• Analytical Science and Technology
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• v.27 no.2
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• pp.100-107
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• 2014

Plastic has been widely used in modern artworks' materials due to its merits of process ability and mass production. In the country, value of plastic artifact is increasing but the field of plastic study is limited to industrial purpose. In this study, Identification methods of plastic were performed by SPME-GC/MS and pyrolysis-GC/MS using trace of samples. As a result of identification using SPME-GC/MS, aromatic compounds were identified from polyvinyl chloride. And alkane compounds were identified from polyethylene, and polypropylene. Aromatic compounds were identified from polystyrene, and diethylene glycol appeared in polyurethane based on polyester was identified from polyurethane. As a result of identification using pyrolysis- GC/MS, aliphatic alkenes compounds and phthalate(DEHP) were identified from polyvinyl chloride. Aliphatic alkenes compounds and phthalate(DIBP) were detected from polyethylene. 1-hexene, etc., were detected from polypropylene, aromatic compounds were identified from polystyrene, and methylene diphenyl diisocyanate which is polyurethane basic material was confirmed from polyurethane. This study suggested that non-destructive SPME and pyrolysis-GC/MS are useful to identify compounds particularly polystyrene and polyurethane. These two analytical methods were expected to be applied for identification of unidentified plastic artworks before conservation treatment.

• Applied Chemistry for Engineering
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• v.28 no.1
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• pp.23-28
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• 2017

Pyrolysis characteristics of waste plastic films were investigated by using a thermogravimetric analysis and pyrolyzer-gas chromatography/mass spectrometry. Thermogravimetric analysis results revealed that the pyrolysis of waste plastic films can be divided into two distinct reactions; (1) the decomposition reaction of starch at between 200 and $370^{\circ}C$ and (2) that of other plastic polymers such as PS, PP, PE at between 370 and $510^{\circ}C$. The kinetic analysis results obtained by using the revised Ozawa method indicated that the apparent activation energy of the pyrolysis reaction of waste plastic films was also changed dramatically according to the different decomposition reactions of two major waste plastic film components. Py-GC/MS results also revealed that the typical pyrolyzates of each polymer in waste plastic films were levoglucosan (starch), terephthalic acid (PET), styrene monomer, dimer, and trimer (PS), methylated alkenes (PP), and triplet peaks (PE) composed of alkadiene/alkene/alkane. The phthalate, used as a polymer additive, was also detected on the pyrogram of waste plastic films mixture.

• Journal of Soil and Groundwater Environment
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• v.6 no.3
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• pp.73-91
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• 2001

compounds (VOCs) were selected for assessment of VOCs contamination in some urban runoff and groundwater samples in Seoul. They included 3 aromatic hydrocarbons, 13 alkyl benzenes, 1 ether, 26 halogenated alkanes, 10 halogenated alkenes, and 9 halogenated aromatics. The levels of VOCs in urban runoff and groundwater were measured for samples collected in March 2000, June 2000 and November 2000 in Seoul City. A total of 78 samples (44 run-off water, 27 groundwater, and 7 samples from 4 urban wastewater treatment plants in Seoul) were collected and analysed by GC-MS with purge and trap. After examination of the runoff, it was concluded that alkyl benzenes and aromatic hydrocarbons were organic compounds which were significantly impacted by traffic flows in Seoul. Of 62 VOCs, only 11 VOCs were not detected in runoff samples, while 14 VOCs were detected in 27 groundwater samples. The toluene content in the runoff was extremely variable from 0.1ppb to 29,310ppb, depending on the different sampling sites. The concentrations of xylene ranged between 0.07ppb and 2970ppb in the runoff. The concentrations ranged from 0.05ppb to 33.0ppb for benzene, 0.05ppb to 960ppb for ethylbenzene, 0.08ppb to 20ppb for trichloromethane (chloroform) , 0.03ppb to 4.30ppb for trichloroethylene(TCE) and 0.1ppb to 50ppb for 1,1,2-trichloroethane. From the preliminary study of groundwater from some wells in Seoul, the most frequently detected VOCs are djchlorornethane(methylene chloride), trichloromethane(chloroform) and toluene. Most of aromatic hydrocarbons, alkyl benzenes and other solvents generally lower than detection limits.

• Korean Journal of Plant Taxonomy
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• v.50 no.2
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• pp.148-153
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• 2020

Cleisostoma scolopendrifolium is an orchid species solely pollinated by the male bee Megachile yasumatsui. Although C. scolopendrifolium is an endangered species in Korea, little is known about its pollination mechanisms or the profiles of its chemical attractants. This study provides evidence that the Cleisostoma orchid attracts male bees as pollinators by mimicking female mating signals. We found 13 hydrocarbons in the Cleisostoma orchid flower presumed to be involved in sex pheromone mimicry: five alkanes (tricosane, pentacosane, heptacosane, nonacosane, and hentriacontane), compounds of cuticular hydrocarbons which function as chemical cues for the recognition of mates and species in social insects; and eight alkenes ((z)-9-tricosene, (z)-9-pentacosene, (z)-11-pentacosene, (z)-9-heptacosene, (z)-11-heptacosene, (z)-9-nonacosene, (z)-11-nonacosene, and (z)-11-hentriacontene) which serve as sex pheromones in several insects. We suggest that these hydrocarbons play a key role in the pollination mechanism between Cleisostoma orchids and Megachile bees.

