• YAKHAK HOEJI
• /
• v.38 no.2
• /
• pp.179-183
• /
• 1994

Callus was derived from the shoots of Cnidium officinale. The growth rate of callus and the production of essential oils were studied under different culture conditions. The essential oils in the rhizome of Cnidium officinale and the cultivated callus were analyzed and compared by gas chromatography and mass spectrometry. It appeared that NAA induced higher growth rate and production of essential oils than 2,4-D. The compositions of essential oils were influenced by the illumination. Butyl phthalide, cnidilide, senkyunolide, butylidene phthalide, ligustilide, grandisol, tricosane, 3-methylphenol and 2-pentylthiophene were identified in the cultivated callus.

• Fibers and Polymers
• /
• v.5 no.2
• /
• pp.83-88
• /
• 2004

In order to assess the potential of the hydroxy-containing polyamic acid (PHAA) synthesized from 3,3'-dihydroxy benzidine and pyromellitic dianhydride for a fire-safe polymer, the cyclization pathway of PHAA has been investigated using a model compound prepared from 2-aminophenol and phthalic anhydride. The reaction was monitored. by $^1{H-nuclear}$ magnetic resonance. N-(2-hydroxyphenyl) phthalamic acid is converted to N-(2-hydroxyphenyl) phthalimide at ca. 175$^{\circ}C$, showing endothermic reaction. The imide structure is rearranged to the benzoxazole structure over ca. $400^{\circ}C$. These results are similar with that of PHAA. According to pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) data, water and carbon dioxide are released during the cyclization and rearrangement reaction. One DMAc molecule is complexed with one carboxyl acid group in PHAA, which accelerates the imidization process to release more easily the flame retardant, water.

• Preventive Nutrition and Food Science
• /
• v.17 no.3
• /
• pp.234-238
• /
• 2012

The volatile aroma constituents of Chrysanthemum zawadskii var. latilobum K. were separated by hydro distillation extraction (HDE) method using a Clevenger-type apparatus, and analyzed by gas chromatography-mass spectrometry (GC/MS). The yield of C. zawadskii var. latilobum K. flower essential oil (FEO) was 0.12% (w/w) and the color was light green. Fifty-five volatile chemical components, which make up 88.38% of the total aroma composition, were tentatively characterized. C. zawadskii var. latilobum K. FEOs contained 27 hydrocarbons, 12 alcohols, 7 ketones, 4 esters, 1 aldehyde, 1 amine, and 3 miscellaneous components. The major functional groups were terpene alcohol and ketone. Borneol (12.96), (${\pm}$)-7-epi-amiteol (12.60), and camphor (10.54%) were the predominant volatiles. These compounds can be used in food and pharmaceutical industries due to their active bio-functional properties.

• Elastomers and Composites
• /
• v.51 no.3
• /
• pp.233-239
• /
• 2016

Polyethylene (PE) and maleic anhydride-grafted PE (PE-g-MAH) were pyrolyzed, and their pyrolysis products were analyzed using gas chromatography/mass spectrometry (GC/MS) to investigate the influence of MAH grafted onto PE on pyrolysis behaviors. Major pyrolysis products of PE and PE-g-MAH were n-alkanes, 1-alkenes, ${\alpha},{\omega}$-alkadienes, and aromatic compounds. 1-Alkenes were more formed than n-alkanes, ${\alpha},{\omega}$-alkadienes, and aromatic compounds. Butadiene was more produced from PE than PE-g-MAH, whereas toluene and ethyl benzene were more generated from PE-g-MAH than PE. Difference in the pyrolysis behaviors between PE and PE-g-MAH were explained by initial decomposition of MAH moiety.

• Korean journal of food and cookery science
• /
• v.13 no.5
• /
• pp.674-680
• /
• 1997

Volatile flavor components of fresh, shady air dried, and presteamed shady air dried Chamnamul (Pimpinella brachycarpa) were collected by simultaneous steam distillation-extraction method, and essential oils were analyzed by gas chromatography-mass spectrometry (GC/MS). Twenty five, 17 and 23 volatile flavor components were identified in essential oils extracted from the fresh, shady air dried, and presteamed shady air dried Chamnamul samples, respectively; however, the kinds of individual components and its percent content of the total volatiles were varied depending on samples. The principal components of Chamnamul were isobutanal, trans caryophyllene, trans ${\beta}$-farnesene, and ${\alpha}$-selinene. Terpenoid compounds reached 44.11%, 33.91% and 72.63% respectively in fresh, shady air dried, and presteamed shady air dried Chamnamul.

