• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.202-211
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• 2011

In this study the seasonal and spatial pattern of mercury (Hg) concentrations in multimedia environments were investigated in Lake So-Yang. Total mercury (TM) in water column greatly enhanced as turbidity and particulate organic carbon (POC) increased due to the severe runoff, suggesting that most of Hg existed as particulate Hg in Lake Soyang. We also collected 22 species of fish in Lake Soyang and Han River, and the average total mercury in fish was 0.073 ppm, lower than both Korean (0.5 ppm) and EPA criteria (0.3 ppm). However when considering the amount of fish intake for Korean the Hg criterion in fish must be more stringent than current value, and the advisory for fish consumption should be made. Hg in fish considerably varied with sampling sites, having the highest in the upper region (Yang-gu) and the lowest in downstream (Han River). This spatial variation was possibly derived by "bloom dilution" associated with high phosphorus loading or elevated DOC concentrations, or both. Total mercury in sediment varied from 69.9 to $98.3{\mu}g/kg$, which was relatively lower than those measured in Voyageurs National Park in Minnesota in USA ($102{\sim}364{\mu}g/kg$).

• Journal of Korean Society of Environmental Engineers
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• v.29 no.8
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• pp.909-914
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• 2007

Fluorine compounds are the essential chemicals for wet processes of semiconductor and LCD production line. Problems of conventional treatments for fluoride wastewater are their high operation costs and low fluoride removal capacity. In this study, cement paste containing various Ca-bearing hydrates such as portlandite, calcium silicate hydrate(CSH), and ettringite was investigated for fluoride removal. The objectives of this study are to assess the feasibility of using cement paste cured mixture of cement and water as an alternative agent for treatment of fluoride wastewater and to investigate fluoride removal capacity of the cement paste. The performance of cement paste was comparable to that of lime in the kinetic test. In column experiment where the effluent fluoride concentrations were below 0.5 mg/L. Then the leached calcium reached the maximum level of 800 mg/L. The nitrate reduced to the level of less than 10 mg/L. Nitrate in the wastewater was exchanged with interlayer sulfate of these cement hydrate LDHs. Phosphate concentration could be reduced to 10 mg/L by forming calcium phosphate. These results indicate that the cement paste generally has advantageous characteristics as an economical and viable substitute for lime to remove fluoride.

• Journal of Pharmaceutical Investigation
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• v.35 no.2
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• pp.123-127
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• 2005

An HPLC method was employed for the determination of ethambutol in human plasma. After addition of internal standard (IS, octylamine, $2\;{\mu}g/mL$) and alkalinization of the plasma with 5 M sodium hydroxide, the drug and IS were extracted into the mixture of chloroform and diethyl ether (40:60, v/v). Following a 15-min vortex-mixing and a 10min centrifugation, the organic phase was spiked with $100{\mu}L$ of phenylethylisocyanate $(2000{\mu}g/mL)$ for chemical derivatization, mixed for 5 min and evaporated to dryness under a stream of nitrogen. The residue was reconstituted with $100{\mu}L$ of mobile phase and $20{\mu}L$ was injected into C18 column with a mobile phase consisting of methanol:water (70:30, v/v). The samples were detected utilizing an ultraviolet detector at 200 nm. The method was specific and validated with a limit of $0.15\;{\mu}g/mL$. Intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification. The applicability of this method was demonstrated by analysis of human plasma after oral administration of a single 1200-mg dose to 20 healthy subjects. From the plasma ethambutol concentration vs. time curves, the mean AUC was $9.61{\pm}1.64\;{\mu}g{\cdot}hr/mL$ and Cmax of $2.68\;{\mu}g/mL$ reached 2.73 hr after administration. The mean biological half-life of ethambutol was $3.46{\pm}1.21$ hr. Based on the results, this simple and validated assay could readily be used in any pharmacokinetic studies using humans.

• Journal of Pharmaceutical Investigation
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• v.39 no.1
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• pp.73-78
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• 2009

