• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.547-552
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• 2007

This study examined the thermal reactions of 2,4-dibromophenol (diBP), 2,6-diBP and 2,4,6-triBP. The products obtained under pyrolytic conditions were analyzed by gas chromatography/mass spectrometry (GC/MS). 2,7-dibromodibenzo-p-dioxin (diBDD) was the major compound produced from the thermal reaction of 2,4-diBP. In addition, monoBDD and triBDDs were obtained through a process of debromination and bromination, respectively. The pyrolysis of 2,6-diBP and 2,4,6-triBP produced two major brominated dioxin isomers through direct condensation and a Smiles rearrangement. The two ortho-Brs in 2,6-diBP and 2,4,6-triBP mainly led to the production of dioxins, whereas in addition to 2,7-diBDD, 2,4-diBP produced two furans as minor products, 2,8-dibromodibenzofuran (diBDF) and 2,4,8-triBDF, through the intermediate dihydroxybiphenyl (DOHB). The maximum yield of the major dioxins was obtained at 400 oC, and decomposition by debromination at 500 oC resulted in less substituted bromodioxins.

• 한국물환경학회지
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• 제28권5호
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• pp.669-675
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• 2012

Recently, there have been active researches regarding endocrine-disrupting chemicals (EDCs). In this study, fifteen small freshwater streams in Cholla-namdo province, South Korea were investigated with respect to the concentration of the endocrine disruptors - Bisphenol A (BPA), styrene monomer (SM), styrene dimer (SD), and styrene trimer (ST) by gas chromatography-mass spectrometry (GC-MS). Measured concentration of the target compounds in the sampled water ranged from

• Food Science and Biotechnology
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• 제15권1호
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• pp.112-116
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• 2006

Levels of ethyl carbamate, by-product produced naturally during fermentation, in Korean alcoholic beverages were determined by Gas Chromatography/mass spectrometry/selected ion mode (GC/MS/SIM), and their daily intake by Korean adult group was estimated. In GC/MS/SIM analysis 0.8-10.1, 0.5-0.8, 0.4-0.9, 3.5-689.9, 8.4-30.3, 13.9-30.0, and 1.7-11.7 ppb of ethyl carbamate were detected in soju, beer, takju, fruit wine, cheongju, whiskey, and grape wine, respectively. Maximum daily exposure of ethyl carbamate through alcoholic beverage consumption was 7.41 ng/kg body weight/day for average Korean male, with one soju brand and two fruit wine brands showing high ethyl carbamate level.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3603-3609
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• 2011

A novel sampling method of the headspace poly(dimethylsiloxane) (PDMS) mini-disk extraction (HS-PDE) was developed, optimized, validated and applied for the GC/MS analysis of spices flavors. A prototype PDMS mini-disk (8 mm outer diameter, 0.157 mm thickness, 9.4 mg weight) has been designed and fabricated as a sorption device. The technique uses a small PDMS mini-disk and very small volume of organic solvent and less sample size than the solvent extraction. This new HS-PDE method is very simple to use, inexpensive, rapid, requires less labor. Linearities of calibration curves for ${\alpha}$-pinene, ${\beta}$-pinene, limonene and ${\gamma}$-terpinene by HS-PDE combined with GC/MS were excellent having $r^2$ values greater than 0.99 at the dynamic range of 6.06~3500 ng/mL. The limit of detection (LOD) and the limit of quantitation (LOQ) showed very low values. This method exhibited good precision and accuracy. The overall extraction efficiency of this method was evaluated by using partition coefficients ($K_p$) and concentration factors (CF) for several characteristic components from nutmeg and mace. Partition coefficients were in the range from $2.04{\times}10^4$ to $4.42{\times}10^5$, while CF values were 0.88-15.03. HS-PDE was applied successfully for the analysis of flavors compositions from nutmeg, mace and cumin. The HS-PDE method is a very promising sampling technique for the characterization of volatile flavors.

