• Journal of the Korean Chemical Society
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• v.42 no.6
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• pp.646-651
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• 1998

The molecular structure of sulfur compounds and the retention relationship are studied by gas chromatography. Analyzed sulfur compounds are, hydrogen sulfide, sulfur dioxide, carbon disulfide, ethyl mercaptan, dimethyl sulfide, iso-propyl mercaptan, normal propyl mercaptan, ethyl methyl sulfide, tert-butyl mercaptan, tetrahydrothiophene, thiophene, and 2-chlorothiophene. Multiple linear regression explains the retention relationship of molecular descriptors. In GC the temperature program is 30$^{\circ}C$ held for 10.5 min, and then increased to 150$^{\circ}C$ at a rate 15$^{\circ}C$/min. Predicted equation for relative retention time (RRT) using SAS program is as follows; $RRT=0.121bp+14.39dp-8.94dp^2+0.0741sqmw-35.78\; (N=8,\; R^2=0.989, \;Variance=0.175,\;F=66.21)$. RRTs are function of boiling point, the square root of molecular weight, molecular dipole moment, and boiling point effects mostly on RRT. The RRT is maximized at the molecular dipole moment of 0.805D, when using nonpolar columns. The planar and highly symmetric compounds are eluted slowly. The square, of correlation coefficient $(R^2)$ using SAS program, is 0.989, and the variance is 0.175 in training sets. For three sulfur compounds, the variance between observed RRTs and predicted RRTs is 0.432 in testing sets.

• Journal of Life Science
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• v.20 no.1
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• pp.60-65
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• 2010

Since organic sulfur compounds respond to GC/ECD sensitively, they interfere with quantitative separation of pesticides during residual pesticide analysis of Allium species. In this study, it was intended to develop a rapid and simple method for pesticide multi-residues analysis through clean-up and interferences by a solid-phase extraction (SPE). An SPE method employing silver nitrate impregnated Florosil cartridge was developed and evaluated for the elimination of sulfur compounds from the test solution of Allium species during pesticide residues analysis. The silver nitrate impregnated Florosil cartridge was prepared by efflux of 3 ml of 20% silver nitrate solution through Florosil cartridge (1 g packing, 6 ml tube). The extracts equivalent to 2, 4 6, and 10 g of each sample were loaded onto the cartridge and allowed to exude, and then the exudations were analyzed by GC/ECD. More than 95% of sulfur compounds were removed from the loaded extracts equivalent, up to 6 g in onion, 4 g in spring onion and 4 g in shallot, respectively. 40 pesticides were spiked in the Allium species and loaded onto the cartridge to determine the recoveries; from this, the recoveries of 34 pesticides were within 70~120%.

• Clean Technology
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• v.13 no.1 s.36
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• pp.64-71
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• 2007

The selection of a suitable adsorbent for removing organic sulfur compounds tetrahydrothiophene (THT) and t-butylmercaptan (TBM) from natural gas has been carried out. The saturation adsorption capacity for the sulfur compounds were determined by pulse adsorption method for a group of nanoporous materials, including Na-Y, Na-ZSM-5, Na,K-ET(A)S-10, Na-Mordenite, Na,K-Clinoptitolite, Ti/MCM-41, Ti/SBA-15 and amorphous titanosilicates. Among the materials tested, Na-Y and Na,K-ET(A)S-10 zeolites showed high adsorptive capacities for THT and TBM. The saturation capacity for THT on Na,K-ETS-10 was comparable with that on Na-Y zeolite, which is well known as an effective adsorbent. The capacity and adsorptivity for THT and TBM on Na,K-ETAS-10 were improved by an increase in crystallinity of Na,K-ETAS-10. An investigation of the competitive adsorption between THT and TBM from the breakthrough test using a simulated natural gas indicates that Na,K-ETS-10 selectively adsorbs THT. The breakthrough capacity for THT on Na,K-ETS-10 was 1.19 mmol/g. The results show that the high adsorption performance of Na.K-ETS-10 and Na,K-ETAS-10 is due to the highly exchanged cations in the zeolitic structure which exhibit the strong electrostatic interactions with organic sulfur compounds and their wide pore nature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.222-228
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• 1997

Toha-jeot, a traditional salt-fermented seafood in Korea, was purchased on the market in order to analyze the flavor compounds. Volatile flavor compounds in unfermented and fermented Toha-jeot were compared by vacuum simultaneous steam distillation-solvent extraction/gas chromatography/mass spectrometry. A total of 104 volatile flavor compounds were detected in both samples. Of these, 66 were positively identified, composed of aldehydes(14), ketones(8), alcohols(30), terpenes(20), sulfur-containing compounds(10), aromatic compounds (6), esters(12) and miscellaneous compounds(8). Levels of several other compounds such as aldehydes, terpenes, sulfur-containing compounds and esters decreased with fermentation time, whereas alcohols, ketone and aromatic compounds increased. Particularly, levels of alcohols in fermented Toha-jeot was 21 times higher than those of unfermented one. Major volatile flavor compounds in both samples were composed of terpenes, sulfur-containing compounds, esters and ethanol.

