• Environmental Analysis Health and Toxicology
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• 제17권2호
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• pp.117-123
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• 2002

A gas chromatographic method for the determination of airborne formaldehyde was established. In order to be highly detectable with the electron capture detector, formaldehyde was derivatized to its pentafluorobenzyl oxime form by reacting with O- (2,3,4,5,6- pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) at pH of 4.6 and temperature of 50$^{\circ}C$ for 1 hour. Air samples were collected into a Tedlar$\^$(R)/ bag followed by transferring into water contained in two impingers in series. Collection efficiency in the front trap was higher than 90％. Measurement of selected indoor and outdoor air samples showed higher formaldehyde concentrations in indoor air environments and the importance of ventilation for reducing indoor pollution.

• 한국막학회:학술대회논문집
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• 한국막학회 1996년도 추계 총회 및 학술발표회
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• pp.43-44
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• 1996

Water-swollen-hydrogel membranes for gas separation were prepared by dipcoating and thermal crosslinking of poly(vinylalcohol) (PVA) - poly(acrylacid) (PAA) blends on asymmetric porous polyetherimide(PEI) supporters. The polyetherimide supporters, prepared by phase inversion of polyetherimide solutions in N-methylpyrrolidone(NMP) (composition of PEI/NMP=25/75), had good heat and chemical resistane. The coating materials with different blending ratios of PVA/PAA(=90/10, 80/20, 70/30) were characterized with differential scanning calorimetry (DSC), infrared spectroscopy(IR) and the water swelling ratios. The permeabilities and the separation factors of carbon dioxide through these membranes were measured by a mass flow meter and gas chromatograph at different temperatures, respectively, under a vacuum mode of downstream.

• Journal of Pharmaceutical Investigation
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• 제6권2호
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• pp.83-87
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• 1976

Microanalysis of rodenticide by visible absorption method was attempted. The following procedure was found to be very simple and to give accurate results. RH-28787 was added to dimethylformamide (DMF), and extracted after stirring for about 20 minutes in extractor $(30^{\circ}C)$. After extraction, the absorbance of DMF solution, was measured at 346 nm by using spectrophotometer. The result agrees closely with the experimentally determined value by means of the gas chromatograph.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 공동학술발표회
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• pp.207-207
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• 2017

• Journal of Mechanical Science and Technology
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• 제19권12호
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• pp.2197-2204
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• 2005

The combination of Gas chromatography (GC) for separation and Flame Ionization Detection (FID) for detection and identification of the components of a mixture of compounds is a fast and strongly proved method of analytic chemistry. The objective of this research was to design a combined High-speed miniature screening Gas chromatograph along with a Flame Ionization Detector for quick, quantitative and qualitative analysis of gas components. This combined GC-FID system is suitable to detect the volatile and semi-volatile hydrocarbons present in a gas mixture. The construction made it less expensive, easy to use and movable. The complete gas path was developed. On/off valves, temperature and flow sensors and their interface electronics were used for controlling purpose. A Microcontroller was programmed to measure the temperature and gas flow using the sensors and to control and regulate them using the electronics and valves. A pocket PC with its touch screen served as a user interface for the system. Software was developed for the pocket PC, which makes the communication possible with the Microcontroller. The system parameters can be indicated in the Pocket PC as simple text and also the analysis result can be displayed.

• 공업화학
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• 제9권1호
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• pp.28-32
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• 1998

두 종류의 유기인계 살충제인 디클로로보스와 클로로피리포스를 UV조사, UV 조사와 $TiO_2$분말 그리고 UV조사와 sea sand를 저압수은 램프를 이용하여 분해실험을 하였다. 이 화합물의 확인은 가스크로마토그래프, 총유기탄소 그리고 이온크로마토그래프를 사용하였다. 두 물질 모두, UV조사와 sea sand가 UV 조사와 UV조사와 $TiO_2$분말보다 분해가 더 잘 되었다. 반응 최종생성물은 디클로르보스에서는 $Cl^-$, 클로로피리포스에서는 $Cl^-$ $SO_4{^{2-}}$등이 생성되었다.

