• Fisheries and Aquatic Sciences
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• v.17 no.1
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• pp.67-73
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• 2014

The oil in mackerel muscle was extracted using an environment friendly solvent, supercritical carbon dioxide (SC-$CO_2$) at a semibatch flow extraction process and an n-hexane. The SC-$CO_2$ was maintained at a temperature of $45^{\circ}C$ under pressures ranging from 15 to 25 MPa. The flow rate of $CO_2$ (27 g/min) was constant during the entire 2 h extraction period. The fatty acid composition of the oil was analyzed using gas chromatography (GC). Significant concentrations of eicosapentaenoic acid (EPA) acid and docosahexaenoic acid (DHA) acid were present in the SC-$CO_2$ extracted oil. The oil extracted using SC-$CO_2$ exhibited increased stability compared with n-haxane extracted oil. Particles of mackerel oil together with the biodegradable polymer, polyethylene glycol (PEG) were formed using a gas saturated solution process (PGSS) with SC-$CO_2$ in a thermostatted stirred vessel. Different temperatures ($45-55^{\circ}C$), pressures (15-25 MPa) and a nozzle size $400{\mu}m$ were used for PGSS with a 1 h reaction time. The stability of mackerel oil in the particles did not changed significantly.

• Journal of Environmental Health Sciences
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• v.39 no.6
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• pp.483-491
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• 2013

Objectives: Electronic cigarettes are battery powered devices that convert a nicotine-containing liquid into an inhalable vapor. The device aerosolizes nicotine so that it is readily entrained into the respiratory tract, from where it enters the bloodstream. Information on the safety of E-cigarettes is required. Methods: Seventeen articles on studies analyzing toxic substances in the liquid and gas phases of electronic cigarettes were reviewed. Results: Tobacco-specific nitrosamines, bis(2-ethylhexyl) phthalate, formaldehyde and acetaldehyde, known to be carcinogenic agents in humans or animals, were detected in the liquid and gas phases. In addition, diethyl phthalate, acetone, ethanol, cresol, xylene, propylene, styrene, triethylene glycol, tetraethylene glycol, pentaethylene glycol cis-3-hexen-1-ol, methyl cinnamate and undecane were identified in the liquid and gas phases of E-cigarettes. Propylene glycol, glycerin, 1-methoxy-2-propanol, 1-hydroxy-2- propanone, acetic acid, 1-menthone, 2,3-butanediol, menthol, carvone, maple lactone, benzyl alcohol, 2-methyl-2-pentanoic acid, ethyl mantel, ethyl cinnamate, myosamine, benzoic acid, 2,3-bipyridine, cotinine, hexadecanoic acid, and 1'1-oxybis-2-propanol were detected in the vapors of E-cigarettes. Conclusion: The hazardous compounds identified in the liquid and gas phases of E-cigarettes should be controlled for the lowest concentrations in the raw materials and production procedures.

• Analytical Science and Technology
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• v.15 no.5
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• pp.445-450
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• 2002

A sensitive gas chromatographic method has been established for the determination of total iodide in seawater as their volatile organic derivative. The method is based on the formation of 4-iodo-2,6-dimethylphenol with 2,6-dimethylphenol in matrix and a single-step extraction of the derivative with ethyl ether, which are then measured by gas chromatography-mass spectrometry (selected ion monitoring). Iodate in sea water was completely reduced to iodide with ascorbic acid and acetic acid. The detection limit was 0.1 ng/mL in seawater and the calibration curve showed good linearity with r=0.9997. The method was sensitive, reproducible and simple enough to permit the reliable routine analysis of total iodide in seawater. Total iodide in sea water was found about 30 ng/ml.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.433-440
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• 2022

Environmental pollution caused by power plant exhaust gas is highlighted and eco-friendly regulations are being strengthened. However, due to the abundant reserves and low prices of coal, still the most used for power generation in the world. Therefore, flexible operation of coal-fired power plants to reduce emissions has become an inevitable option. However, lowering the output increases the possibility of acid dew point corrosion as the exhaust gas temperature decreases. The dew point corrosion occurs when condensable gases such as SO₃, HCl, NO₂ and H₂O cools below the saturation temperature. SO₃ is already well known to cause severe low- temperature corrosion in coal-fired power plants. Therefore, this study aims to prevent damage that may occur during operation by analyzing the dew point and corrosion resistance with exhaust gas temperature and sulfuric acid concentration of the power plant economizer tube.

• Journal of Industrial Technology
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• v.19
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• pp.409-413
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• 1999

Chemical oxidation of humic acid by ozonation process was investigated in the batch reactor. Aldehydes and ketone were identified as PFBOA derivatives in ozonated humic acid solutions using gas chromatography with PDECD. The formaldehyde was as a main by-product of ozonation. The characteristics of the formaldehyde production were discussed with respect to concentration at different experimental conditions.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.23-40
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• 1999

