• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.28-32
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• 1998

Two organophosphorous insecticides, Dichlorovos and Chloropyrifos were degraded in the presence of UV irradiation, UV irradiation with $TiO_2$ powder and UV irradiation with sea sand using low pressure mercury lamp. The identification of these compounds was carried out by gas chromatograph with a nitrogen-phosphorous detector, Total Organic Carbon and Ion Chromatograph, respectively. Both dichlorvos and chloropyrifos, UV irradiation with sea sand were more degradable than UV irradiation and UV irradiation with $TiO_2$ powder. The final products were $Cl^-$ in Dichlorvos, $Cl^-$ $SO_4{^{2-}}$ in Chloropyrifos, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.384-387
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• 2005

Fuel cell has been well known as a clean alternative power for vehicles. Recently, an experimental technique has been developed measurement of species and distributions by using gas chromatograph. In this study, cathode channel oxygen distributions as various conditions were investigated using gas chromatograph and cell visualization. And discussed relation between flooding and oxygen concentrations. As a result of experiment, oxygen consumpt ion is affected wi th flooding. Flooding is observed in channel near hydrogen inlet, and oxygen consumption is low at that region.

• Journal of the Korean Institute of Gas
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• v.11 no.4
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• pp.7-11
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• 2007

There has been a report of fire and explosion accident in regenerated thermal oxidizer (RTO). This paper was to investigate accident causes of RTO in the resin re-treatment process. The experiments carried out physicochemical properties and thermal stability analyses by using flash point tester, flammable range apparatus, autoignition tester, GC/MSD and thermal screening unit. We inferred causes of fire and explosion from the regenerated thermal oxidizer to prevent an accident of its process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.483-486
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• 2000

In the recognition of the gases using the quartz crystal rnicrobalance (QCM) coated with the film materials, it is important to obtain the recognition ability of gases, and the stability of film coated above the QCM. Especially, the thickness of film coated above the QCM is decreased according with the using circumstance and time of QCM gas sensor. Therefore, the sensing chararcteristics of film is changed with these. In this paper, we coated the lipid GC materials varing with the blended amount of PVC(Po1y Vinyl Chloride) and solution (Tetra Hydrofan:THF) above QCM to obtain the stability of lipid PC film. QCM gas sensors coated with film materials were measured the frequency change in the chamber of stationary gas sensing system injected 1-hexane, ethyl acetate, ethanol and benzene of 20.4 respectively. Also, we measured the degradation characteristics of QCM gas sensor to show the properties of stability.

• Journal of Korea Soil Environment Society
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• v.3 no.2
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• pp.3-12
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• 1998

To analyze of oils in contaminated soils, it is necessary to classify of oils accurately and it has to be selected suitable extraction method and instrumental analysis method in according to the character of sample. In this study, oils are classified into three groups-gasoline, diesel and kerosene-we consider extraction methods and quantitative analysis method of these oils using GC/MS. As the analysis example of real sample, we analyze some gasolines and diesels of some oil refining company and calculate BTEX in gasoline and saturated n-hydrocarbons in diesel. And also, we study the representative quantitative method of each kind of oils.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.151.2-151.2
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• 2010

본 연구는 하이드로퀴논(HQ)을 이용하여 매립가스로부터 이산화탄소를 선택적으로 분리하고 유기 크러스레이트 형태로 분리 및 저장에 적용하기 위한 연구로써 하이드로퀴논을 다양한 객체가스와 반응시키면서 열역학적 안정영역을 파악하고 분광학적 방법을 이용하여 미세구조 변화를 분석하고자 하였다. 먼저 ${\alpha}$-HQ를 고압(4MPa)의 이산화탄소와 반응시켜 이산화탄소가 포집된 ${\beta}$-HQ를 합성하였고, 동공 내에 존재하는 이산화탄소를 제거하여 동공을 유지하는 empty ${\beta}$-HQ를 만들었다. 온도를 증가시키면서 XRD 패턴을 측정한 결과 298 K 에서 378 K 사이에서 ${\beta}$-HQ 시료는 서서히 empty ${\beta}$-HQ 의 구조로 전환되었으며 378 K 이상의 온도에서 ${\alpha}$-HQ 구조로 급격히 전환되었다. 또한 생성된 empty ${\beta}$-HQ 동공에 이산화탄소가 포집, 해리되는데 있어서 온도의 영향을 확인하기 위해 298K과 343K의 온도에서 실시간 라만분광법으로 측정하였다. 그 결과 298K에서 약 200분의 시간이 지난 후 이산화탄소는 하이드로퀴논 동공 내로 포집되어 안정화되었으며 압력해방 후에는 빠져나가지 않고 동공 내에 존재함을 확인하였다. 그러나 343K에서는 급격히 포집되어 30분 이내 안정화되었고, 압력해방 후 동공 내에 존재하지 못하고 빠져나가는 것을 확인하였다. Empty ${\beta}$-HQ의 이산화탄소 선택도를 관찰하기 위해 이산화탄소와 메탄, 수소, 질소의 조성이 각각 30%, 30%, 20%, 20%인 혼합가스와 반응시킨 후 가스 크로마토그래프 분석을 실시한 결과, empty ${\beta}$-HQ내 포집된 가스 중 이산화탄소의 조성이 약 80% 이상으로 나타나 높은 선택도를 나타냄을 관찰하였다.