A simple LC-MS/MS method of rabeprazole in human plasma was developed and validated. Rabeprazole and Internal standard (I.S), omeprazole, were extracted from human plasma by liquid liquid extraction, chromatographic separation of rabaprazole in plasma was achieved at $45^{\circ}C$ with a Shiseido UG120 $C_{18}$ column and methanol-10 mM ammonium acetate buffer (pH 9.42 with ammonium water), as mobile phase. Rabeprazole produced a protonated precursor ion [$(M+H)^+$] at m/z 360.10 and corresponding product ion at m/z 242.21. Internal standard produced a protonated precursor ion [$(M+H)^+$] at 346.09 and corresponding product ion at m/z 198.09. This method showed linear response over the concentration range of $1{\sim}500\;ng/mL$ with correalation coefficient greater than 0.99. The lower limit of quantitation (LLOQ) using 0.2 mL plasma was 1 ng/mL, which was sensitive enough for pharmacokinetics studies. The method was specific and validated with a limit of quantitation of 1 ng/mL. The intra-day and inter-day precision and accuracy were acceptable for all samples including the LLOQ. The applicability of the method was demonstrated by analysis of plasma after administration of a single 10 mg dose to 36 healthy subject. From the plasma rabeprazole concentration versus time curves, the mean $AUC_t$ (The area under the plasma concentration-time curve from time 0 to 12 hr ) was $691.36{\pm}321.88\;ng{\cdot}hr/mL$, $C_{max}$ (maximum plasma drug concentration) of $353.21{\pm}131.52\;ng/mL$ reached $3.4{\pm}1.1\;hr$ after adiministration. The mean biological half-life of rabeprazole was $1.37{\pm}0.75\;hr$. Based on the results, this simple method could readily be used in pharmacokinetics studies.

• Analytical Science and Technology
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• v.6 no.5
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• pp.471-477
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• 1993

The novel macrocylic ligand {(4, 5):(13, 14)-dibenzo-6, 9, 12-trioxa-3, 15, 21, -triazabicyclo [15. 3. 1]heneicosa-(1, 17, 19)(18, 20, 21) triene: HDBPDA} was synthesized, and protonable constants of the ligand and the complex stability constants with alkali metals alkaline earth metals were determined. We evaluated the resolution factor(${\Delta}$) from equation that inducing from stability constants(pK). Also, this ligand was grafted on chloromethylated styrene-divinyl benzene(Merrifield resin) for HDBPDA, ion exchanger. Alkali and alkaline earth metal ions were separated using water by the column chromatography with this ion exchanger. Selectivity(${\alpha}$) and resolution(Rs) of alkali and alkaline earth metal ions were measured from the elution curves chromatogram. The selectivity and resolution values of the various ions calculated from the elution curves were compared with those abtained from pK values. The results were in a good agreement between tow methods. Ion exchange capacity of the resin were determined using the alkali and alkaline earth metal ions and pH dependence of capacity was also discussed.

• Korean Journal of Food Science and Technology
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• v.39 no.1
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• pp.77-82
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• 2007

From the total methanolic extract of Chrysanthemum coronarium L. var. spatiosum (Compositae), nitrite scavenging ability and superoxide dismutase (SOD)-like activity were analyzed as antioxidative characteristics. After successive partitioning with chloroform, n-butanol, and water, the chloroform fraction showed the most significant nitrite scavenging ability with an $IC_{50}$ value of 39 ppm compared with the values of vitamin C and chlorogenic acid, 15 ppm and 36 ppm, respectively. The active fraction was subjected to silica gel and Sephadex LH-20 column chromatography, and the compound was isolated and identified as ${\beta}-sitosterol-O-{\beta}-D-glucoside$ using $^{1}H-NMR$ and $^{13}C-NMR$ spectral data. The glucoside was further hydrolyzed and confirmed as a glycosylated ${\beta}-sitosterol$. The compound and its aglycone, ${\beta}-sitosterol$, showed different nitrite scavenging and SOD-like activity. The $IC_{50}$ value of nitrite scavenging ability of the compound was 335 ppm at pH 1.5, while that of its aglycone was 41 ppm. As for the SOD-like activity, the $EC_{50}$ values of the sterol and the glucoside were 1,291 ppm and >2,000 ppm, respectively, compared with those of vitamin C and chlorogenic acid, 38 ppm and 449 ppm, respectively.

• Applied Chemistry for Engineering
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• v.16 no.3
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• pp.348-353
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• 2005

The extracts from natural and fermented products such as Artemisia plants, Rhodiola Salientness, fermented soybeans and soybean paste were used to investigate the whitening effect. 10 g of Artemisia plant were added to 300 mL of ethanol and extracted by sonification at room temperature for 3 h. The extract was further partitioned by the equal volume percent in the order of the n-hexane, chloroform and ethyl acetate. 5 g of Rhodiola salientness was also added to 150 mL of methanol and extracted at the room temperature for 12 h. The effluents from a chromatographic column ($3.9{\times}250mm$, $C_{18}$, $15{\mu}m$) were collected and concentrated in two parts. The extraction of fermented soybeans and soybean paste were done by 60% ethanol. In this work, tyrosinase inhibitory activity and melanin inhibitory effect were measured to confirm the whitening effect. The water layer of Artemisia princeps Pampan showed the good inhibitory of antioxidant, while the hexane layer of Artemisia iwayomogi Kitamura and the chloroform layer of Artemisia princeps Pampan had the excellent melanin inhibitory effect. The Rhodiola salientness had the superior whitening effect to the arbutin in in-vivo melanin production ratio assay. However, the fermented soybeans and soybean paste did not show any whitening effect.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.178-182
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• 2006

