• Korean Journal of Pharmacognosy
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• v.31 no.4
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• pp.416-420
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• 2000

Ursolic acid was isolated from Prunellae Herba (Prunella vulgaris var. lilacina) and identified by direct comparison with an authentic sample. A method of analysis for the evaluation of ursolic acid was developed based on extraction of ground plant material, followed by quantitative determination using capillary gas chromatography of the TMS derivative. Quantitative analysis by GC after derivatisation under mild silylating conditions showed 0.31% ursolic acid in 20 samples collected throughout regions of Korea while no ursolic acid was detected in the samples of the whole plant of Thesium chinense, a substitute for Prunellae Herba in southern regions of Korean peninsula.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.395.2-395.2
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• 2002

The determination method for 11 corticosteroids (betamethasone, cortisol. cortisone, cortisone acetate. dexamethasone. cortisol acetate, isoflupredone acetate, methylprednisolone. prednisone, prednisolone, and triamcinolone acetonide) in a herbal medicinal preparation (Sibjeondaibotang) by a gas chromatography-mass spectrometric (GC-MS) method with selected ion monitoring (SIM) mode is described. Samples (4 mL) were extracted by liquid-liquid extraction with diethyl ether. (omitted)

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.382-384
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• 2013

We evaluated the presence of uniconazole residual pesticide in agricultural products by using multiclass pesticide multiresidue methods. Samples were collected from January to August, 2012. The pesticide was detected in 14 samples among the 3,632 samples tested. Amount of the uniconazole pesticide ranged from 0.098 to 2.2 mg/kg in the 14 samples. This method was described for the simultaneous determination of uniconazole by using gas chromatography with an electron capture detector (GC-ECD) and mass spectrometry (MS). For evaluating the GC-ECD method, uniconazole was spiked into gyeojachae at a level of 0.05, 0.5 mg/kg. The recoveries of uniconazole with the GC-ECD method ranged from 98.9-109.4%. The results indicate that our method of simultaneous analysis is applicable to uniconazole analysis.

• Analytical Science and Technology
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• v.14 no.3
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• pp.274-285
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• 2001

In this study, the thermal desorption-cryofocusing-gas chromatographic(TD-C-GC) method was developed for determination of volatile organic compounds(VOCs) in ambient air and was applied at the municipal solid waste landfill sites. On-column cryofocusing was possible only with a 100 ml dewars bottle in TD-C-GC method with a stainless steel column. However, high operating pressure was needed for purging VOCs from the absorbent trap, which was able to solve by pressure programming with a electric pressure controller. By using both pressure and temperature programming brought increasing of resolution power in on-column cryofocusing method, but the high pressure caused a leakage of sample tube with repeated use. A loop cryofocusing devise was also developed and compared with the direct on-column method. In loop cryofocusing method, VOCs were concentrated on a 0.8mm i.d. loop which is located between the injector and separation column by using liquid nitrogen. In order to purge VOCs from the absorbent trap, only 0.4 psi of pressure was need in the loop cryofocusing method. Dual detection system was applied for the analysis of VOCs; a FID was used for hydrocarbons and a FPD was used for sulfur-containing compounds. Qualitative analysis was done by on-column cryofocusing GC-MS system. Among the large number of VOCs, toluene was the most abundant. Hydrogen sulfide, dimethyl sulfide, carbon disulfide, dimethyl disulfide and methyl propyl disulfide were detected at landfill site by FPD.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1260-1268
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• 2018

To improve fuel performance and specific characteristics of long storage and moving through fuel systems additives should be added in kerosene type aviation turbine fuel (AVTUR) such as antioxidant, fuel system icing inhibitor (FSII), electric conductivity improvers and so on. The dosage of additives has to be analyzed qualitatively and quantitatively due to inspect the quality of abnormal fuel and distinguish other petroleum products. Multi-dimensional GC-MS (MDGC-MS) with Deans switching technique are applied the determination of antioxidant and FSII, which are added with AVTUR containing complex mixture of hydrocarbons. Antioxidant and FSII in the range of 2.5-20 mg/L was quantitatively and qualitatively analyzed using MDGC-MS and the detection limit was about twice as low as that of the 1-dimensional GC-MS results. The method in this study has been higher peak resolution compared with GC-MS and could be simultaneously analyzed different two additives without sample pre-treatment.

• Journal of the Korean Society of Tobacco Science
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• v.27 no.1 s.53
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• pp.100-106
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• 2005

To obtain the optimum condition for analysis of 10 alkaloids in tobacco leaves, such as nicotine, nornicotine, anatabine, anabasine, myosmine, cotinine, 2,3'-dipyridyl, $\beta-nicotyrine,\;\beta-nornicotyrine\;and\;\beta-formylnornicotin$, 5 types of extraction method were investigated by GC-FID and GC/MS. The optimum condition of alkaloid extraction was achieved by using methanol:dichloromethane(1:3, v/v) after NaOH treatment. The use of mass selective detector (MSD) provided unambiguous nicotine related alkaloid analysis. Alkaloids in various tobacco leaves were extracted with the optimum extraction condition and quantified by GC/MS/SIM mode. Compared with concentrations of alkaloids among the various tobacco leaves, the concentration of alkaloids was generally in the order burley > flue-cured > oriental tobacco. In flue-cured tobacco leaves, the order of concentration of alkaloids was nicotine > anatabine > nornicotine > $\beta-nicotyrine\;>\;\beta-formylnornicotine\; >\;myosmine\;>\;2,3'-dipyridyl\;>\;cotinine\;>\;anabasine\;>\;\beta-nornicotyrine$. However, in the case of burley and oriental tobacco leaves, the concentration of nornicotine was higher than that of anatabine.

• Analytical Science and Technology
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• v.6 no.3
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• pp.335-343
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• 1993

The structure of cerebrosides from soybean embryo was determined using fast atom bombardment mass spectrometer (FAB-MS), gas chromatography mass spectrometer (GC-MS) and TLC. The components of cerebroside were determined by GC-MS after acid hydrolysis. The molecular weight distribution of cerebroside was measured by positive mode FAB-MS with LiOH saturated 3-nitrobenzylalcohol(3-NBA) matrix. Structures of individual components of complex mixtures can be determined easily by this process. The major constituent of soybean extracted cerebroside was determined as the glucoside of N-2'-hydroxypalmitoyl-sphingadienine.

• Journal of the Korean Chemical Society
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• v.41 no.2
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• pp.105-112
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• 1997

The smelly nitro compounds were extracted from dried fishes by simultanous distillation and extraction, then were analyzed by GC-MS. Carbon number and order of an amine could be predicted by using retention time and equivalent chain length. Anchovy, codfish, imitation crab meat, cuttle fish, file fish, pollack, shrimp, octopus, harvest fish, and hard-shelled mussel were used for this investigation. Various smelly nitro compounds such as methylamine, acetamide, thiazole, 2-hydroxy isopropylamine, N-methyl pyrroline, piperidine, cyclohexylamine were identified, however, dimethylamine, trimethylamine, diethylamine were not detected. Principal components analysis was applied to GC-MS profiles for pattern recognition of smelly nitro compounds in dried fishes. Multivariate aspects using principal components analysis were very useful for pattern recognition of smelly components, category similarity.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.120.2-121
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• 2003

The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring (GC/MS-SIM) mode followed by two work-up methods for comparison; isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in paper samples were extracted with acetonitrile. (omitted)

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4243-4246
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• 2012