• Analytical Science and Technology
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• v.7 no.3
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• pp.421-425
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• 1994

A micro-high performance liquid chromatography(Micro-HPLC) techniquie with solid phase extraction was reported which detected carbendazim and carbaryl at picogram levels. They were separated on microbore packed $C_{18}$ column($1.0mm\;I.\;D{\times}150mm$, $d_f=5{\mu}m$) using a 50% methanol mobile phase and detected at UV 220nm(${\alpha}=2.94$, $R_s=4.71$), while they were not resolved on analtical HPLC system(${\alpha}=1.27$, $R_s=0.76$). The detection thresholds of carbendazim and carbaryl were 0.5ng and 0.1ng on Micro-HPLC, therefore Micro-HPLC system was 20~40 told more sensitive than anayltical HPLC system. Sep-Pak $C_{18}$ catridge was found to be efficient in enriching carbendazim and carbaryl from dilute aqueous solution with 97.0% and 97.8% recoveries of them. The Sep-Pak $C_{18}$ catridge followed by the Micro-HPLC had been applied to the quantitative analysis of carbendazim and carbaryl in spiked juices and a commercial drinking water.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.4
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• pp.183-188
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• 1978

In this study, gas chromatographic analysis was carried out on volatile constituents of cooked squid for the object of obtaining information on the characteristic flavor of the cooked squid meat. The results obtained are as follows: 1) Methanol was the most effective solvent for the extraction of volatile constituents of squid meat. 2) Twenty five and thirty two peaks were detected from the condensate collected in cold traps which were immersed in ice water and dry ice-acetone, respectively. In these compounds, five kinds of volatile organic acids such as acetic acid, butyric acid, iso-valeric acid, valeric acid, and caproic acid were identified. 3) Eleven peaks were detected from the head space vapor collected in cold trap which is immersed in liquid nitrogen. Volatile amines identified in these components are as follows; methylamine, trimethylamine, dimethylamine, ethylamine, and iso-propylamine.

• International Journal of Industrial Entomology and Biomaterials
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• v.33 no.1
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• pp.24-30
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• 2016

1-Deoxynojirimycin (DNJ) have been extensively investigated for their α-glucosidase inhibitor on postprandial hyperglycemia, and applied in nutraceuticals and medicine for preventing or delaying progression of type 2 diabetes. However, the amount of DNJ in mulberry leaves is low (about 0.1%), therefore, more effective extraction method is needed. This study was performed to develop microbial DNJ for biological methods of DNJ as an alternative to the chemical methods. In this study, we obtained evidence for Bacillus subtilis that produce DNJ in large quantities by high performance liquid chromatography. Inhibition of α-glucosidase activity was determined to DNJ production or non-production. Investigation of the effect of mulberry leaves powder concentration (1~5%), using the DNJ high-production bacteria, provided evidence for microbial mass production of DNJ. When the 4% mulberry leaf powder for 9 days was used, the α-glucosidase inhibitory activity was over the 85%. Also, the results presented in this study confirm DNJ yield's increasement in microbes using the various of nutrients and provide insight of ways to improve DNJ yields in microorganisms.

• Journal of ILASS-Korea
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• v.15 no.2
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• pp.83-93
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• 2010

Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damage, which will increase as operating time progresses. Several nuclear power plants in Korea have experienced wall thinning damage in the area around the impingement baffle inside feedwater heater installed downstream of the turbine extraction stream line. At that point, the extract steam from the turbine is two phase fluid at high temperature, high pressure, and high speed. Since it flows to reverse direction after impinging the impingement baffle, the shell wall of feedwater heaters may be affected by flow-accelerated corrosion. In this paper, to compare degree of shell wall thinning mitigation rate to squared type with mitigation rate of other type baffle plate, four different types of impingement baffle plate-squared, curved, mitigating type and multi-hole type-applied inside the shell. With these comparison data, this paper describes operation of experiments and numerical analysis which is composed similar condition with real feed water heater. And flow visualization is operated for verification of experiments and numerical analysis. In conclusion, this study shows that mitigating type and multi-hole type baffle plate are more effective than other baffle plate about prevention of pressure concentration and pressure value decrease.

• Carbon letters
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• v.16 no.3
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• pp.171-182
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• 2015

Mesophase pitch is an important starting material for making a wide spectrum of industrial and advanced carbon products. It is produced by pyrolysis of petroleum residues. In this work, mesophase formation behavior in petroleum residues was studied to prepare environmentally-benign mesophase pitches, and the composition of petroleum residues and its influence on the mesophase formation was investigated. Two petroleum residues, i.e., clarified oil s (CLO-1, CLO-2) obtained from fluid catalytic cracking units of different Indian petroleum refineries, were taken as feed stocks. A third petroleum residue, aromatic extract (AE), was produced by extraction of one of the CLO-1 by using N-methyl pyrrolidone solvent. These petroleum residues were thermally treated at 380℃ to examine their mesophase formation behavior. Mesophase pitches produced as a result of thermal treatment were characterized physico-chemically, as well as by instrumental techniques such as Fourier-transform infrared spectroscopy, nuclear magnetic resonance, X-ray diffraction and thermogravimetry/derivative thermogravimetry. Thermal treatment of these petroleum residues led to formation of a liquid-crystalline phase (mesophase). The mesophase formation behavior in the petroleum residues was analyzed by optical microscopy. Mesophase pitch prepared from CLO-2 exhibited the highest mesophase content (53 vol%) as compared to other mesophase pitches prepared from CLO-1 and AE.