• Journal of Biosystems Engineering
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• 제31권5호
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• pp.443-448
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• 2006

For development of an on-line monitoring unit of fermentation process, an auto dilution unit based on traditional chemical and biological analytical method was developed and the performance was evaluated. The dilution unit was constructed with two syringe pumps and flow direction change valves and fully automated. Total delivery volume of two pumps using distilled water was measured to confirm the operating stability And diluted concentrations of three substrate solutions (glucose, lactic acid, ethanol) were compared with a standard method with a high performance liquid chromatograph (glucose, lactic acid) and gas chromatograph (ethanol). Relative error values of total delivery volume of the pumps were below 3% and standard deviation values were 0.003 (n=5). Relative error values of diluted concentration of the dilution unit measurements were below 2% with 1/10 of dilution ratio and 70, $80{\mu}{\ell}$ of sample volume conditions for glucose and lactic acid, 1/30 of dilution ratio and $70{\mu}{\ell}$ of sample volume conditions for ethanol, respectively. In case of the ethanol, cause of the evaporative characteristics, the relative error values showed over 5% whole experimental conditions.

• Journal of Korean Society for Atmospheric Environment
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• 제19권E2호
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• pp.89-97
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• 2003

Ambient polycyclic aromatic hydrocarbons (PAHs) were measured during the winter and summer of 2002 in Chongju. A filter pack and polyurethane foam (PUF) system was employed to collect simultaneously the particulate and gas phase PAHs. The samples were then analyzed using a gas chromatograph equipped with mass spectrometer detectors (GC/MSD). A total of 29 samples were collected and 11 PAH species were identified. The lower molecular weight PAH compounds (3∼4 rings) dominated the total PAH mass. The higher molecular weight PAH compounds (5∼6 rings) were less abundant. The PAHs were showed to exhibit seasonal variations. The concentrations of all com-pounds were significantly higher in winter than summer. The lower molecular weight PAHs were mostly found in the gas phase whereas the heavier ones were mainly associated with particulate phase. Vehicle emissions are likely to be the primary contributor of PAHs in Chongju. This study also demonstrated that it is necessary to perform simultaneously particulate and gas phase measurements to determine the accurate concentrations of ambient PAHs.

• 대한한방내과학회지
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• 제35권4호
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• pp.532-545
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• 2014

Objectives: The purpose of this study was to evaluate the clinical effect of Korean medical treatments such as herbal medicine, acupuncture, and electroacupuncture by using the portable gas chromatograph OralChroma$^{TM}$ (Abimedical, Japan) in halitosis patients. Methods: We surveyed 30 halitosis patients who had visited the Oral Diseases Clinic in the Korean Medical Hospital of Kyunghee University from October, 2013 to November, 2014. Before starting Korean medical treatment, the subjects were evaluated on sociodemographic characteristics, severity of discomfort using visual analogue scale (VAS), unstimulated salivary flow rate (USFR), and halitosis associated life-quality test (HALT) score. To evaluate the therapeutic effect, we measured the volatile sulfur compounds (VSCs) in breath by using OralChroma$^{TM}$ before and after 3 weeks treatment. Results: The concentration of total VSCs measured by OralChroma$^{TM}$ significantly decreased (p=0.001). Furthermore, the level of hydrogen sulfide and methyl mercaptan also significantly decreased (p<0.05). However, although the level of dimethyl sulfide decreased as well, there was no significance(p>0.05). Conclusions: Korean medical treatment was effective in treating halitosis by decreasing VSCs. Further study, with well-designed randomized controlled trials with larger number of cases will be needed in the future.

• Applied Biological Chemistry
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• 제15권1호
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• pp.7-17
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• 1972

전국(全國) 12도시(都市)의 15개(個) 시장(市場)에서 수집(蒐集)한 감자, 무우, 배추와 기타(其他) 10종(種)의 채소등(菜蔬等) 총(總) 151점(點)의 객관적(客觀的) 시료(試料)에 대(對)한 Heptachlor잔류분(殘留分)의 수준(水準)을 gas chromatograph로 분석(分析)하였다. Heptachlor 및 Heptachlor epoxide의 분석감도(分析感度)는 0.001 p.p.m. 였고, 식품중(食品中) 양(兩) 잔류성분(殘留成分)의 화(和)를 Heptachlor잔류분(殘留分)(p.p.m.)으로 하였다. 공시채소(供試菜蔬)의 Heptachlor오염(汚染)이 광범(廣範)한데 반(反)하여, 전체적(全體的)인 Heptachlor 잔류분(殘留分)의 수준(水準)은 낮은 결과(結果)를 보여 주어, FAO/WHO의 합동전문위원회(合同專門委員會)가 권장한 식품중(食品中) Heptachlor잔류허용한계(殘留許容限界)에 훨씬 미달(未達)하였다.