• Journal of Ecology and Environment
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• 제29권4호
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• pp.381-387
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• 2006

We analyzed the total yields and composition of essential oils in leaf extracts of Nepeta cataria by Gas Chromatography Mass Spectrometry (GC-MS). Thirty-six compounds representing 97.0% of total oil were detected. The major constituents of essential oils in Nepeta cataria were nepetalactone (90.9%), unidentified compound (Retention time 17.35; 1.82%), 1,8-cineol (1.49%), ${\beta}-caryophyllene$ (1.12%), and ${\beta}-pinene$ (1.078%). The volatile compounds in leaf extracts of N. cataria concentrated to nepetalactone ($88.83{\sim}93.33%$) remarkably. In the essential oil of N. cataria cis,trans-nepetalactone ($30.2{\sim}37.8%$) and cis,cis-nepetalactone ($31.5{\sim}37.0%$) were found as the main constituents. The effects of essential oil of N. cataria on the growth of six microorganisms (Bacillus cereus, B. subtilis, B. amyloliquefaciens, Escherichia coli, Staphylococcus aureus subsp. aureus, and Pseudomonas aeruginosa) were investigated. The essential oil of N. cataria had strong inhibitory effect on the growth of three fungal species (Bacillus cereus, B. subtilis, and B. amyloliquefaciens). The essential oil from N. cataria was found to have a low antimicrobial activity against Staphylococcus aureus subsp. aureus, while no activity were found against Escherichia coli and Pseudomonas aeruginosa. Results indicate the significant antimicrobial effect, which may be depended on the yield of nepetalactone.

• Food Science and Biotechnology
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• 제15권3호
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• pp.341-346
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• 2006

This study was performed to examine the effects of ${\gamma}$-irradiation on the volatile flavor compounds of dried leeks (Alliums tuberosum R.). Volatile compounds of dried leeks were extracted using simultaneous steam distillation and extraction (SDE), and analyzed by gas chromatography/mass spectrometry (GC/MS). Forty-one, 51, 45, and 42 compounds were tentatively identified in control, 1, 3, and 10 kGy irradiated samples, respectively. The constituents of flavor compounds in irradiated dried leeks were similar to non-irradiated samples. However, the intensities of the peaks were clearly different between them. Sulfur-containing compounds were detected as dominant compounds in all samples and their amounts decreased after ${\gamma}$-irradiation. ${\gamma}$-Irradiation reduced the total concentration of volatile compounds from leeks by 23.19, 15.09, and 30.23% at 1, 3, and 10 kGy doses, respectively.

• Journal of Microbiology and Biotechnology
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• 제28권12호
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• pp.1971-1981
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• 2018

In this study, we investigated the altered enzymatic activities and metabolite profiles of koji fermented using varying permutations of Aspergillus oryzae and/or Bacillus amyloliquefaciens. Notably, the protease and ${\beta}$-glucosidase activities were manifold increased in co-inoculated (CO) koji samples (co-inoculation of A. oryzae and B. amyloliquefaciens). Furthermore, gas chromatography-mass spectrometry (GC-MS)-based metabolite profiling indicates that levels of amino acids, organic acids, sugars, sugar alcohols, fatty acids, nucleosides, and vitamins were distinctly higher in CO, SA (sequential inoculation of A. oryzae, followed by B. amyloliquefaciens), and SB (sequential inoculation of B. amyloliquefaciens, followed by A. oryzae). The multivariate principal component analysis (PCA) plot based on GC-MS datasets indicated a clustered pattern for MA and MB (koji samples inoculated either with A. oryzae or B. amyloliquefaciens) across PC2 (20.0%). In contrast, the CO, SA, and SB metabolite profiles displayed segregated patterns across PLS1 (22.2%) and PLS2 (21.1%) in the partial least-square discriminant analysis (PLS-DA) model. Intriguingly, the observed disparity in the levels of primary metabolites was engendered largely by higher relative levels of sugars and sugar alcohols in MA, SA, and CO koji samples, which was commensurate with the relative amylase activities in respective samples. Collectively, the present study emphasizes the utility of integrated biochemical and metabolomic approaches for achieving the optimal permutation of fermentative inocula for industrial koji preparation.