• Microbiology and Biotechnology Letters
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• v.27 no.3
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• pp.236-245
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• 1999

Andong Soju is a Korean traditional distilled liquor brewed with Nuruk which is cultured with wild microorganisms. To provide useful information for scientific production and systematic quality control of traditional distilled liquor, the effects of mixed culture of the alcoholic yeasts and saccharifying molds isolated from the Nuruk, and mashes on the flavor and sensory characteristics were investigated. Distillate from mashes cocultured with Saccharomyces cerevisiae and Hansenula anomala using Mucor Nuruk was compared with distillate from mashes brewed with Andong Nuruk and with distillate from plant fermented mashes to analyze their flavor characteristics. The volatile flavor compounds in distillates were analyzed by GC and GC-MS using direct injection, solvent extraction, and purge & trap methods. Alcohols such as 3-methyl-1-butanol, 2-methyl-1-propanol, 1-propanol, and 2-phenyl ethanol; aldehydes such as acetaldehyde and 2-furancar-boxaldehyde; esters such as ethyl ester of acetic acid, hexanoic acid, octanoic acid, decanoic acid; alkanes, alkenes, ketone, sulfur, and pyrone compounds were detected. Alcohols were chief components of flavor compounds. No significant difference in overall acceptability test was shown among three experimental groups(p<0.05), but Nuruk-like aroma, Kaoliangchiew-like aroma, sweet taste, and well rounded mouthfeel showed significant differences among them(p<0.05).

• Preventive Nutrition and Food Science
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• v.16 no.1
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• pp.45-54
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• 2011

Volatile components in commercial pine needle (Pinus densiflora S. and Z.) powder were extracted using simultaneous steam distillation and a solvent extraction (SDE) apparatus, and were analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 230 compounds divided into 13 groups were identified, which included alcohols (42), ketones (39), aldehydes (32), terpenes (30), alkenes (17), esters (14), furans (14), benzenes (10), alkanes (8), napthalenes (7), acids (6), miscellaneous compounds (6), and phenols (5). Among the 230 compounds identified, 96 compounds were positively confirmed and quantified, and the rest of the compounds were tentatively identified. The major volatile components identified at relatively high levels were dodecanoic acid, hexadecanoic acid, hexanal, benzaldehyde, (Z)-3-hexen-1-ol, 1-penten-3-one, limonene, and $\beta$-caryophyllene oxide. Among the groups, terpenes accounted for 60.18% of the total concentration of all the volatile components. Some volatile components might account for the unique aroma and the biological activity of the sample.

• The Korean Journal of Community Living Science
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• v.24 no.2
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• pp.243-249
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• 2013

Identification of coating film species from ancient coating materials is needed to maintaine their surfaces without loss of their original beauty for a long time and understand the historical background of manufacturing techniques. A pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was applied to identify the origine of films in ancient coating materials. The pyrolysis products, which reflect the source from which they originate were detected distinctively at $500^{\circ}C$. This is a rapid technique that does not require large amounts of sample or any sample preparation. Sesquiterpenes are a class of terpenes that consist of three isoprene units were identified as cadienes, selinenes, cubebenes from the raw material of dendropanax morbifera. On the other hand, alkanes(tetra~heptadecanes), alkenes (tri~heptadecenes), allkyphenols, catechols and fatty acids were detected from the raw material of the lacquer film. Based on these results, the origine of historic coatings artifacts was identified using py-GC/MS by comparison with their pyrolysis products.

• Journal of ILASS-Korea
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• v.23 no.2
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• pp.66-73
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• 2018

Volatile organic compounds (VOCs) are well known as ozone precursors from photochemical reactions and contribute to the formation of photochemical smog which pose health hazards. Also, some of these compounds directly affect the human health due to their toxicity such as benzene. In this study, NMVOCs composition in exhaust gas from recreational vehicle (RV) and (MPV) were characterized using a chassis dynamometer. The results for NMVOCs have reported that alkanes emission was higher than alkenes, aromatics and cycloalkanes due to reactive of diesel oxidation catalysts. The NMVOCs composition according to carbon number was highly distributed between C3 and C6~C8. During the engine cold start condition, NMVOCs emission was higher compared to the engine hot start condition due to the increased catalytic activity. The NMVOCs emission with DPF increased compared to that without DPF. The results of this study will be provide to calculate VOCs emissions from mobile source.

• Journal of ILASS-Korea
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• v.23 no.2
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• pp.74-80
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• 2018

Emission characteristics of regulated pollutants (CO, NOx, HC and PM) and hazardous air pollutants (HAPs) from diesel heavy duty trucks equipped with EGR+pDPF and SCR for Euro 5 emission standards were investigated using a chassis dynamometer. In the case of regulated pollutants, diesel heavy duty trucks with EGR+pDPF emitted 79% less CO than those with SCR. Also, those with the SCR emitted 36% less NOx than those with the EGR+pDPF. The results of VOCs have show that alkanes emissions for heavy duty trucks with the EGR+pDPF and the SCR have been higher than alkenes, cycloalkanes and aromatics. In the case of individual VOCs, the highest of propene emissions for 11.3~16.1% occupied. For aromatics group, benzene emissions are the highest percentage for 4.4~15.5%. In the future, the results of present study will provide basic data to set up HAPs emissions inventory for mobile source.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1702-1708
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• 2002

The synthesis and catalytic application of a new class of a new class of planar chiral ferrocenes, 1,2-ferrocenediylazaphosphinines (1 and 2) are described. They are powerful ligands for the copper(I)-catalyzed asymmetric cyclopropanation of a range of alkenes with diazo esters to exhibit an exceptionally high degree of diastereoselectivity(~100% de) in favor of trans isomers, regardless the structure of the olefins and the diazo compounds. Comparative studies between 1 and 2 reveal that the former works better in terms of diastereocontrol. In contrast, however, enantioselectivity is low with both 1 and 2 as a whole although, in certain cases with a proper combination of the olefin and the diazo ester, high optical yields (up to 100% ee) can be achieved. Other reaction parameters such as the reaction temperature and the structure of the ligand do exhibit some influence, although infinitestimal, on both chemical and optical yields.