• Analytical Science and Technology
• /
• v.9 no.4
• /
• pp.331-335
• /
• 1996

Flavor constituents of green tea flower produced in Korea were analyzed by gas chromatography and mass spectrometry. 56 compounds in sample were separated and indentified as 22 hydrocarbons, 14 alcohols, 6 aldehydes, 5 esters, and 9 others. Higher concentrated substances were heneicosyl formate, ${\alpha}$-phenyl ethyl alcohol, and acetophenone. Germacrene D as a sesquiterpene were also identified.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.04a
• /
• pp.195-198
• /
• 2005

A solid-phase microextraction and gas chromatography-mass spectrometry for the extraction and analysis of methyl-tert-butyl ether has been described. methyl-tert-butyl ether was extracted from aqueous solution using SPME fiber coated polydimethylsiloxane and analysed by GC-MS with capillary column. Extraction parameters and chromatographic separation conditions were optimized. The applied method represented good analytical performance in terms of precision (3-8%, RSD) and accuracy(93-102%, mean recovery) with a method detection limit of 0.03 ppb.

• Food Science and Biotechnology
• /
• v.18 no.6
• /
• pp.1495-1499
• /
• 2009

The volatiles formed from the reactions of L-ascorbic acid with L-alanine at 5 different pH (5, 6, 7, 8, or 9) and $140{\pm}2^{\circ}C$ for 2 hr was performed using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis were identified to be 25 different kinds. The reaction between L-ascorbic acid and L-alanine led mainly to the formation of pyrazines. Many of these were alkylpyrazines, such as 3-ethyl-2,5-dimethylpyrazine, 2,5-dimethylpyrazine, 2-ethyl-5-methylpyrazine, 3,5-diethyl-2-methylpyrazine, methylpyrazine, 2-ethyl-6-methylpyrazine, and 2,3-diethyl-5-methylpyrazine, other compounds identified were furans, phenols, benzoquinones, 2,4,6-trimethylpyridine, and 2-methylbenzoxazole. The studies showed that furans, such as furfural and benzofuran were formed mainly at acidic pH. In contrast, higher pH values could promote the production of pyrazines.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.24 no.3
• /
• pp.454-458
• /
• 1995

Alkylpyrazines in snow crab cooker effluent(SCCE) and effluent concentrate(EC) were quantitatively analyzed and compared by simultaneous steam distillation-solvent extraction/gas chromatography/mass spectrometry(SDE/GC/MS). A total of 11 pyrazines were identified in both SCCE and EC. Amounts of tetramethylpyrazine, 2,5-dimethylpyrazine, trimethylpyrazine, and 2,6-dimethylpyrazine were 23.0, 21.1, 13.8, and 13.3 times higher, respectively, in EC than those in SCCE. The total amount of pyrzines in EC (1664.0${\pm}$171.1ng/g) was 8.1 times higher than that in SCCE(204.5${\pm}$32.2). The compounds, ethylpyrazine and 2-ethyl-3,6-dimethylpyrazine, were only detected in EC.

• YAKHAK HOEJI
• /
• v.54 no.2
• /
• pp.122-125
• /
• 2010

The essential oil fraction was extracted from the aerial parts of the plant by steam distillation method and its composition was analyzed by GC-MS (gas chromatography-mass spectrometry) which led to the identification of 43 compounds. Dehydroelsholtzia ketone (56.81%) and elsholtzia ketone (30.05%) were identified as the predominant components of this oil. The antibacterial activities of the essential oil fraction were assessed by micro-dilution tests against antibioticsusceptible and -resistant strains of Streptococcus pneumoniae, Staphylococcus aureus, Salmonella enteritidis, and S. typhimurium. The oil inhibited most of the tested strains significantly resulting MICs (minimum inhibiting concentrations) between 2 mg/ml and >16 mg/ml. In most cases of this study Streptococcus pneumoniae and Staphylococcus aureus showed higher sensitivity to this oil than Salmonella strains.