elution of 5mL of n-hexane/ acetone (55:45, v/v) was found to remove interferences effectively. Quantification was performed using gas chromatography / mass spectrometry in the selected ion monitoring mode. Spiking experiments were carried out to determine the recovery, precision, and limits of detection (LODs) of the method. The overall recovery values from honey spiked at 0.02 and 0.20 ${\mu}g/g$ levels, respectively, were found to be greater than 75% for all acaricides. The method detection limits for acaricides were ranged from 0.1 to 3 ppb. The developed method in this study was applied for the monitoring of acaricides in honey products collected from urban markets in Korea.