• Clean Technology
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• v.20 no.3
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• pp.251-255
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• 2014

PVA gel beads were made by immobilization of thenoyltrifluoroacetone (HTTA) and trioctylphoshineoxide (TOPO) with poly vinyl alcohol (PVA). The prepared PVA gel beads were used for the removal of $Cu^{2+}$ from aqueous solution. The removal characteristics of $Cu^{2+}$ by PVA gel beads was found to follow the pseudo-second-order kinetic equation. The maximum removal capacity calculated from Langmuir isotherm equation was 9.59 mg/g. The optimal pH was in the range of 3.5~6. Even when the PVA gel beads were reused 5 times, the leakage of extractant and the damage of PVA gel beads was not observed.

• Journal of Soil and Groundwater Environment
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• v.12 no.5
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• pp.73-85
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• 2007

In this study, the experiment of solid-phase microextraction (SPME) technique using GC/FID was conducted as a possible alternative to liquid-liquid extraction for the analysis of EGBE, DGBE, DBM and TGME in water, and also, an optimization condition of trace analysis for disel oxygenates including EGBE by the design of experiment (DOE) was described. Experiments used a fractional factorial design method followed by central composite design allowing optimization of a number of factors as well as statistical analysis of the results. The response surface analysis showed that the extraction efficiency could be represented by a second-order polynomial equation in which the salts concentration, extraction temperature, extraction time and sonication time are the major influences. Using DOE method, a new datadependent method was developed to improve the quantity of confidently analyzed disel oxygenates in water samples.

• Analytical Science and Technology
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• v.23 no.2
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• pp.119-127
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• 2010

An effective method for the simultaneous analysis of ${\beta}$-lactams from surface water was established. After solid-phase extraction with HLB (Hydrophilic Lipohilic Balance) cartridge at pH 2, seven ${\beta}$-lactams (amoxicillin, ampicillin, penicillin G, cefaclor, cefadroxil, cefatrizine and cephradine) were determined using LC/ESI-MS/MS. In this newly established method, correlation coefficients ($r^2$) of calibration curves for seven ${\beta}$-lactams in blank surface water appeared to be 0.9911~0.9995 in the concentration range of 0.01~1.0 ng/mL. The limits of detection (LODs) and the limits of quantificaiton (LOQs) in spiked surface water were shown to be 0.0003~0.0234 ng/mL and 0.0046~0.0778 ng/mL, respectively. The developed method is believed to serve as a rapid and reliable method for the qualitative and quantitative analysis of residual ${\beta}$-lactam antibiotics from aquatic environment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.359-363
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• 2009

This study was performed to establish a rapid and simple analytical method for niacin (nicotinic acid and nicotinamide) using HPLC. A pretreatment method for the extraction and clean-up of niacin in infant formula sample and an instrumental condition for HPLC were optimized. Niacin was extracted by 5 mM hexanesulfonate with ultrasonication for 30 min. For the clean-up of the sample, the extract was applied to a HLB cartridge, and then niacin was eluted from the cartridge using 5 mL of 80% methanol after washing with 5 mL of n-hexane. The total recoveries were $83{\sim}104%$ and relative standard deviation were in the range of $1.5{\sim}3.5%$ during the extraction and clean-up process. Niacin was determined by gradient elution with sodium hexanesulfonate/methanol buffer as a mobile phase and a photodiode array detector (260 nm). It showed a high linearity between the content of niacin and the peak area ($r^2$=1.000) in the range of $0.02{\sim}10.0$ mg/L of nicotinic acid and nicotinamide. The detection limit was 0.02 mg/L (0.2 mg/kg in the sample). The method was successfully applied for the determination of niacin in infant formula. Total niacin contents were in the range of $53.5{\sim}140.3$ mg/kg.

• Analytical Science and Technology
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• v.23 no.4
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• pp.405-413
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• 2010

A new method for the simultaneous determination of six glucocorticoids (betamethasone, dexamethasone, prednisone, prednisolone, methylprednisolone, and flumethasone) in meats (bovine muscle, bovine liver) were established. Samples were effectively extracted using C18 cartridge with ethylacetate. Chromatographic separation was achieved using C18 column and negative electrospray ionization mass spectrometry was performed in the Multiple Reaction Monitoring mode for the effective quantitation and qualification of glucocorticoids. Acetonitrile and water (0.1% formic acid) were used as mobile phase and additive for effective electrospray ionization, and gave good chromatographic separation and mass spectrometric sensitivity. The limit of detection (LODs) and the limit of quantitation (LOQs) in spiked blank samples depending on types of matrix and pharmaceuticals were ranged from 0.2 to $1.0\;{\mu}g$/kg and 0.8 to $3.4\;{\mu}g$/kg, respectively. And the recoveries were between 89.5 to 119.6%. The established method showed good recoveries, accuracies, precisions and fast sample preparation and it will be applied to assay of glucocorticoids residues in meat.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.626-632
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• 2011

Phoxim, which is one of veterinary drugs, is a well-known antiparasitic agent in wide use. In this paper, phoxim was extracted from cattle and pig tissue using solid-phase extraction (SPE) employing a silica cartridge with acetonitrile. Liquid chromatography/electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS) for the analysis of phoxim from animal tissue was presented. Phoxim was detected on a $C_{18}$ column ($2.1{\times}100\;mm$, $3.5\;{\mu}m$) using a mobile phase of 0.1% formic acid in water and acetonitrile. A linear correlation observed in the calibration curves for cattle (0.0048~2.0 mg/kg) and pig (0.0055~2.0 mg/kg) showed above $r^2$=0.995. Accuracy measured at concentrations ranging from 0.0048 to 0.2 mg/kg was the range of 68.2~106.9%. Limit of detection (LOD) and limit of quantitation (LOQ) were the range of 0.0014~0.0017 mg/kg and 0.0048~0.0055 mg/kg, respectively. The precision (RSD%) was below 11.2%.

