• Analytical Science and Technology
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• v.8 no.4
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• pp.739-744
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• 1995

The two main methods to prepare water samples for analyzing volatile organic compounds(VOC's) were investigated. One is the purge and trap(PT) method and another is the head space(HS) sampling method. Both methods were effective to transfer the low boiling point components from the water sample onto the capillary column. The cryo-focusing at the top of the main capillary column was an effective way to obtain the sharpness of the chromatographic peaks but could be avoided when a semi-wide bore column was used. The recovery from the same amount of the sample was better in PT than in HS but a larger sample volume in HS method could compensate the lower efficiency. Therefore PT is suitable to the analysis of drinking water where the very low concentration must be determined. HS is suitable to waste water analysis because of the easiness of the operation. The repeatability was good and similar in both methods. For the contamination of the former sample, both methods were tough and could be used without any problems. The matrix effect which could change the equilibrium parameters in HS method was find negligible in many components. The actual samples such as tap water and river water were analyzed with both methods concerning 16 components regulated in Korea.

• Analytical Science and Technology
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• v.23 no.4
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• pp.383-388
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• 2010

Catalytic dissociation reaction was studied in order to transform waste plastics to oil by using noble metal supported catalysts. XRD, SEM, and GC/MSD analysis were performed to find the crystalline structure and shape, and product distribution. Generally, dissociation reaction occurs at low temperature compared to pyrolysis. Dissociation reaction has advantage of gasoline yield with respect to pyrolysis which products mainly $C_1\simC_4$. The result of dissociation reaction, gasoline was obtained much as a product. $C_5\simC_{11}$ compounds were produced as a gasoline product on Pt-zeolite among noble metal catalysts at $340^{\circ}C$. The conversion of dissociation reaction of waste plastics on the prepared catalyst was above 70% over $340^{\circ}C$.

• Journal of the Korean Electrochemical Society
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• v.11 no.1
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• pp.11-15
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• 2008

The composite membrane for direct methanol fuel cell (DMFC) was developed using $H_3O^+-{\beta}"-Al_2O_3$ powder and perfluorosulfonylfluroride copolymer (Nafion) resin. The perfluorosulfonylfluroride copolymer (Nafion) resin was mixed with $H_3O^+-{\beta}"-Al_2O_3$ powder and it was made to sheet form by hot pressing. The electrodes were prepared with 60 wt% PtRu/C and 60wt% Pt/C catalysts for anode and cathode, respectively. The morphology and the chemical composition of the composite membrane have been investigated by using SEM and EDXA, respectively. The composite membrane and $H_3O^+-{\beta}"-Al_2O_3$ were analyzed by using FT-IR and XRD. The methanol permeability of the composite membranes was also measured by gas chromatography (GC). The performance of the MEA containing the composite membrane (2wt% $H_3O^+-{\beta}"-Al_2O_3$) was higher than that of normal pure Nafion membrane at high operating temperature (e.g. $110^{\circ}C$), due to the homogenous distribution of $H_3O^+-{\beta}"-Al_2O_3$, which decreased the methanol permeability through the membrane and enhanced the water contents in the composite membrane.

• YAKHAK HOEJI
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• v.54 no.4
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• pp.215-225
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• 2010

To investigate effects of pine essential oil isolated by steam distillation from Pinus densiflora needles (PN) and twigs (PT) on anti-oxidant and anti-aging activities, the experiments were carried out to determine anti-oxidant and antiaging activities on DPPH radical scavenging activity, NBT/xanthine oxidase-superoxide scavenging activity, silica-induced intracellular $H_2O_2$ and hydroxyl radical generation in RAW264.7 cells, hyaluronidase and elastase activities in vitro. Essential oil of PN and PT were contained 0.225 and 0.176 (w/v) %, respectively. PN was contained with 30 kinds of essential oil and its major constituent is $\alpha$-pinene (21.5%). Further PT was contained with 40 kinds of essential oil and its major constituent is $\beta$-pinene (22.4%) in GC/MS assay. Other essential oils of PN were $\beta$-pinene, camphene, myrcene, limonene, terpinolene, $\alpha$-terpineol, bornyl acetate, $\alpha$-copaene, caryophellene and humulene and PT were $\alpha$-pinene, camphene, phellandrene, limonene, terpinolene, $\alpha$-terpineol, bornyl acetate, $\alpha$-copaene, caryophellene and humulene. The essential oil of PT have more active than that of PN in anti-oxidant activity which has significant DPPH radical and superoxide scavenging activity, and significant inhibitory activities on silica-induced intracellular $H_2O_2$ and hydroxyl radical generation, as well as, significantly inhibited elastase and hyaluronidase activities. Further, phellandrene, myrcene and $\alpha$-pinene have DPPH radical and superoxide scavenging activities, $\beta$-pinene, terpinolene, myrcene and phellandrene inhibited silica-induced intracellular $H_2O_2$ and hydroxyl radical generations. And also phellandrene and $\beta$-pinene inhibited hyaluronidase and elastase activities. In conclusion, the essential oils isolated from PN and PT have anti-oxidant and anti-aging activities.

