• Analytical Science and Technology
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• v.9 no.2
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• pp.123-133
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• 1996

The optimum conditions for the analysis of the difenoconazole fungicide on soil and crops were investigated and the residues of that in apple and soil were identified by using the gas chromatography. The extract with acetonitrile was separated with saturated NaCl and n-hexane solution after filtered, and concentrated. Obtained fungicide residues were transfered to the florisil column and eluted with acetone and n-hexane mixed solution for the analysis by GLC(ECD). From the standard addition experiments with 0.20 and 1.0ppm, the average recoveries were 86~92% and the detection limit was 0.01 ppm. It seems to be safely used when difenoconazole is treated three times until 15 days before harvest of apple. In this case residual amounts of difenoconazole in apple was from 0.037ppm to 0.044ppm. The soil samples extracted with methanol and ammonium hydroxide mixed solution were partitioned with dichloromethane and saturated sodium chloride solution. The organic phase was concentrated and redissolved with toluene and analyzed with GLC(FID) after cleaned with Sep-Pak column. From the standard addition experiments with 0.10, 0.50 and 1.0ppm, the average recoveries were 101.2~103.7% and the detection limit was 0.025ppm.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2002.11b
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• pp.27-27
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• 2002

식용피(Echinochloa crus-galli var. formosensis Ohwi.) 유묘에 대한 생육저해 정도를 지표로 하여 경북 북부지방에 자생하는 10여종의 야생식물의 부위별 MeOH 추출물을 조사한 결과, 1,000 ppm에서 가죽나무(가지)및 할미꽃(경엽부)은 식용피 유묘의 뿌리의 생육을 약 60∼80% 억제시키는 것으로 나타났다. 식물생장억제활성이 나타난 상기 2종에 대해 각종 크로마토그래피법을 적용하여 활성의 본체를 분리ㆍ정제한 결과, 가죽나무 가지 및 할미꽂 경엽부로부터 500 ppm에서 식용피 유묘 뿌리의 생육을 각각 96%와 73% 억제하는 활성분획들이 획득되었으며, GC/MS 분석을 통해 이들 활성분획으로부터 수종의 식물생장억제활성물질들이 확인되었다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.195-198
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• 2005

A solid-phase microextraction and gas chromatography-mass spectrometry for the extraction and analysis of methyl-tert-butyl ether has been described. methyl-tert-butyl ether was extracted from aqueous solution using SPME fiber coated polydimethylsiloxane and analysed by GC-MS with capillary column. Extraction parameters and chromatographic separation conditions were optimized. The applied method represented good analytical performance in terms of precision (3-8%, RSD) and accuracy(93-102%, mean recovery) with a method detection limit of 0.03 ppb.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.3
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• pp.185-190
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• 1988

Soybean lipoxyeenase isozymes were isolated from acetone-defatted soybean seeds(Glycine max [L.] Merr. variety AmSoy) by ammonium sulfate fractionation, eel filtration, and ion exchange chromatoeraphy. The final preparation of lipoxygenase-1 and -2 obtained was 19- and 32-fold purified, respectively, to the crude extract. But a considerable loss of total enzyme activity occurred during purification. On 7% polyacrylamide gel electrophosis at pH 9.0, employing lipoxigenase specific staining technique, lipoxyeenase-1, -2, and -3 showed distinctive Rf values of 0.38, 0.29, and 0.33, respectively.

• Analytical Science and Technology
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• v.17 no.1
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• pp.85-89
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• 2004

Fragrance components of lilac (Syringa vulgaris) blossom have been characterized in this paper. The accurate characterization of fragrances collected from lilac blossom was carried out by solid-phase trapping-solvent extraction and gas chromatography-ion trap mass spectrometry. According to lilac species, the chemical compositions were significantly different. Benzaldehyde, phenylacetaldehyde, and ${\alpha}$-farnesene were found as the predominant component of white lilac blossom whereas benzaldehyde, ${\alpha}$-pinene, and ocimene were those of pale purple lilac. The enantiomeric analysis of ${\alpha}$-pinene in lilac blossom was found in the form of ( ).

