• Analytical Science and Technology
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• v.35 no.6
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• pp.249-255
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• 2022

In this study, a new method for the analysis of high-purity nitrogen was developed. A gas chromatography-flame ionization detector (GC-FID) was used for purity analysis. Certified reference materials (CRMs) at a level of 3 µmol/mol of carbon monoxide (CO), carbon dioxide (CO₂), and methane (CH₄), which may exist in high-purity nitrogen, were prepared using the gravimetric method, and these CRMs were used for purity analysis. In this new method, ultra-high-purity and high-purity nitrogen were used as carrier gases. The impurities in high-purity nitrogen were quantitatively analyzed by comparing the differences in the area values of the GC chromatograms of the prepared CRMs. We purchased liquid nitrogen and three bottles of nitrogen gas, which were produced by three different manufacturers, using high-purity nitrogen. Furthermore, to validate the developed purity analysis method, the fraction of impurities in high-purity nitrogen was compared with the results of the typical purity analysis method. The comparison results were consistent within the expanded uncertainties (k = 2).

• Journal of the Korean GEO-environmental Society
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• v.11 no.5
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• pp.61-67
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• 2010

In this study, Solid-phase microextraction (SPME) with GC/FID was studied as a possible alternative to liquid-liquid extraction for the analysis of chlorinated solvents (PCE and TCE) and these by-products (cis-DCE, VC, and Ethylene). Experimental parameters affecting the SPME process (such as kind of fibers, adsorption time, desorption time, volume ratio of sample to headspace, salt addition, and magnetic stirring) were optimized. Experimental parameters such as CAR/PDMS, adsorption time of 20 min, desorption time of 5 min at $250^{\circ}C$, headspace volume of 50mL, sodium chloride (NaCl) concentration of 25% combined with magnetic stirring were selected in optimal experimental conditions for analysis of chlorinated solvents and these by-products. The general affinity of analytes to CAR/PDMS fiber was high in the order PCE>TCE>cis-DCE>VC>Ethylene. The linearity of $R^2$ for chlorinated solvents and these by-products was from 0.912 to 0.999 when analyte concentrations range from $10{\mu}g/L$ to $500{\mu}g/L$, respectively. The relative standard deviation (% RSD) were from 2.1% to 3.6% for concentration of $500{\mu}g/L$ (n=5), respectively. Finally, the limited of detection (LOD) observed in our study for chlorinated solvents and these by-products were from $0.5{\mu}g/L$ to $10{\mu}g/L$, respectively.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.313-314
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• 2000

최근들어 유해한 작업환경의 대기나 공장의 배기 가스, 또는 주변 주거 지역의 대기에서 검출되는 인체 유해 물질들에 많은 관심이 모아지고 있다. 이들 물질 중 휘발성 유기오염물(VOC)은 대기 중에 매우 낮은 농도로 존재하기 때문에 이의 측정은 매우 중요시되고 있다. 휘발성 유기화합물(VOC)의 분석 방법에는 GC-MS 또는 GC-FID에서 정확하게 측정하기 위하여 저온 농축법을 이용한 분석방법이 있으며 이들 두 가지 방법은 각각의 저온 농축시스템은 조절이 어렵고 작동하기가 복잡하다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.315-316
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• 2000

유해한 작업 환경지역, 공장밀집 지역 또는 주변 주거 지역의 대기에서 발생하는 악취성분 및 휘발성유기화합물은 환경규제 물질로 분류되고 국내적으로도 이들의 검출 및 정확한 정량적 분석을 위한 연구가 활발하게 진행되고 있다. 일반적으로 이들 성분들은 대기중에 미량으로 존재하기 때문에 흡착관 및 canister등에 의한 시료의 포집을 행하고 이들 분석시료를 실험실에서 저온농축과정을 거쳐 GC/FID 혹은 GC/MS등을 사용하여 정량분석을 실시한다. (중략)

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.354-357
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• 2004

The addition of oxygenates to diesel fuel can significantly reduce particulate emissions. Dibutyl maleate (DBM) and tripropylene glycol methyl ether (TGME) have been identified as possible additives based on their physicochemical characteristics and performance in engine test. However, their potential environmental impacts are unknown. therefore, practical considerations in the selection of an oxygenate additives should include cost, availability, compatibility with engines and fuel, and, particularly, its overall environmental impact. This study was investigated to determine optimal condition for the analysis of potential diesel oxygenates using SPME technique with GC-FID. Four fibers were compared and CAR/PDMS fiber was found to be the most sensitive when used direct-sampling. An absorption time of 30min and a desorption time of 5min provided to be the most sensitivity. The effects of experimental parameters such as the addition of salts, agitation, absorption time, compositon on the analysis were investigated. Analytical parameter such as linearity was also evaluated.