• Journal of Photoscience
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• v.1 no.1
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• pp.31-37
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• 1994

Photoirradiation at > 300 nm onto a suspension of platinized TiO$_2$ (TiO$_2$-Pt) particles in an aqueous solution. of N$_{\varepsilon}$-carbamyI-L-lysine (Lys(CONH)$_2$) induced the selective N-cyclization of Lys(CONH$_2$) into almost optically pure L-pipecolinic acid (PCA) under argon atmosphere at ambient temperature. Among various TiO$_2$-Pt catalysts, a P-25 (Degussa) powder platinized via impregnation from chloroplatinic acid followed by hydrogen reduction at 753 K exhibited the highest photocatalytic activity for Lys(CONH$_2$) consumption and L-PCA production. GC-MS analyses of L-PCA obtained photocatalytically from $^{15}$N$\alpha$-Lys(CONH$_2$) revealed the selective formation $^{15}$N-substituted L-PCA. This implies that the mechanism for L-PCA production contains selective cleavage of C$_{\varepsilon}$-N bond and intramolecular alkylation at $\alpha$-amino group. Effect of pH on the rate of this photocatalytic reaction was investigated in detail and compared with the pH-dependent charge distribution in Lys(CONH$_2$) molecule. It is clarified that protonation-deprotonation of $\alpha$-amino group gives marked influence on the rate and selectivity of the photocatalytic reaction. On the basis of these results, it is concluded that the selective production of optically pure L-PCA, especially in an acidic suspension of TiO$_2$-Pt, was attributed to the enhanced protonation of $\alpha$-amino group to prevent undesirable oxidation by photogenerated positive holes and blocking of $\varepsilon$-amino group to yield racemic Schiff base intermediate.

• Journal of Ginseng Research
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• v.15 no.3
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• pp.257-262
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• 1991

1) 인삼 사포닌을 5% 황산으로 가수분해하여 TMS화 한 후 GC로 분석한 결과 인삼중의 모든 사포닌을 diol계 사포닌과 triol계 사포닌으로 나누어 분석할 수 있었다. 2) 시료중의 전체 diol계(PD)와 triol계(PT) 사포닌을 ginsenoside Rb$_1$과 Rg$_1$의 양으로 각각 환산하여 표시하고 미삼에는 백삼에 비해 diol계 사포닌의 함량이 많은 것을 이용하여 PD/PT글 구하고 여기에서 구해진 비를 이용하여 시료중의 백삼 및 미삼의 이론적 함량을 구할 수 있었다. 3) 이 방법의 검출 한계는 백삼의 양으로 0.14$\mu$g이었다.

• Analytical Science and Technology
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• v.10 no.4
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• pp.264-273
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• 1997

Anodic oxidation reaction was applied to remove trihalomethanes in an aqueous solution. Each component was determined by using solid phase microextraction(SPME) fiber and GC-ECD. Anodic and cathodic compartments were separated in order to protect contaminants and connected by $KNO_3$-agar bridge. The calibration graphs of the 6 THM components were shown good linearlity from a few ppb up to a few hundreds ppb concentration level. Anodes such as platinum(Pt), titanium(Ti). zircornium(Zr), titanium metal coated with iridium(Ti-Ir), and glassy carbon coated with mixed valence ruthenium(mv Ru) were tried to remove the THMs at different potentials. The best result was obtained on the Ti-Ir anode applied 9 volts DC. The electrode could effectively remove almost all the THM components from the stirring solution within about 1.5 hours. The glassy carbon electrode coated with mixed valence ruthenium showed excellent removing effect at the begining, but the maximum removing level was remained at 60% probably due to the destruction of the electrode surface. The concentration of chloroform, however, tends to be increased due to the electrode reaction producing the component at the condition.