The purpose of this research is to remove the bromate that is a disinfection by-poduct of water purification by ozone. I achieved a high rate of removal with iron, copper, or silver impregnated activated carbon by using both the adsorbing power of granular activated carbon and the oxidizing power of metal ions as deoxidizing agents. In the removal test of bromate with the quantity of activated carbon input I injected each activated carbon by 0.1, 0.3, 0.1, and 1.0 g and let them react for 240 minutes. I found the quantity of removed bromate was in proportion to the amount of input. The removal rate of bromate increased about 20% when I used acid treated activated carbon. The metal impregnated activated carbon had a higher removal rate of bromate than that of general activated carbon by about $30{\sim}50%$. Iron impregnated activated carbon showed a 92% removal rate of bromate. Iron, copper, or silver impregnated activated carbon removed about $0.9{\sim}1.5mg\;{BrO_3}^-/g$ while general activated carbon removed about $0.02{\sim}0.45mg\;{BrO_3}^-/g$. In the continuous column reaction, there were breakthrough phenomena at 96, 180, and 252 hours when I tested EBCT by 1, 2 and 3 minutes while I was changing the flux rate of bromate from 15.6 to 46.8 mL/min.

• Ocean and Polar Research
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• v.26 no.2
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• pp.287-298
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• 2004

As a part of Korea Deep Ocean Study program, we investigated the distribution of planktonic protists in the upper 200 m of the northeast Pacific from $5^{\circ}N$ to $17^{\circ}N$, along $131^{\circ}30'W$. Area of divergence was formed at $9^{\circ}N$ which is boundaries of the north equatorial counter current (NECC) and the north equatorial current (NEC) during this cruise. Chlorophyll-a concentration was higher in NECC than in NEC area. Pico chl-a(<$2\;{\mu}m$) to total chl-a accounted for average 89% in the study area. The contribution of pico chl-a to total chl-a was relatively high in NEC area than in NECC area. Biomass of planktonic protists, ranging from 635.3 to $1077.3\;mgC\;m^{-2}$(average $810\;mgC\;m^{-2}$), was most enhanced in NECC area and showed distinct latitudinal variation. Biomass of HNF ranged from 88.7 to $208.3\;mgC\;m^{-2}$ and comprised 15% of planktonic protists. Biomass of ciliates ranged from 123.6 to $393.0\;mgC\;m^{-2}$ and comprised 25% of planktonic protists. Biomass of HDF ranged from 407.2 to $607.8\;mgC\;m^{-2}$ and comprised 60% of planktonic protists. HDF was the most dominant component in both NECC and NEC areas. Nano-protist biomass accounted for more than 50% of total protists in the both areas. The contribution of nanoprotist to total protists biomass was relatively higher in NEC area than in NECC. The biomass of planktonic protists was significantly correlated with phytoplankton biomass in this study area. The size structure of phytoplankton biomass coincided with that of planktonic protists. This suggested that the structure of the planktonic protists community and the microbial food web were dependent on the size structure of the phytoplankton biomass. However, biomass and size structure of planktonic protist communities might be significantly influenced by physical characteristics of the water column and food concentration in this study area.

• Microbiology and Biotechnology Letters
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• v.14 no.5
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• pp.371-376
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• 1986

This study to elucidate concentrations of impurities such as methanol and fusel oil formed during fermentation process among the different materials and has been applied technical seperation for processing improvement by continuous distillation of super-allospas type. Methanol was formed high concentrations of cutting dried sweet potato and tapioca in order among the different materials during fermentation process. n-Propanol oil was formed high concentration of rice, cutting dried sweet potato, corn, naked barley and tapioca in order among the those materials. I-Buthanol showed high concentration of tapioca, corn, rice, cutting dried sweet potato and naked barley in order and isoamyl-alcohol showed high concentration of tapioca, rice, cutting dried sweet potato, corn and naked barley in order. Using the continuous distillation of super-allospas type, the following are collection ratios of n-propanol, iso-butanol, n-butanol and iso-amylalcohol: 37.9％, 28.6％, 37.4％, and 56.1％ when 78.25％ (v/v), 68.54％ (viv), 50.0％ (viv), and 50.0％ (v/v) alcohol are used, respectively. Fusel oil and bad alcohol put into the recovery column and then seperated directly by side cut of fusel oil partially from plate of tower bottom after concentration again. Extra impurities seperated by fusel oil seperator when 20 ％ (v/v) alcohol adjusted with water.