• Bulletin of the Korean Chemical Society
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• v.21 no.11
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• pp.1101-1105
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• 2000

A simultaneous determination method of BTEX (benzene, toluene, ethylbenzene, o,m.p-xylene) and TPH (kerosene, diesel, jet fuel and bunker C) in soil with gas chromatography/flame ionization detection (GC-FID) was described. The effects of extracti on method, extraction solvent, solvent volume and extraction time on the extraction performance were studied. A sonication method was simpler and more efficient than Soxhlet or shaking methods. Sonication with 10 mL of acetone/methylene chloride (1 : 1, v/v) for 10 min was found to be optimal extraction conditions for 20 g of soil. Peak shapes and quantification of BTEX and TPH were excellent, with linear calibration curves over a wide range of 1-500 mg/L for BTEX and 10-5000 mg/L for TPH. Good reproducibilities by sonication were obtained, with the RSD values below 10%. By using about 20 g of soil, detection limits were 0.8 mg/L for BTEX and 10 mg/L for TPH. The advantages of this procedure are the use of simple and common equipment, reduced volumes of organic solvents, rapid extraction periods of less than 20 min, and simultaneous analysis of volatile and semivolatile compounds.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.603-608
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• 2009

In this study, "Hongro" apples for test samples were selected from a market for aroma analysis. Analysis was done after 1 hr, in a forming headspace while maintaining a temperature of $25^{\circ}C$. First, the complex aroma of the apples was assessed by a Direct Sensory Method. Secondly, the complex aroma was analyzed under individual aroma conditions separated by GC/FID/Olfactometry. Finally, aroma component analysis by GC/MS was performed. Degrees of contribution of aroma components were evaluated by an aroma value calculation considering aroma duration time, frequency, and intensity. The contribution rate (%) of the aroma induction component influencing apple aroma was determined by aroma component analysis and aroma contribution degree. As a result, it was found that the top four components were as follows, by contribution rate (%): acetic acid (23%), 1-hexanol (16%), butyl ethanoate (13%), 4-methoxy-2-methylbutane (9%). These four components constitute the complex aroma tested by the direct sensory method, and was largely recognized by the apple aroma test panel. Consequently, it was found that these components are the key factors in apple aroma. If the mechanism of formation of these components can be found, it could have a significant influence on consumers' acceptance of new varieties of apples.

• Bulletin of the Korean Chemical Society
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• v.18 no.7
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• pp.695-702
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• 1997

The objective of this work is to determine the sugar profiles in commercial fruit juices, and to obtain chemometric characteristics. Sugar compositions of fruit juices were determined by HPLC-RID and GC-FID via methoxymation and trimethylsilylation with BSTFA. The appearance of multiple peaks in GC analysis for carbohydrates was disadvantageous as described in earlier literatures. Fructose, glucose, and sucrose were major carbohydrates in most fruit juices. Glucose/fructose ratios obtained by GC were lower than those by HPLC. Orange juices are similar to pineapple juices in the sugar profiles. However, grape juices are characterized by its lower or no detectable sucrose content. In addition, it was also found that unsweeten juices contained considerable level of sucrose. Chemometric technique such as principal components analysis was applied to provide an overview of the distinguishability of fruit juices based on HPLC or GC data. Principal components plot showed that different fruit juices grouped into distinct cluster. Principal components analysis was very useful in fruit juices industry for many aspects such as pattern recognition, detection of adulterants, and quality evaluation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.458-461
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• 2003

Solid-phase microextraction (SPME) and gas chromatography/headspace techniques(HS) and flame ionization detection (GC/FID) have been combined for determination of very polar compounds in water, including the widely used gasoline oxygenates and by-products. A relatively simple extraction method using a CAR/PDMS(75${\mu}{\textrm}{m}$) SPME fiber was optimized for the routine analysis of gasoline oxygenates and by-products in groundwater and reagent water. A sodium chloride concentration of 25%(w/w) combined with an extraction time of 20 min provided the greatest sensitivity while maintaining analytical efficiency Replicate analyses in fortified reagent and groundwater spiked with microgram per liter concentrations of gasoline oxygenates and by-products indicate quantitative and reproducible recovery of these and related oxygenate compounds. Method dynamic range was 50$\mu\textrm{g}$ L-1 to 3000$\mu\textrm{g}$ L-1 for gasoline oxygenates and by-products.

• YAKHAK HOEJI
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• v.29 no.5
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• pp.260-267
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• 1985

A gas chromatography with flame ionization detection was developed to measure tranylcypromine in rat urine. The method involves extraction of the drug and the internal standard, phenylpropylamine from the urine using ethyl acetate and back extraction into 0.5N $H_{2}SO_{4}$. Following final extraction using dichloromethane, both the drug and the internal standard were converted to trifluoroacetyl derivatives and analyzed using a column of 3% SE-30 on 80/100 mesh Chromosorb W(HP). A calibration curve was constructed in the range of $5~50{\mu}g$tranylcypromine sulfate in 0.5ml urine and found to be linear. The detection limit was $2{\mu}g$. The tranylcypromine could be analyzed with the percent recovery of $100.81{\pm}8.13$ (SD) ina concentration range of $8-40{\mu}g$ in 0.5ml urine. When 0.4mmol/kg dose of the drug was administered through, an oral route, excretion percent of tranylcypromine in rat urine over 36hr was found to be $11.90{\pm}6.04$ (SD) for tranyleypromine sulfate and $2.23{\pm}0.63$ (SD) for benzyl trans-2-phenylcyclopropanecarbamate.