• Journal of Korean Society of Environmental Engineers
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• v.37 no.5
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• pp.262-268
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• 2015

This study established an analytical method to simultaneously determine six organophosphorous pesticides [methyldemetone-S, diazinon, fenitrothion, parathion, phentoate, and O-ethyl O-(4-nitrophenyl) phenylphosphonothioate (EPN)] and carbaryl in water using a gas chromatography/mass spectrometry (GC/MS) system coupled with on-line micro extraction by packed sorbent (MEPS) and programmed temperature vaporizer (PTV) injector. Polystyrene divinylbenzene (PDVB) was used as a sorbent of MEPS. The effects of elution solvents, pH, elution volume and draw-eject cycles of samples on sample pretreatment process were investigated. Also, quality assurance and quality control (QA/QC) and the recovery of the pesticides in environmental samples were evaluated. The elution was performed using $30{\mu}L$ of a mixed solvent (acetone : dichloromethane = 80 : 20 (v/v)). Sample pretreatment processes were optimized with seven cycles of draw-eject of sample (1 mL) spiking an internal standard and sulfuric acid. At lower pH, the analytical sensitivity of diazinon decreased, but that of carbaryl increased. The method detection limit and the limit of quantification for this method were 0.02~0.18 and $0.08{\sim}0.59{\mu}g/L$, respectively. The method precision and accuracy were 1.5~11.5% and 83.3~129.8%, respectively, at concentrations of $0.5{\sim}5.0{\mu}g/L$. The recovery rates for all the pesticides except carbaryl in various environmental samples ranged 75.7~129.3%. The recovery rate of carbaryl in effluent sample was over 200% whereas carbaryl in drinking water, groundwater, and river water were in the acceptable range.

• Analytical Science and Technology
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• v.17 no.4
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• pp.322-336
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• 2004

The improved derivatization technique of tamoxifen metabolite in human urine is described for the acylation method that they are substituted by derivatization reagent like acyl anhydride for use of gas chromatography/mass spectrometry. The hydroxyl group of tamoxifen metabolite was derivatized by trifluoroacetic anhydride (TFAA), pentafluoroacetic anhydride (PFPA) and heptaflorobutylic anhydride (HFBA). It was investigated to the gas chromatography/mass spectrometry (GC/MS) technique use negative ion chemical ionization (NCI), positive ion chemical ionization (PCI) and electron impact (EI). In acylation of the metabolites of tamoxifen, the effective reaction temperature and time were shown to be at $50^{\circ}C$ for 30 min. The 4-hydroxytamoxifen, which is known to major metabolite of tamoxifen, was not detected in human urine, whileas the hydroxymethoxytamoxifen was detected. We thought that this result was from the single dose of tamoxifen.

• Economic and Environmental Geology
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• v.40 no.1 s.182
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• pp.129-140
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• 2007

CFC(CFC-12, CFC-11 and CFC-113) analytical system for air and water was constructed using a customized purge and trap extraction device and a gas chromatograph with an electron capture detector. Sampling methods of air and water for CFCs were also established. The analytical system was experimentally optimized to result in reproducibilities of triplicates less than 2% for current air samples and less than 5% for groundwater samples with CFC-12 concentration of 160 to 180 pg/kg, and verified with respect to the CFC system in USGS, which showed analytical results were in agreement within 10%. CFCs in air were monitored at three sites over 19-month period in the central part of South Korea, and the result indicates no significant local sources of CFCs in those areas. For groundwater in Jeju Island, CFCs were measured over a year with a two-month interval. The time-series data showed seasonal fluctuations which could be interpreted by the effect of recharge pulse derived from large amount of rainfall during monsoon period with a few month delay, which indicates high permeability of basaltic rocks in Jeju Island.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.235-238
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• 2012

본 연구는 Glycine max (L.) Merr.의 태좌부위를 순수 분리하여 callus 세포를 유도하고 2차 대사산물인 isoflavone류에 속하는 daidzein의 생산성을 증진시킬 수 있는 방법을 찾는데 있다. 배양된 callus를 다양한 용매를 사용하여 추출하고, 추출물을 액체 크로마토그래피로 분석해 daidzein 함량의 차이를 확인하였다. 또한 핵자기공명분광법으로 50% 에탄올 추출물 내에 daidzein이 함유되어 있음을 증명하였다.

• Analytical Science and Technology
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• v.16 no.6
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• pp.458-465
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• 2003

The HS (headspace)-SPME (Solid phase microextraction) as rapid and simple method was performed for the determination of volatile fatty acids (VFAs) from the aqueous samples. In-fiber derivatization of VFAs with 1-Pyrenyldiazomethane (PDAM) was applied to improve their sensitivity of detection. In SPME procedure, typical parameters such as effects of solution pH, and salting out reagent and ultrasonication were investigated to improve the extraction efficiency. Based on the developed method, VFAs in wastewater samples were determined by gas chromatography / mass spectrometry-selected ion monitoring (GC/MS-SIM) mode.