• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.177-183
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• 2013

Bacterial blight, an important and potentially destructive bacterial disease in rice caused by Xanthomonas oryzae pv. oryzae (Xoo), has recently developed resistance to the available antibiotics. In this study, mass spectrometry (MS)-based metabolite profiling and multivariate analysis were employed to investigate the correlation between timedependent metabolite changes and antimicrobial activities against Xoo over the course of Phomopsis longicolla S1B4 fermentation. Metabolites were clearly differentiated based on fermentation time into phase 1 (days 4-8) and phase 2 (days 10-20) in the principal component analysis (PCA) plot. The multivariate statistical analysis showed that the metabolites contributing significantly for phases 1 and 2 were deacetylphomoxanthone B, monodeacetylphomoxanthone B, fusaristatin A, and dicerandrols A, B, and C as identified by liquid chromatography-mass spectrometry (LC-MS), and dimethylglycine, isobutyric acid, pyruvic acid, ribofuranose, galactofuranose, fructose, arabinose, hexitol, myristic acid, and propylstearic acid were identified by gas chromatography-mass spectrometry (GC-MS)-based metabolite profiling. The most significantly different secondary metabolites, especially deacetylphomoxanthone B, monodeacetylphomoxanthone B, and dicerandrol A, B and C, were positively correlated with antibacterial activity against Xoo during fermentation.

• 통합자연과학논문집
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• 제11권3호
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• pp.161-164
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• 2018

Over the past decade, mass spectrometry-based metabolomics, especially two dimensional gas chromatography mass spectrometry (GCxGC/TOF-MS), has become a key analytical tool for metabolomics data because of its sensitivity and ability to analyze complex biological or biochemical sample. However, the need to reduce variations within/between experiments has been reported and methodological developments to overcome such problem has long been a critical issue. Along with methodological developments, developing reasonable performance measure has also been studied. Following four numerical measures have been typically used for comparison: sensitivity, specificity, receiver operating characteristic (ROC) curves, and positive predictive value (PPV). However, more recently, such measures are replaced with F1 score in many fields including metabolomics area without any carefulness of its validity. Thus, we want to investigate the validity of F1 score on two examples, with the goal of raising the awareness in choosing appropriate performance comparison measure. We noticed that F1 score itself, as a performance measure, was not good enough. Accordingly, we suggest that F1 score be supplemented with other performance measure such as specificity to improve its validity.

• 분석과학
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• 제15권5호
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• pp.445-450
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• 2002

해수에 함유되어 있는 요오드화합물의 총량을 휘발성 유기물로 유도체화 후 측정하는 방법을 확립하였다. 이 방법은 요오드 음이온은 요오드로 산화시킨 후 2,6-dimethylphenol과 반응하여 4-iodo-2,6-dimethylphenol로 전환시켜 ethylether로 1단계 추출 후 gas chromatography-mass spectrometry (selected ion monitoring)로 측정하는 것으로 구성되어 있다. Iodate는 ascorbic acid 와 acetic acid로 요오드 음이온으로 환원시킨 후 요오드 음이온 측정법과 동일하게 수행하였다. 이 방법은 검출한계가 해수에서 0.1 ng/ml이었으며 검량선은 0.9997의 좋은 상관계수값을 보였다. 이 방법은 또한 재현성이 우수하고 간단하여 해수에 인체의 필수원소인 요오드를 낮은 농도까지 분석하는데 유용하게 사용될 수 있다고 사료된다.

