• Proceedings of the KSR Conference
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• 2002.10b
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• pp.943-947
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• 2002

Volatile Organic Compounds(VOCs) contribute to the formation of ozone and PAN which are injurious to health through complex photochemical reactions. Growing consumption of fossil fuels results in significant emission of VOCs and other air pollutants into the atmosphere. This study was carried out to evaluate of Volatile Organic Compounds(VOCs) concentrations in Kumi industrial complex. Ambient air sampling was determined at five sites from August to September in 2002. The Volatile Organic Compounds samples were collected using the silicocan canisters, and were determined by GC/MS which connected preconcentrator system. The Kumi industrial complex of VOCs concentrations were generally similar with Yeochun's but some of VOCs concentrations of Kumi were higher than Yeochun industrial complex's. Also the industrial area was higher than downtown and residential district.

• Particle and aerosol research
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• v.7 no.1
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• pp.1-8
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• 2011

In this study, the formation of nanoparticles by a reaction of ozone with the volatile organic compounds(VOCs) emitted from a commercial home cleaner liquid was investigated using a $1-m^3$ reaction chamber($1{\times}1{\times}1m$). The home cleaner liquid was found to contain many VOCs, particularly terpenes. Some of these VOCs are known to readily react with ozone, forming indoor secondary pollutants. The correlation of particle concentration and reacted ozone concentration was examined with injections of three different ozone concentrations; 50, 100 and 200 ppb. The secondary nanoparticles were formed faster, with their numbers and mass concentrations becoming higher on increasing the concentration of ozone injected.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.16-23
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• 1998

Effect of Fermentation temperature on the changes of chemical components in Kakudgi during fermentation was investigated by measuring free sugar, organic acid and volatile compounds up to 57 days at several temperatures. The mannitol was increased in palatable period in contrast with those of other free sugars. The higher the initial fermentation temperature was and the longer the initial fermentation time at 2$0^{\circ}C$ was, the faster the second increasing period was and the less the initial contents was. Lactic acid was increased 6~31 times from a little amount at the initial period. The higher the initial fermentation temperature was and the more the increasing content was. But malic acid which was abundant(55.1% of total nonvolatile organic acid) in the initial fermentation period was remarkably decreased in the palatable period. The change of the sulfides among the volatile compounds was remarkable. Methyl allyl sulfide which was a little in the initial fermentation period was remarkably increased in the final fermentation period, and the correlation coefficients between the content of methyl allyl sulfide and aroma in sensory evaluation were high. It could be suggested that the fermentation temperature should be set to 4$^{\circ}C$ after fermentating at 2$0^{\circ}C$ for 36 hours in the view point of keeping the Kakdugi taste and quality well because of high content of free sugar and nonvolatile organic acids.

• Korean Journal of Materials Research
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• v.30 no.10
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• pp.515-521
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• 2020

Organic-inorganic hybrid perovskite nanocrystals have attracted a lot of attention owing to their excellent optical properties such as high absorption coefficient, high diffusion length, and photoluminescence quantum yield in optoelectronic applications. Despite the many advantages of optoelectronic materials, understanding on how these materials interact with their environments is still lacking. In this study, the fluorescence properties of methylammonium lead bromide (CH₃NH₃PbBr₃, MAPbBr₃) nanoparticles are investigated for the detection of volatile organic compounds (VOCs) and aliphatic amines (monoethylamine, diethylamine, and trimethylamine). In particular, colloidal MAPbBr₃ nanoparticles demonstrate a high selectivity in response to diethylamine, in which a significant photoluminescence (PL) quenching (~ 100 %) is observed at a concentration of 100 ppm. This selectivity to the aliphatic amines may originate from the relative size of the amine molecules that must be accommodated in the perovskite crystals structure with a narrow range of tolerance factor. Sensitive PL response of MAPbBr₃ nanocrystals suggests a simple and effective strategy for colorimetric and fluorescence sensing of aliphatic amines in organic solution phase.

• Textile Coloration and Finishing
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• v.33 no.3
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• pp.153-160
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• 2021

In this study, composite materials were prepared by varying the content of glass fiber and bamboo fiber in PP/glass fiber/bamboo fiber. Experiments were conducted to confirm the mechanical properties(tensile, impact and burst strength) and volatile organic compound content of the bamboo fiber composite prepared under these conditions. An improvement in the main properties was observed at a fiber content of 30wt%. When the fiber fraction was increased above 30wt%, the mechanical properties tended to decrease due to the agglomeration of fibers at higher load fractions. In addition, the content of volatile organic compounds increased as the content of bamboo fibers increased, which is thought to be due to the volatile organic compounds generated during the manufacturing process of the composite material being present in the composite material without escaping from the pores of the bamboo fibers and volatilizing at a certain temperature. As a result of confirming the physical properties of the composite, it is considered that the optimal mixing condition is 30wt% of bamboo fiber for the composite produced by varying the amount of bamboo fiber composite. In the future, it is thought that follow-up experiments to confirm and improve the pre-treatment conditions for reducing the content of volatile organic compounds in the manufactured composite material are possible.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.885-891
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• 2005

The study was carried out to find the effect of freeze drying on the volatile organic components in garlic (Allium sativum L.). The volatile organic compounds from fresh and freeze dried garlic were extracted by simultaneous steam distillation and extraction (SDE) method and identified with GC/MS analysis. A total of 42 and 32 compounds were identified in fresh and freeze-dried garlic, respectively. Sulfur containing compounds in the garlic samples were detected as the major compounds, and alcohols, aldehydes and esters were detected as minor compounds. Diallyl disulfide, diallyl trisulfide, allyl methyl disulfide and ally1 methyl trisulfide were the main sulfur compounds in fresh and freeze dried garlic. The amount of sulfur containing compounds were decreased freeze-drying but methyl propyl trisulide, 3- allylthiopropionic acid, cyclopentyl ethyl sulfide etc. were increased. The others, non- sulfur containing compounds such as ethyl acetate, ethanol, 2-propenol, 2- propenal and hexanal were increased in freeze-dried garlic. Consequently, the total amount of volatile organic compounds in garlic became lower during freeze-drying from 853.42 mg/kg to 802.21 /kg, and the composition of major components were nearly same in fresh and freeze-dried garlic.

