• Elastomers and Composites
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• 제51권1호
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• pp.63-67
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• 2016

Poly(ethylene-co-vinyl acetate) (EVA) was pyrolyzed to eliminate acetic acid of VA unit using off-line pyrolysis, and the deacetylated EVA was analyzed infrared spectroscopy (IR) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). EVA film for deacetylation was prepared by solution casting on aluminum foil and it was pyrolyzed at low temperature of $300^{\circ}C$ in the off-line pyrolysis apparatus. After deacetylation, carbon-carbon double bond (C=C) was formed by 1,2-elimination of the VA unit in the EVA backbone. Most of C=C bonds were trans-1,4-unit and 1,2-unit was also observed. Presence of the 1,2-unit in deacetylated EVA indicates that terminal or branch VA units exist in the raw EVA. Py-GC/MS chromatogram of deacetylated EVA displayed much smaller acetic acid and much more abundant other pyrolysis products than that of raw EVA, which means that the pyrolysis efficiency and separation condition were improved.

• 약학회지
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• 제47권5호
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• pp.266-270
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• 2003

We evaluated four commercially available methamphetamine immunoassays for their relative cross-reactivities of amphetamine analogues in human urine: Abbott TDx, Vitalab Selectra and on-site test kits (Accusign MET, SD bioline MET). High cross-reactivities were shown at designer's drugs such as methylenedioxyamphetamine (MDA), methylenedioxymethamphetamine (MDMA) and methylenedioxyethylamphetamine (MDEA) in all of the tested immunoassays. Methoxyphenamine, fenfluramine and phentermine were positive in TDx and Selectra, but were not positive in on-site test kits. Pseudoephedrine, norpseudoephedrine, ephedrine, norephedrine, MDMA, MDA, fenfluramine and phentermine were detected by gas chromatography/mass spectrometry(GC/MS) in false positive urines. Since the overall specificity of any of the devices was not 100％, we found it is important to confirm any positive screening test result, so we developed simultaneous determination of amphetamine analogues in urines. After alkalinization of the urine samples with 6-N NaOH, the analytes were extracted using ethyl acetate, derivatized with pentafluoropropyl anhydride (PFPA) prior at GC/MS analysis.

• 분석과학
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• 제17권6호
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• pp.527-531
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• 2004

Treatment with aqueous sodium hydroxide solution plays an important role to impart certain desirable properties - feel and luster on the surface of polyester fiber. In this process alkali wastewater contains disodium terephthalate, ethylene glycol (EG) and residual sodium hydroxide. In this paper we report a new method containing the pretreatments of derivatization with benzoyl chloride and solvent extraction using pentane. The calibration curve of EG determined by GC/MS-SIM shows a good linearity in the range of 0.1 to $25{\mu}g/mL$ having the standard deviation of ${\leq}8.7%$. The recovery and the detection limit of this method are 91.9-93.7% and $0.05{\mu}g/mL$ respectively.

• Bulletin of the Korean Chemical Society
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• 제23권10호
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• pp.1496-1511
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• 2002

• 보존과학회지
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• 제32권1호
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• pp.21-32
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• 2016

아교는 나전, 목가구, 단청 등 문화재에 접착제 및 교착제로 광범위하게 사용돼 온 전통재료이다. 아교의 분석과 확인은 주로 IR에 의한 작용기의 확인을 통해 이루어졌으나 몇 가지 물질이 섞여 있는 경우 밴드의 중복 등에 의해 명확하게 아교를 확인하는데 어려움이 있다. 열분해/GC/MS분석은 소량의 시료로 열분해 산물의 화학성분을 알 수 있어 아교 등 고분자 재료의 성분을 분석하는데 유용하다. 본 연구에서는 단청 시편에서 아교를 이 방법으로 확인하고자 하였다. 우선, 단청 채색에 사용되는 아교, 동유에 대한 열분해/GC/MS 분석을 실시하여 주요하면서 특징적인 열분해산물을 확인하였다. 또한, 뇌록을 칠한 단청시편을 제작하여 열충격 시험과 인공 풍화 시험 후에 분석을 했을 때 약화가 되긴 하였지만 아교의 특징적인 peak의 검출이 가능하였다. 이로부터, 단청과 같이 다양한 재료와 풍화상태로 구성된 문화재에서 아교의 검출이 열분해/GC/MS로 가능함을 확인하였다. 아울러, 단청 시편을 IR로 분석하여 IR과 열분해/GC/MS 분석 간에 아교 검출 능력을 비교하였다.