• Journal of the Korean Chemical Society
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• v.50 no.2
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• pp.163-177
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• 2006

Alpha Nickel hydroxide samples have been synthesized by electrodeposition on platinum and nickel substrates at current densities of 1, 5, 6, 7 and 10 mAcm？2 at a controlled temperature of 30.00 oC from Ni(NO3)2 bath. Platinum substrate shows a tendency to incorporate less nitrate ions with increase in current density thus producing less hydroxy-deficient nickel hydroxide layers. On the whole the interlayer distance (d003) is found to be inversely proportional to the amount of nitrate ions incorporated in-between the lattice. For the first time we have observed a decrease in lattice spacing with increase in concentration of intercalant (anions) and the reason for lattice contraction is attributed to the columbic attractive forces exerted by the oppositely charged nitrate ion and positively charged slabs. The Infrared spectra of the samples with expanded interlayers show two types of OH vibrations corresponding to hydrogen bonded and non-hydrogen bonded OH groups whereas the contracted interlayers show only hydrogen-boded OH groups. Although the faradaic efficiency is found to increase with increase in applied current there is a local minimum at 6.0 mAcm？2 current density on both platinum and nickel substrates. In this manuscript, GC-MS data is provided which clearly demonstrates the electrodeposited nickel hydroxide sample to consist of huge amount of carbonate ions although the electrolyte solution in nickel nitrate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.7
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• pp.965-970
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• 2003

This study has been performed to develope a method for the simultaneous determination of 1,4-dioxane (DOX), epichlorohydrin (EPC), propylene chlorohydrin (PCH), ethylene chlorohydrin (ECH) and 1,3-dichloro-2-pro-panol (DCP) in polysorbates, chloline chloride, choline bitartrate, modified starch and spices by purge and trapgas chromatography. Experimental design was used to select a suitable trap by measuring the limit of detection (LOD) and to investigate the effect of temperature and salt of extraction, and the percentage of recovery in various matrix. The LOD of DOX, EPC, PCH, ECH and DCP were 1.38$\mu\textrm{g}$, 0.23$\mu\textrm{g}$, 3.30$\mu\textrm{g}$, 3.97$\mu\textrm{g}$, 20.43$\mu\textrm{g}$ respectively, by means of using Vorcarb 3000 trap with 5$0^{\circ}C$ sample sparger. Excluding EPC, the recoveries of target compounds were above 90% in all matrix. Target compounds in polysorbates (17), choline chloride (5), choline bitartrate (5), modified starch (8) and spices (25) were not detected. But 2.5 ppm of DOX was detected in Tween 80.

• The Journal of Internal Korean Medicine
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• v.38 no.6
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• pp.944-954
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• 2017

Objectives: This study investigated the anti-inflammatory effects of Jageum-jung extract on Dextran sulfate sodium (DSS-induced) ulcerative colitis in mice. Methods: Ulcerative colitis was induced by DSS in Balb/C male mice. Ten mice were assigned to each of four groups: Ctrl (control), UE (ulcerative colitis-induced), PT (treated with pentasaccharide after induction of ulcerative colitis), and JT (treated with Jageum-jung extract after induction of ulcerative colitis). The effects of Jageum-jung extract were measured by restoration of the length of the intestine, degree of mucosal damage as seen with histochemistry, and changes of p-IkB, iNOS, COX-2, and caspase-3 determined by immunohistochemistry. Results: The recovered intestinal length of the JT group was longer than that of the UE group. In the colon mucosa of JT group, hemorrhagic lesions were reduced, and the mucus barrier was recovered. This group also showed inhibited production of inflammatory enzymes (iNOS, COX-2) through regulation of proinflammatory enzyme (NF-kB, p65) activity in the colon. In addition, caspase 3 activation induced apoptosis. By GC/MS analysis, azetidine was identified. Conclusions: This study confirmed the anti-inflammatory effects of jageum-jung extract, and suggests the possibility of using Jageum-jung extract to treat ulcerative colitis. Further experiments and research on the mechanism of Jageum-jung effects are needed.