• 한국식품영양학회지
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• 제31권6호
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• pp.890-896
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• 2018

The aim of this study was to determine volatile flavor compounds in Shingo pear juice. Volatile flavor compounds were analyzed using solid-phase micro-extraction (SPME) - gas chromatography-mass spectrometry (GC-MS). The effect of inorganic salts solution on the extraction ability of the SPME fiber was treated by adding saturated $CaCl_2$ solution at the ratio of 1:20 (v/v) after 0, 60, 120 min of preparing pear juice, respectively. As a result, a total of 22 volatile compounds were identified in Shingo pear juice. Ethyl acetate was found to be the most abundant volatile compound ($13.36{\sim}19.61{\mu}g/kg$), followed in order by hexanal, ethyl hexanoate, ethyl 3-(methylthio)-2-propenoate, ethyl octanoate and 2-hexenal. Total contents of volatile flavor compounds were $31.07{\mu}g/kg$ (control), $40.93{\mu}g/kg$ (0 min), $27.62{\mu}g/kg$ (60 min) and $26.32{\mu}g/kg$ (120 min). This result indicated that the addition of saline solutions could inhibit the enzymatic reaction of volatile flavor compounds effectively when treated as soon as juice preparation.

• 한국산업보건학회지
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• 제32권4호
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• pp.371-380
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• 2022

Objectives: To ensure that employers handling petroleum compounds understand whether petroleum-based UVCB (unknown or variable composition, complex reaction products, or biological materials) substances contain hazardous substances and comply with the Occupational Safety and Health Act, petroleum-based UVCB substances were analyzed and the results from samples were compared with MSDS (Material Safety Data Sheet) contents. Methods: Twenty-one petroleum samples were analyzed using GC-MS (Gas Chromatography-Mass Spectrometry), targeting ten volatile organic compounds regulated by the Occupational Safety and Health Act. Results: The target chemicals were detected in 13 out of 21 samples. All 13 samples were in the naphtha (low boiling point naphthas (gasolines)) group. There were also naphtha group samples containing 2% benzene. Some naphtha samples used as solvents contained about 1% benzene. Conclusions: This study shows that naphtha group petroleum substances contain hazardous chemicals in many cases. In particular, if benzene, n-hexane, and toluene with low occupational exposure limits are contained above the limit concentration. Such information should be delivered in the article on MSDS legal regulations.

• Journal of the Korean Wood Science and Technology
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• 제52권1호
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• pp.31-46
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• 2024

Subterranean termite attacks on cajuput (Melaleuca cajuputi) seedling roots were widespread in several of Java's Perum Perhutani Forest Management Units. This attack was suspected to be related to the chemical components of the cajunput seedling roots. This study was conducted to determine the bioactivity of cajuput seedling root extract as an attractant for the subterranean termite Coptotermes curvignathus Holmgren (Isoptera: Rhinotermitidae). The extraction process was performed according to ASTM D1108-96, and the extract was characterized using gas chromatography-mass spectrometry (GC-MS). Bioactivity testing of the extracts was carried out using attractiveness and no-choice feeding bioassays. The results showed that the average root extraction yield from cajunput seedlings was 4.94%. The attractiveness of the extract solutions at concentrations of 0.50%, 0.75%, and 1.00% were 45.33%, 62.00%, and 74.67%, respectively. The mortality rate of C. curvignathus termites ranged from 9.63% to 24.44%. Cajuput seedling root extract's lethal concentration 50 was 2.45% (non-toxic). GC-MS analysis showed that the extract contained linoleic acid, which has the potential to attract insects.