• 한국연초학회지
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• 제36권1호
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• pp.12-19
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• 2014

A matrix solid-phase dispersion (MSPD) method was developed for extracting and cleaning-up the selected agrochemicals in tobacco using gas chromatography-mass spectrometry with selected ion monitoring (GC/MS-SIM). Different parameters of the method were investigated and optimized, such as the type of solid-phase (alumina, $C_{18}$ and Florisil) and eluent (acetone, acetonitrile, ethylacetate and n-hexane). The best results were obtained using 0.5 g of tobacco sample, 1.0 g of $C_{18}$ as dispersant sorbent, 1.0 g of Florisil as clean-up sorbent and acetonitile saturated with n-hexane as eluting solvent. The method was validated using tobacco samples fortified with agrochemicals at their different concentration levels. This method gave good linearity for the selected agrochemicals of ranging from $0.01{\mu}g/mL$ to $0.1{\mu}g/mL$. Recoveries of the selected agrochemicals in tobacco were more than 80 % and reproducibilities were found to be better than 10 % RSD. Those results suggested that the analytical procedure including MSPD method in combining with GC/MS could be applicable to the rapid determination often the selected agrochemicals in tobacco.

• 한국식품과학회지
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• 제24권1호
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• pp.25-28
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• 1992

츄잉껌 품질향상의 일환으로 저장기간 및 여러 가지 상대습도하에서 츄잉껌 향기성분의 변화를 GC/MS로 분석하였다. 츄잉껌 향기성분을 시료전처리로 포집하고 tetradecane을 내부표준용액으로 이용해서 각 성분과의 peak area ratio로써 향기성분함량의 감소량을 측정한 결과 저장초기에는 53% R.H 저장분 보다 33, 75% R.H에서 감소속도가 빨라으나 그 이후는 차이가 별로 없었으며 16주 후에는 $45{\sim}49%$의 잔존량을 나타내었다.

• Natural Product Sciences
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• 제26권2호
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• pp.165-170
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• 2020

Carica papaya is a medicinal and fruit plant owing biological activities including antioxidant, antiviral, antibacterial and anticancer. The present study aims to investigate the acetyl (AChE) and butyryl (BChE) cholinesterase inhibitory potentials of C. papaya extracts as well as their chemical compositions. The chemical composition of the active extract was identified using a gas chromatography-mass spectrometry (GC-MS). Ellman enzyme inhibition assay showed that the alkaloid-enriched leaf extract of C. papaya possessed significant anti-BChE activity with an enzyme inhibition of 75.9%. GC-MS analysis showed that the alkaloid extract composed mainly the carpaine (64.9%) - a major papaya alkaloid, and some minor constituents such as aliphatic hydrocarbons, terpenes and phenolics. Molecular docking of carpaine revealed that this molecule formed hydrogen bond and hydrophobic interactions with choline binding site and acyl pocket. This study provides some preliminary findings on the potential use of C. papaya leaf as an herbal supplement for the prevention and treatment of Alzheimer's disease.

• Bulletin of the Korean Chemical Society
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• 제23권3호
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• pp.488-496
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• 2002

SPME techniques have proven to be very useful tools in the analysis of wide VOCs in the air. In this study, we estimated VOCs in ambient and workplace air using a Tedlar ba /SPME/GC/MS system. The calibration curve was set to be linear over the range of 1-30 ppbv. The detection limits ranged from 10 pptv to 0.93 ppbv for all VOCs. Reproducibility of TO-14 target gas mixtures by SPME/GC/MS averaged at 8.8 R.S.D (%). Air toxic VOCs (hazardous air pollutants, HAPs) containing a total of forty halohydrocarbons, aromatics, and haloaro-matic carbons could be analyzed with significant accuracy, detection limit and linearity at low ppbv level. Only reactive VOCs with low molecular weight, such as chloromethane, vinylchloride, ethylchloride and 1,2-dichloro-ethane, yielded relatively poor results using this technique. In ambient air samples, ten VOCs were identified and quantified after external calibration. VOC concentration in ambient and workplace air ranged from 0.04 to 1.85 ppbv. The overall process was successfully applied to identify and quantify VOCs in ambient/workplace air.

• 분석과학
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• 제15권3호
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• pp.221-228
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• 2002

MX [3-chloro-4(dichloromethyl)-5-hydroxy-2(5H)-furanone]는 수돗물의 소독을 위해 첨가한 염소와 수중의 유기물이 반응하여 생성되는 강력한 변이원성 물질이다. 본 논문에서는 GC/MS를 이용하여 유도체화 시약인 2% 황산-methanol, iso-propanol, sec-butanol, n-butanol을 이용하여 MX의 유도체화를 비교하였으며, 이온화 방법으로 EI 와 NCI를 비교한 결과, NCI 방법에서 검출 한계가 1.25 pg으로 EI 방법에서는 25 pg이였으며, 25~2500 pg 범위에서 직선성을 나타내었다.