• Proceedings of the Korean Environmental Health Society Conference
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• 2002.04a
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• pp.9-12
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• 2002

Diffusive transport of volatile organic compounds(VOCs) and their degradation by bacteria in unsaturated soils are couple by poorly understood mass transfer kinetics at the gas/water interface. Determination of the fate of VOCs in unsaturated soil is necessary to evaluate the feasibility of natural attenuation as a VOC remediation strategy. The objective of this study was to develop a mechanistically based mathematical model that would consider the interdependence of VOC transport, microbial activity, and sorptive interaction in a moist, unsaturated soil. Because the focus of the model was on description of natural attenuation, the advective VOC transport that is induced in engineered remediation processes such as vapor extraction was not considered. The utility of the model was assessed through its ability to describe experimental observations form diffusion experiments using toluene as a representative VOC in well-defined soil columns that contained a toluene degrading bacterium, Pseudomonas Putida, as the sole active microbial species. The coefficient for gas-liquid mass-transfer, K$\sub$LA/, was found to be a key parameter controlling the ability of bacteria to degrade VOCs. This finding indicates that soil size and geometry are likely to be important parameters in assessing the possible success of natural attenuation of VOCs in contaminated unsaturated soils.

• Molecular & Cellular Toxicology
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• v.1 no.2
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• pp.87-91
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• 2005

Although 2D-PAGE has been widely used as the primary method for protein separation, difficulties in displaying proteins with an extreme values of isoelectric paint (pI), molecular size and hydrophobicity limit the technique. In addition, time consuming steps involving protein transfer and extraction from the gel-pieces can result in sample loss. Here, we describe a novel protein separation technique with capillary size-exclusion chromatography (CSEC) for rapid protein identification from human plasma. The method includes protein fractionation along with molecular size followed by in-solution tryptic digestion and peptide analysis through reversed phase liquid chromatography (RPLC) coupled to nanoflow electrospray-tandem mass spectrometry (ESI-MS/MS). Tryptic peptides are applied an a $100\;{\mu}m\;i.d.{\times}10mm$ length pre-column and then separated on a $75\;{\mu}m{\times}200mm$ analytical column at -100 nL/min flaw rate. Proteins were identified over the wide ranges of pI (3.7-12.3) when this technique was applied to the analysis of $1-2\;{\mu}L$ of human plasma. This gel-free system provides fast fractionation and may be considered a complementary technique to SDS-PAGE in proteomics.

• Food Science and Biotechnology
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• v.15 no.2
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• pp.183-188
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• 2006

The tocopherol and tocotrienol contents of 39 vegetable oils, margarines, butters, and peanut butters typically consumed in the Korea diet were determined by direct solvent extraction method followed by normal phase liquid chromatography. All samples were locally obtained in the Cheongju area in 2003 and 2004. The study examined data on 19 vegetable oils, 10 margarines, 6 butters, and 4 peanut butters. ${\gamma}$-Tocopherol (${\gamma}$-T) and ${\alpha}$-tocopherol (${\alpha}$-T) were detectable in all products except butters and were usually present in the vitamin E form in greater quantity than the other isomers. Usually, ${\gamma}$-T content was higher than ${\alpha}$-T content in many samples. Tocotrienols were measurable in some samples but usually at levels less than the corresponding tocopherols. Three analytical method validation parameters, accuracy, precision, and specificity, were calculated to ensure the method's validity and were all confirmed to be reliable and satisfactory.

• Archives of Pharmacal Research
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• v.29 no.12
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• pp.1096-1101
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• 2006

Armeniacae Semen not only contains amygdalin, but emulsin also, which is an enzyme that hydrolyzes amygdalin. The extraction yield of amygdalin from Armeniacae Semen was low, due to the presence of emulsin, when extracted with water. When Schizandrae Fructus solution was used as the extractant; however, amygdalin was almost completely extracted, regardless of the cutting size, due to the absence of the influence of emulsin. In addition, when the crude powder or small piece forms were used with Schizandrae Fructus solution, on epimerization of the D-amygdalin into neoamygdalin occurred. D-amygdalin and its conversion product, neoamygdalin, were quantitatively analyzed by reverse-phase, high-performance liquid chromatography (HPLC), with an optimized eluent of 10 mM sodium phosphate buffer (pH 2.3), containing 11.5% acetonitrile. The concentration and detector response were linearly correlated over the range 0.05 to 2 mM. The detection limits for both D-amygdalin and neoamygdalin were approximately $5\;{\mu}M$ for the amount injected.

• Korean Journal of Pharmacognosy
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• v.26 no.4
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• pp.419-425
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• 1995

Corydalis remota Fish. ex Max. (Papaveraceae) is a well known medicinal plant being used as analgesics or anticonvulsive in oriental medicine. As the alkaloid content is known to vary depending on the environmental factors, the technology of plant tissue culture can be adopted as source of Corydalis-alkaloids. The present study describes an establishment of tissue cultures of Corydalis which produce alkaloids consistently. Callus were induced from immature seeds of Corydalis remota by placing the seeds on MS static media containing NAA(0.25, 1.0 and 4.0 mg/l, respectively). The combined treatment of NAA(1.0 mg/l) with cytokinin(BAP 0.5 mg/l) improved the induction of callus. TLC scanning data followed by sequential extraction and purification revealed that the induced callus contains a significant amount of alkaloids. Cell suspension cultures were established by transferring the induced callus into the liquid media with the same condition of plant growth regulators as the callus culture.