• 한국환경성돌연변이발암원학회지
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• 제21권2호
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• pp.122-127
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• 2001

4-tert-octylphenol (OP) is a surfactant additive widely used in the manufacture of a variety of detergents and plastic products. Also, OP is known to have estrogenic activity by interacting with development and functions of endocrine system. This study was carried out to obtain toxicokinetic parameters of OP in male Sprague-Dawley rats. Male rats were administered OP, by either single oral (gavage) applications of 50, 100 or 200 mg/kg body weight. or a single intravenous injections of 1, 5 or 10 mg/kg body weight. Blood samples taken at several time intervals after administration were obtained from the femoral artery. Analysis of blood samples for OP was performed by gas chromatography mass spectrometry (GC/MS). The detection limit of OP was 1.9 ng/$m\ell$ at SIM (selected ion monitoring) mode of GC/MS. Calibration curve for analysis of the concentrations of OP in plasma was (OP/butylphenol peak area ratio) = 0.0294 $\times$ (plasma cone.) + 0.028 ($r^2$= 0.9991). The OP plasma concentration was 3921 ng/$m\ell$ immediately after single intravenous application, decreased rapidly within 45 min, and was detectable at low concentration up to 6 hr after application. When administered orally in rats (50, 100 and 200 mg/kg), OP was detected in the blood early after gavage administration, indicating the rapid initial uptake from gastrointestinal tract, with Tmax obtained from 0.67~0.83 hr. Using the AUC (area under the curve) of plasma concentration vs. time, low oral bioavailabilities of 1.2, 5.0 and 5.3% were calculated for the 50, 100 and 200 mg/kg groups, respectively.

• 한국포장학회지
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• 제15권3호
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• pp.93-98
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• 2009

Migration levels of plasticizers, di-n-butyl phthalate (DBP), benzyl-butyl phthalate (BBP), di-n-octyl phthalate(DNOP), di-iso-decyl phthalate (DIDP) and di-iso-nonyl phthalate (DINP), di-(2-ethylhexyl) adipate (DEHA), from 46 poly(vinyl chloride) (PVC) wrap films and 54 PVC gaskets into food simulants were determined using gas chromatography/mass spectrometry (GC/MS). The method was validated with limit of detection (LOD) of $0.01{\sim}0.02\;{\mu}g/mL$ for DBP, BBP, DNOP and DEHA, and $2\;{\mu}g/mL$ for DIDP and DINP. The linearity were found to be > 0.99 for all the compounds in concentration range of $0.1{\sim}81.4\;{\mu}g/mL$, and overall recoveries were ranged from 90.4 ~ 99.6%. DBP, BBP, DNOP, DEHA, DIDP and DINP were not detected in food simulants, except 1 wrap sample from which 0.28 and $0.99\;{\mu}g/mL$ of DEHA were detected respectively when tested with 20% ethanol and n-heptane as food simulants. These values were below the regulatory limitation in European Union (EU).

• 분석과학
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• 제14권1호
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• pp.44-49
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• 2001

GC-MS와 연결된 $85{\mu}m$ 폴리 아크릴레이트 fiber의 SPME가 풍선 시료 중에 포함된 가소제를 분석하는데 사용되었다. 풍선은 IR 분광법에 의해 폴리이소프렌으로 만들어진 것으로 판명되었다. 한시간 동안 아세톤이 첨가된 물 용매에서 추출된 풍선의 가소제는 9종류의 가소제가 포함된 외부표준법에 의해 정량 하였다. 정량법은 $0.25-25{\mu}g/g$의 농도범위에서 표준 가소제들에 대하여 유효화 과정을 거쳤으며, 검출한계는 가소제에 따라 $0.11-0.38{\mu}g/g$이었고, 이러한 정량법에 의한 재현성의 RSD는 3.7-14.2%이었다. 이들 풍선 중에는 우려할만한 수준의 환경호르몬성 가소제가 검출되는 제품도 포함되어 있어 이들에 대한 규제의 필요성이 있다.