• Journal of the Korean Society of Food Culture
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• v.21 no.3
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• pp.319-324
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• 2006

Volatile compounds in low-temperature and long-term fermented Baechu kimchi were extracted by high vacuum sublimation(HVS), and then analyzed by gas chromatography/mass spectrometry(GC-MS). A total of 62 compounds, including 7 sulfur-containing compounds, 8 terpenes, 5 esters, 8 acids, 15 alcohols, 2 nitrites, 2 ketones, 11 aliphatic hydrocarbons and 4 miscellaneous compounds, were found in low-temperature and long-term fermented Baechu kimchi. Among them, acetic acid and butanoic acid were quantitatively dominant. Aroma-active compounds were also determined by gas chromatography/olfactometry(GC-O) using aroma extract dilution analysis(AEDA). A total of 16 aroma-active compounds were detected by GC-O. Butanoic acid was the most potent aroma-active compound with the highest FD factor($Log_3FD$) followed by linalool, acetic acid, 2-vinyl-4H-1,3-dithin and 3-methyl-1-butanol. The major aroma-active compounds, such as acetic acid and butanoic acid, were related to sour and rancid or notes.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.4
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• pp.319-326
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• 2014

Exhaust gas emitted as a result of the incomplete combustion of biomass in charcoal kilns includes odor compounds as well as other air pollutants such as particulate matters, sulfur and nitrogen oxides, and carbon monoxide. A number of offensive odor compounds affect quality of life. In this study, odor emissions were investigated from biomass burning in a pilot-scale charcoal kiln and a commercial-scale kiln. Complex odor from emission source reached up to 10,000 dilutions to threshold during the study period. Combustion fume was found to contain reduced sulfur compounds, aldehydes, and volatile organic compounds. Hydrogen sulfide and methyl mercaptan were the major odorants which highly contributed to the offensive odor.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.666-674
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• 2007

In this study, sampling and analysis was carried out for 13 compounds, in order to investigate the odorous compound emissions from landfill stacks and surrounding ambient air. These results revealed that concentration of hydrogen sulfide was $0.13{\sim}0.66\;ppb$ in the ambient air. Also, concentrations of hydrogen sulfide ($151{\sim}358\;ppm$) were the highest value in odorous sulfur compounds from landfill stacks. In case of VOC, toluene was obtained the highest out of volatile organic compounds. It was found that the concentrations of hydrogen sulfide near the landfill was higher than that inside city such as Seoul although it was located in a rural area. The result was due to the effect of hydrogen sulfide emitted from landfill stacks.

• Journal of Microbiology and Biotechnology
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• v.20 no.8
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• pp.1196-1203
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• 2010

In the present work, methanethiol and dimethyldisulfide were investigated as sulfur sources for methionine synthesis in Corynebacterium glutamicum. In silico pathway analysis predicted a high methionine yield for these reduced compounds, provided that they could be utilized. Wild-type cells were able to grow on both methanethiol and dimethyldisulfide as sole sulfur sources. Isotope labeling studies with mutant strains, exhibiting targeted modification of methionine biosynthesis, gave detailed insight into the underlying pathways involved in the assimilation of methanethiol and dimethyldisulfide. Both sulfur compounds are incorporated as an entire molecule, adding the terminal S-$CH_3$ group to O-acetylhomoserine. In this reaction, methionine is directly formed. MetY (O-acetylhomoserine sulfhydrylase) was identified as the enzyme catalyzing the reaction. The deletion of metY resulted in methionine auxotrophic strains grown on methanethiol or dimethyldisulfide as sole sulfur sources. Plasmid-based overexpression of metY in the ${\Delta}$metY background restored the capacity to grow on methanethiol or dimethyldisulfide as sole sulfur sources. In vitro studies with the C. glutamicum wild type revealed a relatively low activity of MetY for methanethiol (63 mU/mg) and dimethyldisulfide (61 mU/mg). Overexpression of metY increased the in vitro activity to 1,780 mU/mg and was beneficial for methionine production, since the intracellular methionine pool was increased 2-fold in the engineered strain. This positive effect was limited by a depletion of the metY substrate O-acetylhomoserine, suggesting a need for further metabolic engineering targets towards competitive production strains.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.555-562
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• 2010

For the rapid and reliable detection of toxic compounds in water, a novel toxicity detection methodology based on sulfur-oxidizing bacteria (SOB) has been developed. The methodology exploits the ability of SOB to oxidize elemental sulfur to sulfuric acid in the presence of oxygen. The reaction results in an increase in electrical conductivity (EC) and a decrease in pH. Using a synthetic stream water (EC=0.12 mS/cm and pH=7.2), the baseline steady-state EC and pH values were 0.5~1.2 mS/cm and ~2.5 over 7 days of testing at HRT 30 minutes. When nitrite compounds were added to the system, the effluent EC decreased and the pH increased due to the inhibition of the SOB. Optimum HRT was 30 min and this HRT could be decresed by using smaller sulfur particles.

• Microbiology and Biotechnology Letters
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• v.25 no.4
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• pp.354-358
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• 1997

Some sulfur coompounds dissimilation characteristcs of Thermococcus sp. DT1331 were studied. DT1331 had ether-like lipid compounds in addition to esters in the cell membrane. The specific growth rates of DT1331 decreased with increasing head spaces of the cultures. However, when the ratio of head space volume to medium volume was 5.60, the strain showed no growth. DT1331 showed vigo- rous growth with 1% or more elemental sulfur addition. Cystine could substitute elemental sulfur and DT1331 showed moderate growth with 0.1% or more cystine concentration. The specific growth rate and maximum cell concentration of Thermococcus sp. DT1331 in the presence of elemental sulfur were 0.80 hr$^{-1}$ and 2.0 x 10$^{8}$ cells/ml, respectively, while they were 0.67 hr$^{-1}$ and 1.1 x 10$^{8}$ cells/ml, respectively in the presence of cystine.