• Journal of Food Hygiene and Safety
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• v.39 no.2
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• pp.152-162
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• 2024

In this study, we investigated the levels of the natural preservatives, benzoic acid, sorbic acid, and propionic acid, in raw unprocessed vegetables. Quantitative analysis of benzoic acid and sorbic acid was performed using high-performance liquid chromatography with a diode array detector (HPLC-DAD) and confirmed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Propionic acid was analyzed using a gas chromatography-flame ionization detector (GC-FID) and confirmed using gas chromatography-mass spectrometry (GC-MS). From a total of 497 samples, benzoic acid, sorbic acid, and propionic acid were found in 50 (10%), 8 (0.2%), and 61 samples (12.3%), respectively. The highest quantity of benzoic acid, sorbic acid, and propionic acid was found in peony root (1,057 mg/kg), nut-bearing torreya seeds (27.3 mg/kg), and myrrha (175 mg/kg), respectively. The background concentration range of naturally occurring preservatives in raw vegetables determined in this study could be used as standard inspection criteria to address consumer complaints and trade disputes.

• Journal of the Korean Chemical Society
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• v.42 no.5
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• pp.526-530
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• 1998

Analysis of trace impurities in the gases has been very important with the development of semi-conductor related industry. Particularly, the contamination of the gas handling systems in a semi-conductor plant by the air has been a trouble to the manufacturers. Thus, the analysis of the air components in the system has been a task to the analysts. In this study, we report the analysis data with a expanded uncertainty for the trace impurities of nitrogen and argon in the bulk helium and hydrogen. All data show a good correspondence, exhibiting reliable statistical error ranges.

• Analytical Science and Technology
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• v.13 no.1
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• pp.101-107
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• 2000

The automotive paints could be generally differentiated by color, layer sequence and chemistry of the paint layers comprising each of the topcoat and the primer system. The successful identification of hit-andrun a and traffic accidental vehicles from evidential paint fiagments is greatly facilitated with a comprehensive laboratory collection of reference paint samples and the technique for direct analysis without sample preparation. The Pyrolysis-Gas Chromatography(PGC) is a precise and reliable method for performing both quantitative and qualitative analysis of polymeric materials and forensic samples. Our Forensic Laboratory is conducting the examination and identification of 73 reference paint samples; 4 colors of each domestic automotive make that is popular in Korea, by Curie Point Pyrolyzer(JHP-3) and GC with capillary column(ultra alloy-5). This method can be used not only to compare paint traces with their suspected sources, but also to identify the type, make and model of the automotive car.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.30-34
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• 1999

Photolysis behavoirs of pesticides(Chlorothalonil and Endosulfan) over UV irradiation UV irradiation with pH 3.0 and irradiation with 3.5% salt were studied. The analyses of pesticides were carried out using gas chromatograph with an electron-capture detector, total organic carbon, and Ion chromatograph, respectively. The reactions were conducted in a alumium annular reactor equipped with a low pressure mercury multilamp ($8W{\times}6$) and initial concentration was 10 ppm. Chlorothalonil was almost photodegraded by UV irradiation, UV irradiation with pH 3.0 and 3.5% salt within 30 min of reaction time. Endosulfan-${\alpha}$,${\beta}$(100%) were photodegraded to 38% of Endosulfan-${\alpha}$ and 25% of Endisulfan-${\beta}$ by UV irradiation. Endosulfan-${\alpha}$(83%) was photodegraded to 66% by UV irradiation, 70% by UV irradiation and pH 3.0 and 75% by UV irradiation and 3.5% salt. Endosulfan-${\beta}$(16%) was photodegraded to 80% by UV irradiation, 98% by UV irradiation and pH 3.0 and 90% by UV irradiation and 3.5% salt.