• Analytical Science and Technology
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• v.7 no.1
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• pp.125-132
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• 1994

Flavours in kimchee are the result of unique combination of various sugars, organic acids and amino acids as well as various volatile organic compounds including sulfur-containing compounds, terpenes, alcohols, and some volatile organic acids. In the experiment for the flavour extracting methods, dynamic headspace(DHS) is more effective for collection of volatile flavour than simultaneous distillation extraction(SDE). The best polarity available at the moment is 5% phenyl methyl poly-siloxane which will separate non-polar, intermediate and polar components with good resolution.

• KSBB Journal
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• v.29 no.5
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• pp.392-398
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• 2014

It was confirmed that malodor connected with an air-conditioner in an automobile is caused by microbial volatile organic compounds (MVOCs) produced by microorganisms and through microorganisms coexisting with each other to form a biofilm on the evaporator surface. A bacterium, Methylobacterium aquaticum, can form a biofilm on the evaporator surface. The biofilm was composed of 45.79% C (Carbon), 42.36% O (Oxygen), 1.85% Na (Sodium), 5.42% Al (Aluminum), 1.39% P (Phosphorus), 0.74% Cl (Chlorine) and 2.45% K (Potassium). This result matches the composition of the biofilm formed on the surface of the used evaporator. It was determined that sulfur compounds (Hydrogen sulfide, Dimethyl sulfide) and organic acids (n-Butyric acid, n-Valeric acid, iso-Valeric acid) in the air which was blown into the automobile were generated by Methylobacterium aquaticum and Aspergillus versicolor, respectively. On the other hand, volatile organic compounds (Toluene, Xylene, 2-Ethylhexanol, 2-Phenyl- 2-propanol, Ethylbenzene) were not found. It is estimated that the reason is due to the low concentration of generated MVOCs or is caused by the change of some MVOCs depending on the nutrients (medium).

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.305-308
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• 2012

In this study, we evaluated antifungal and antioxidant activities of condensed liquid of volatile organic compounds generated during the drying process of Chamaecyparis obtuse. Condensed liquid of volatile organic compounds were extracted with hexane and ethyl acetate, respectively. The extracts were used for antifungal activity at range from 100 to 500 mg/L Antifungal activity of extracts increased as the extracts concentration increased, the activity against tested dermatophytes was high at 500 mg/L. Among extract solvents, antifungal activity was higher at hexane extract than the ethyl acetate. Especially, the antifungal activity against Trichophyton rubrum was higher than other tested dermatophytes. Antioxidant activity was 90% above 25 mg/L regardless of the extractive solvents, while the hexane extract showed high antioxidant activity below 25 mg/L. Major compounds of hexane extract were torreyol, alpha-cadinol, and tau-cadinol. However, major compounds of ethyl acetate extract were alpha-amorphene, alpha-cadinol, and gamma-cadinene.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.219-227
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• 1995

Natto is a Japanese tradiational food made from whole soybeans by the fermentation of Bacillus natto. This study was attempted to improve the taste of Natto, garlic(2%) and red pepper oleoresin(0.2%) were added. Conventional Natto(N-1), garlic Natto(N-2), red pepper oleoresin Natto(N-3), garlic and red pepper oleoresin Natto(N-4) were prepared. Volatile flavor components, fatty acid, organic acid, pH and titratable acdity in all samples were investigated. The experimental results revealed the presence of 62 volatile components in conventional Natto. Among there, the major flavor compounds were identified to be 2, 5-dimethylpyrazine, trimethyl-pyrazine, 2, 6-bis91, 1-dimethylethyl) phenol. Seventy-one volatile compounds were detected in N-2, and major compounds were identified to be methyl-2-propenyl disulfide, 2, 6-bis(1, 1-dimethylethyl)phenol and 2, 5-dimethylpyrazine. The amounts of volatile compounds, 2-methyoxyphenol and 1, 2-benzenedicarboxylic acid increased by addition of garlic, where as, 1,2 -propanediol, 1-hexanol and 2, 5-dimethylpyrazine decreased. The compounds, 4, 5-dihydroxy-5-propyl-1H-pyrazole, 1, 1, 3-trimethylcyclopentane were identified in N-3. The compounds, such as trimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine increased by addition of red pepper oleoresin, whereas 1,2-propanediol, 1-hexanol and 2,5-dimethylpyrazine decreased. Fatty acid compositions were mainly consisted of linoleic acid(43.66~55.89%) and followed by oleic, palmitic, linolenic, stearic, arachidic, myristic acid. The organic acids we4re identified to be citric(28.2~30.6), acetic(50.0~73.3) and pyroglutamic acid(2.1~3.7).