• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.21-26
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• 2005

Gas Chromatography (GC) is a wisely technique used for the separation and analysis of liquid and gas sample. Separation of the sample vapors is achieved via their differential migration through a capillary column with an insert carrier gas. The identity and quantity of each vapor in the mixer can be determined from its retention time in the column and a particular property of the gas, such as thermal conductivity, which can be related to the concentration of sample vapor in the carrier gas. Therefore, the flow characteristics in the spiral gas chromatographic column are numerically investigated in this study. Especially, different pressure drop between the front and the rear of GC column with various flow rates is estimated the governing equations are derived from making using of three-dimensional Naver-Stokes equation with incompressible and laminar model due to the nature of low Reynolds number flow. Using a commercial code, FLUENT, the pressure and flow fields in GC column are calculated with various flow rates. The characteristics of thermal cycling which is one of the most important factors affecting the column efficiency and analysis time is also estimated. Furthermore, numerical analyses are also carried out by using commercial code, ANSYS, with various values of power, which is applied to the heating element located at lower GC column.

• CELLMED
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• v.4 no.2
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• pp.11.1-11.6
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• 2014

Cinnamomum zeylanicum (C. zeylanicum) is a tropical evergreen tree of Lauraceae family. It is one of the oldest culinary spices known and used traditionally in many cultures for centuries. In addition to its culinary uses, cinnamon also possesses as a folk remedy of many health disease condition including analgesic, antiseptic, antispasmodic, aphrodisiac, astringent, carminative, haemostatic, insecticidal, and parasiticide and memory enhancing property. This study was aimed to assess the acetylcholinesterase and butyrylcholinesterase inhibitory activity of standardized methanol extract of the C. zeylanicum. Gas chromatography - mass spectrometry (GC-MS) and high performance liquid chromatography (HPLC) analysis were done to identify the presence of eugenol as chemical component and support the neuroprotective activity in the extract. Anticholinesterase inhibitory activity of crude methanol extract of C. zeylanicum leaves and cinnamon oil were evaluated by 96-well microtiter plate assay and thin layer chromatography bioassay detection methods. This study revealed that cinnamon oil ($IC_{50}:45.88{\pm}1.94{\mu}g/ml$) has better anticholinesterase activity than methanol extract ($IC_{50}:77.78{\pm}0.03{\mu}g/ml$). In HPLC analysis, retention time of eugenol in cinnamon oil was found to be 15.81 min which was comparable with the retention time (15.99 min) of the reference standard, eugenol. Seven chemical compounds were identified by GC-MS analysis, in which eugenol as an important phytoconstituents. Thus the phytochemicals from C. zeylanicum methanol leaves extract could be developed as potential source of anticholinesterase activity, with particular benefit in the symptomatic treatment of Alzheimer's disease.

• Journal of Environmental Science International
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• v.7 no.6
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• pp.811-815
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• 1998

Currently in Korea, standard operating procedure for the analyses of phenolic compounds in water is the spectrometric comparison of colors developed by 4-amino antipyrin with phenolic compounds. It is however that this method cannot identify individual compound and that some phenolic compounds do not react with 4-amino antipyrin. Spectrometric determinations of phenolic compounds were compared with chromatographic analyses of gas chromatography (GC) and high pressure liquid chromatography (HPLC) of various phenolic compounds. Individual phenolic compounds could be determined by both chromatographic methods but HPLC methods were more precise with lower detection levels in general.

• Journal of the Korea Society of Computer and Information
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• v.21 no.5
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• pp.167-175
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• 2016

The volatile component analysis of 82 commercialized liquors(44 samples of single malt whisky, 20 samples of blended whisky and 18 samples of brandy) was carried out by gas chromatography after liquid-liquid extraction with dichloromethane. Pattern recognition techniques such as principle component analysis(PCA), cluster analysis(CA), linear discriminant analysis(LDA) and partial least square discriminant analysis(PLSDA) were applied for the discrimination of different liquor categories. Classification rules were validated by considering sensitivity and specificity of each class. Both techniques, LDA and PLSDA, gave 100% sensitivity and specificity for all of the categories. These results suggested that the common characteristics and identities as typification of whiskies and brandys was founded by using multivariate data analysis method.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.145-149
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• 2003

This study was to compare the fatty acid composition of mare milk with cow milk in liquid, powder, cream and oil by gas-liquid chromatography. This study was to compare the fatty acid composition of mare milk with cow milk in liquid, powder, cream and oil by gas-liquid chromatography. These results showed that overall fatty acid concentration of mare milk was much higher than that of cow milk especially linoleic acid(C18:2) and linolenic acid(C18:3). The concentrations of oleic acid, linoleic acid and linolenic acid of mare milk were higher than those of cow milk in liquid, powder, cream and oil.

• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.257-260
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• 2008

• Analytical Science and Technology
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• v.13 no.3
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• pp.385-393
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• 2000

A gas chromatography-mass spectrometric (GC/MS) procedure for the determination of amineptine (dihydro-10, 11-dibenzo[a, d] cycloheptenyl-5-amino-7-heptanoic acid) and its main metabolites in human urine was described. Amineptine has been known to be extensively metabolized by the ${\beta}$-oxidation of the heptanoic side chain with formation of pentanoic side chain metabolite ($C_5$-metabolite), and lactamizarion by internal dehydration of (${\beta}$-oxidized metabolite (${\delta}$-lactam). The detection of these compounds was based on acid hydrolysis, liquid-liquid extraction and trimethylsilylated derivatization of the carboxylic acid group. For the determination of amineptine and its metabolites in biological fluids, selected ions at the m/ 192, molecular ion and one of the characteristic ions were monitored by GC/MS. On the excretion study of amineptine in human urine, 70-90% of amineptine, ${\delta}$-lactam, and $C_5$-metabolite were found to be excreted within 4 hours and their excretion completed within 20 hours.

• Journal of Pharmaceutical Investigation
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• v.35 no.5
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• pp.383-388
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• 2005

A simple and specific method for determination of methyltestosterone (MT) has been established by a gas chromatography/mass selective detector and applied in plasma of healthy male volunteers received a single oral dose of 50 mg MT $(Testo^{TM}\;tablets,\;25\;mg)$ for bioavailability test. This method involves using liquid-liquid extraction of the sample with diethyl ether and derivatization with MSTFA. MT showed good resolution in this condition. The detection limit of quantitation was 5 ng/ml. A good linearity (r>0.996) was obtained at the range of 5-250 ng/ml of MT. Intra-day precision and accuracy were 2.76-12.56% and 0.39-8.01 %, and inter-day precision and accuracy were 2.29-17.69% and 0.42-7.99%, respectively. The established method was applied on bioavailability test of MT in human volunteers. The value of $AUC_{0\;to\;last}$ to last was $264.5{\pm}123.9\;ng{\cdot}hr/ml$ and that of $AUC_{0\;to\;inf}$ was determined to be $275.2{\pm}126.5\;ng{\cdot}hr/ml$. The values of $C_{max}$ and $T_{max}$ were $95.9{\pm}67.1\;ng/ml$ and $1.13{\pm}0.9\;hr$, respectively. The mean elimination half-life $(t_{1/2})$ was $4.4{\pm}0.9\;hr$. This analytical method is suitable and useful for the pharmacokinetics and bioequivalence studies of MT.

• Journal of Ginseng Research
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• v.45 no.1
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• pp.1-21
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• 2021

Panax species have gained numerous attentions because of their various biological effects on cardiovascular, kidney, reproductive diseases known for a long time. Recently, advanced analytical methods including thin layer chromatography, high-performance thin layer chromatography, gas chromatography, high-performance liquid chromatography, ultra-high performance liquid chromatography with tandem ultraviolet, diode array detector, evaporative light scattering detector, and mass detector, two-dimensional high-performance liquid chromatography, high speed counter-current chromatography, high speed centrifugal partition chromatography, micellar electrokinetic chromatography, high-performance anion-exchange chromatography, ambient ionization mass spectrometry, molecularly imprinted polymer, enzyme immunoassay, 1H-NMR, and infrared spectroscopy have been used to identify and evaluate chemical constituents in Panax species. Moreover, Soxhlet extraction, heat reflux extraction, ultrasonic extraction, solid phase extraction, microwave-assisted extraction, pressurized liquid extraction, enzyme-assisted extraction, acceleration solvent extraction, matrix solid phase dispersion extraction, and pulsed electric field are discussed. In this review, a total of 219 articles published from 1980 to 2018 are investigated. Panax species including P. notoginseng, P. quinquefolius, sand P. ginseng in the raw and processed forms from different parts, geographical origins, and growing times are studied. Furthermore, the potential biomarkers are screened through the previous articles. It is expected that the review can provide a fundamental for further studies.

• The Journal of Korean Obstetrics and Gynecology
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• v.33 no.2
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• pp.1-12
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• 2020

Objectives: This study was conducted to find out the optimal extraction time for Artemisia argyi. Methods: The compositional pattern was compared with HPLC (High Performance Liquid Chromatography) and GC (Gas-Chromatography) by decocting Artemisia argyi 10, 60, 120 minutes respectively. Results: With longer extraction time, the contents of reference compounds were extracted 1.1 times more when 3,4-dicaffeoylquinic acid was extracted for 60 minutes than when extracted for 10 minutes in HPLC test, but the contents were reduced when extracted for 120 minutes compared to 60 minutes extraction time. 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, 4,5-di-O-caffeoylquinic acid, jaceosidin, and eupatilin showed the largest yield rate when extracted for 10 minutes, and it decreased as time passed. The contents of chlorogenic acid, 3,5-dicaffeoylquinic acid, 4,5-dicaffeoylquinic acid, jaceosidin, scoparone, and eupatilin were detected only in 10 minutes extraction but not in 60 or 120 minutes extraction according to GC test. Conclusions: The results show that extraction time could affect the physicochemical characteristic or composition of Artemisia argy extracted. Thus, short extraction time could be useful for decoction of Artemisia argyi.