The analysis of thiodiglycolic acid in urine has been used as an index of biological exposure to vinyl chloride. Unfortunately thiodiglycolic acid has a strong hydrophilic character, because it has two carboxylic groups, so that it can only be extracted with organic solvent with a great difficulty. Underivatized thiodiglycolic acid tends to tail because of non-specific interaction with the inert support. Therefore, esterification is the obvious first choice for derivatization of thiodiglycolic acid, particularly for gas chromatography. In this study, the focus of interest is to compare two method of esterifications (methylation and silylation). Methylation is to make the methyl ester of thiodiglycolic acid by reaction with diazomethane. Silylation is to make the trimethylsilyl ester of thiodiglycolic acid by reaction with N-trimethylsily-ldiethylamine. The results and conclusions are as the following: 1. The detection limit (sensitivity) of methylated thiodiglycolic acid was $5.00{\mu}g/m{\ell}$ and silylated thiodiglycolic acid was $3.07{\mu}g/m{\ell}$ by gas chromatography with flame ionization detector. 2. The optimal liquid-liquid extraction of thiodiglycolic acid was as following: To each of the tubes, $15m{\ell}$ of urine, concentrated sulfuric acid (pH 1 - 2) and 5 gsodium sulfate were added. The samples was extracted three times with $5m{\ell}$ ethylacetate each time. 3. The methylated thiodiglycolic acid was more stable than silylated thiodiglycolic acid in extractional solvent which contained humidity. 4. The precision (pooled coefficient of variation for 4 days) of the analysis was 0.07324 in methylated thiodiglycolic acid with external standard calibration, and 0.07033 in methylated thiodiglycolic acid with internal standard calibration. 5. The precision (pooled coefficient of variation for 4 days) of the analysis was 0.10914 in silylated thiodiglycolic acid with external standard calibration, and 0.13602 in silylated thiodiglycolic acid with internal standard calibration. From the above results, the analysis of methylated thiodiglycolic acid was more sensitive (limit of detection) than silylated thiodiglycolic acid by gas chromatography. However, the methylated thiodiglycolic acid was stable in the humidity and was separated sharply on chromatogram. Also, analysis of methylated thiodiglycolic acid was more precise (pooled coefficient of variation for 4 days) than silylated thiodiglycolic acid. In conclusion, it is established that the analysis of methylated thiodiglycolic acid is appropriate for biological monitoring of exposure to vinyl chloride.

• Korean Journal of Food Science and Technology
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• v.6 no.2
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• pp.86-90
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• 1974

Quantitative analysis of the fatty acids contained in Amorpha-fruticosa seeds was carried out by means of gas chromatography with F.I.D. The general components and chemical constants have been performed with A.O.A.C methods. The results are summarized as follow: 1. General components of Amorpha-fruticosa seeds come out to be 17.65% moisture, 21.02% crude protein, 12.04% crude lipid and 5.37% ash. 2. Extraction of crude lipids were performed by soxhlet extractor for 14 hour. Amounts of the crude lipids were extracted 80.25% in ether, 80.00% in methanol, 77.34% in benzene and 69.96% in hexane. 3. Chemical constants of Amorpha-fruticosa seed oil were saponification number 178.67, acid number 3.11 and iodine number 54.27. 4. The fatty acid components of Amorpha-fruticosa seeds were quantitatively determined by gas chromatography to give 78.73wt% linoleic, 5.8wt% oleic, 5.68wt% palmitic, 4.8wt% stearic and 3.40wt% linolenic acid in ether solvent and to give 77.86wt% linoleic, 7.77wt% palmitic, 5.84wt oleic and 4.97wt% stearic acid in methanol solvent. The peak of capric acid was not found. Myristic, arachidic and lauric acids were very small.

• Korean Journal of Plant Resources
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• v.11 no.2
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• pp.202-209
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• 1998

Through total fatty acid analysis by the Gas chromatography, 17 different fatty acids were identified from the sap extracted from bark of Korean Rhus(Anacardiaceae), six species. Linoleic acid(C18 :2) and oleic acid(C18 : 1) were identified as major fatty acids for the species investigated, but except in R. chinensis.In the fatty acid composition for the species, one or two specific-fatty acid was detected, and its could be utilized as a useful taxonomic character.The result of cluster analysis by the 22 reliable characters in the fatty acid composition suggested first group was R.trichocarpa and R. succedanea, the second group, R.verniciflua, R.ambgua and R. sylvestris, but R.chinensis was a greatly independent species. The possible chemotaxonomic application of the fatty acid composition of bark in the genus Rhus was discussed.

• Food Science of Animal Resources
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• v.32 no.1
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• pp.112-117
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• 2012

In order to improve or replace the direct addition method of nitrite and ascorbic acid, the effect of nitrite and ascorbic acid-derived gas addition on color development and physical characteristics in emulsified sausage was investigated. Nitrite (150 ppm) and ascorbic acid (450 ppm) were added directly to emulsion in the control group, but in the treatment group nitrite and ascorbic acid-derived gas was used for emulsion. In the control and treatment groups, pH values were higher than raw meat, but these values did not show significant change during the storage in both groups. In the meat color, lightness (CIE $L^*$) and redness ($a^*$) values of control and treatment groups were higher compared to raw meat. The treatment group has lower redness and higher yellowness ($b^*$) values than control group during the storage (p<0.05). However, lightness was not significantly different between control and treatment groups. The cook and storage loss values were significantly different between control and treatment groups (p<0.05), but the water holding capacity and shear force values were not significantly different between groups. These results showed that treatment of nitrite and ascorbic acid-derived gas has a similar effect to direct addition of nitrite and ascorbic acid on color development and physical characteristics in emulsified sausage. Also, these results showed that nitrite and ascorbic acid-derived gas addition may be a good possible alternative of nitrite and ascorbic acid using in emulsified sausage.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.291-296
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• 2023

DIWS system was employed to treat hydrochloric acid gas from cold rolling mill process of iron and steel industry. Chlorine gas generated from the acid regeneration system was combined with hydrogen gas and hydrogen chloride gas was increased to 50%. After the injection of Na₂S₂O₃ to remove chlorine gas, the removal of hydrogen chloride was stably kept 87.5~88.8%, where the inflow was 13.1~13.4ppm and the outflow was 1.5~1.7ppm. DIWS system can be recommended for the real iron and steel plant because it was stably maintained not only the air emission standards but also the reduction of chemical usage.