• 보존과학회지
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• 제35권4호
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• pp.295-307
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• 2019

In the process of the conservation treatment of the glass eyes of the stone standing Maitreya of Daejosa temple, Buyeo (Treasure No. 217), a blackish material, expected to be the adhesive for fixing the glass eyes, was collected and analyzed. Infrared spectroscopy and pyrolysis/gas chromatography/mass spectrometry (pyrolysis/GC/MS) were employed to identify the organic material in the sample. The IR analysis revealed the presence of materials such as apatite or bone black. The pyrogram of the sample was similar to that of Asian lacquer, among traditional adhesives. In particular, the pyrolysis/GC/MS analysis with online methylation detected 1,2-dimethoxy-3-pentadecylbenzene, methyl 7-(2,3- dimethoxyphenyl) heptanoate, and methyl 8-(2,3-dimethoxyphenyl)octanoate. These are known to be the pyrolysis products of catechol and its oxidation product, which indicated the presence of Asian lacquer in the sample. X-ray diffraction, X-ray fluorescence, and thermal gravimetry analysis showed that the sample contained ca. 60% inorganic substances, including apatite. Radiocarbon dating of the sample suggested that the blackish material was applied between the late 13^th and early 15^th century, revealing some discrepancy with the art-historical manufacturing time of the Maitreya. From the above analysis, it was concluded that Asian lacquer and bone ash were used to attach the glass eyes by forming a thick blackish lacquer layer.

• 분석과학
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• 제14권5호
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• pp.392-399
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• 2001

생물시료에 존재하는 휘발성 유기화합물 중 n-butylbenzene과 1,2-dibromo-3-chloropropane (DBCP)를 기체크로마토그래피/질량분석기-선택이온검색법에 의해 수행하였다. 시료 중 휘발성 유기화합물은 $100{\mu}m$ polydimethyl siloxane (PDMS) fiber를 사용하여 headspace solid phase microextractio (SPME) 및 purge & trap 방법에 의해 추출 및 비교하였다. SPME에 의한 회수율은 n-butylbenzene의 경우 85.8%, DBCP의 경우 92.4%로 나타났고 검출한계는 각각 $0.15{\mu}g/kg$, $0.05{\mu}g/kg$로 나타났다. 반면, purge & trap의 경우 회수율은 n-butylbenzene의 경우 115.2%, DBCP의 경우는 80.9%로 나타났고 검출한계는 각각 $0.04{\mu}g/kg$ 및 $0.70{\mu}g/kg$로 나타나 두 방법에 있어 국내에서 규제하는 검출한계측면에서 큰 차이는 없었다.

• 공업화학
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• 제29권2호
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• pp.248-251
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• 2018

고정층 반응기와 파이롤라이저-가스크로마토그래피/질량분석기를 이용하여 커피 잔류물이 함유된 폐종이컵의 열분해 및 촉매 열분해를 진행하였다. 커피 잔류물이 함유된 종이컵의 무촉매 열분해에서는 많은 양의 오일이 가스 및 촤와 함께 형성되었다. HZSM-5와 HY 촉매의 사용에 따른 추가적인 분해 반응에 의해 오일의 양은 줄고 가스의 양은 증가하였다. HZSM-5와 HY의 산촉매 특성 때문에 커피 잔류물이 함유된 종이컵의 촉매 파이롤라이저-가스크로마토그래피/질량분석기 분석은 생성오일 중 방향족 화합물의 선택도를 증가시켰다. HY보다 강한 산세기와 중간 기공을 가진 HZSM-5의 특성으로 인해, HZSM-5상에서 커피 잔류물이 함유된 종이컵을 촉매 열분해한 경우 HY를 사용한 경우보다 휠씬 더 많은 양의 방향족 화합물이 생성되었다.

• 분석과학
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• 제9권4호
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• pp.392-398
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• 1996

광주천 유역내에 분포된 8개 업종 26개 배출원의 원폐수로부터 인간에게 유해한 11개의 유기화학물질 tetrachloroethylene, ethyl benzene, p-xylene, o-xylene, isopropyl benzene, n-propyl benzene, 1,2,4-trimethyl benzene, 1,3,5-trimethyl benzene, p-isopropyl toluene, see-butyl benzene, naphthalene을 액체-액체 추출법으로 분리하였다. 추출물 중 각 화합물들의 구조는 기체 크로마토그래피/질량분석계(GC/MS)를 사용하여 확인하였고, 표준시료와 비교함으로써 밝혔다.