• The Korean Journal of Pesticide Science
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• v.4 no.1
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• pp.26-31
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• 2000

An analytical method was approached to determine the residues of benzimidazole fungicides in soybean sprouts and was compared with traditional solvent-based method of extraction, solid phase extraction(SPE) and matrix solid phase dispersion(MSPD). The recoveries of carbendazim for liquid-liquid extraction (LLE), SPE and MSPD in soybean sprouts were $69.25{\sim}79.16$, $79.99{\sim}90.42$ and $92.40{\sim}98.48%$, respectively. The recoveries of thiabendazole for LLE, SPE and MSPD in soybean sprouts were $64.86{\sim}83.26$, $79.12{\sim}94.04$ and $65.44{\sim}73.92%$, respectively. The residues of carbendazim by elapsed time under our cultivated soybean sprouts program found $0.10{\sim}0.25$ mg/kg after 5 days and trace concentration of carbendazim was detected after 7 days. Of the 448 samples analyzed, less than 1.5% had residues of carbendazim ranged from 0.05 to 0.37 mg/kg.

• Clean Technology
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• v.14 no.2
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• pp.110-116
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• 2008

The radioactive wastes generated from the nuclear industry can be divided into the forms of solid, liquid, or gas. Radioactive methyl iodide, a gaseous radioactive waste, is absorbed by activated carbon with 5 wt% of Trietylenediamine (1,4-diazania-bicycle[2.2.2]octane, TEDA) impregnated on the surface. Methyl Iodide ($CH_3I$) is combined chemically with TEDA (the final product : I-TEDA). To recycle radioactive activated carbon, removal of I-TEDA from activated carbon is needed. A wet method for recycling impregnated active carbon was developed to remove radioactive I-TEDA using an acetonitrile solution, which produces lots of secondary wastes. We suggest the removal of I-TEDA by supercritical carbon dioxide with co-solvents. In this experiment, we used a quartz crystal microbalance (QCM) for measuring the removal rate of the I-TEDA. From the experimental results, methanol was found to be the optimum co-solvent, and the optimum conditions such as temperature, pressure, and co-solvent flow rate were obtained. Possibility of using supercritical fluid in the removal of I-TEDA from radioactive activated carbon was also discussed.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.297-304
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• 2023

Domoic acid (DA), a neurotoxin produced naturally by diatoms, is responsible for incidents of amnesic shellfish poisoning. In this study, a modified analytical method was established to determine domoic acid in seafood using solid phase extraction cleanup and optimizing the amount of sample and extraction solvent to reduce interference effects. The modified method using high-performance liquid chromatography with ultraviolet detection was validated using three seafood matrices (mussel, red snow crab, and anchovy) at three concentrations (1, 2, and 4 mg/kg) and compared to the Food Code method. Compared to the Food Code method, the modified method showed better performance in terms of linearity (R²>0.999), detection limit (0.02-0.03 mg/kg), quantification limit (0.05-0.09 mg/kg), intra-/inter-day accuracy (86.2-100.4%), and intra-/inter-day precision (0.2-4.0%). Furthermore, the method was successfully applied for the analysis of 87 seafood samples marketed in Korea, and DA was detected at a low concentration of 140 ㎍/kg in one anchovy sample. These results suggest that the modified method can be used for routine determination of DA in seafood.

• Proceedings of the Korean Society of Life Science Conference
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• 2002.05a
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• pp.17-22
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• 2002

지구상에는 수천종의 버섯류가 자생하고 있어 유전자원으로서의 중요성이 지대할 뿐만 아니라 기능성 식품소재 및 각종 약리 활성을 나타내는 신약개발 소재로도 크게 주목을 받고 있다. 이들 버섯은 균사체의 영양대사로 얻어지는 대사산물이 축적된 자실체의 형태로 나타나는데, 최근에 와서 자실체 및 균사체의 추출물이나 균사체 배양물이 체질개선이나 각종 병의 예방과 치료에 효과가 있는 것으로 밝혀져 건강식품이나 의약품으로서의 용도가 크게 증가하고 있는 실정이다. 특히, 담자균이 생산하는 특정 구조를 갖는 다당류는 오래전부터 종래의 화학요법제와는 달리 숙주내의 면역 기능을 부활하여 소위 면역요법제로서의 항암효과를 나타냄이 알려져왔었다. 현재까지 제약 및 의학적인 방법이 질병의 주된 치료방법으로 이용되어 왔지만 최근에 특정식품의 섭취가 만성질환의 발생을 억제 또는 지연시킨다는 연구 보고가 나오면서부터 만성질환의 치료방법으로서 식이요법을 중요하게 생각하게 되었다. 따라서 새로운 식품소재 및 가공식품의 개발을 통한 성인병 등의 각종 질병예방이 국민보건문제 해결에 필수적이다. 현재 일본 등에서는 표고버섯, 구름버섯 및 치마버섯 유래의 다당체 또는 단백다당체인 lentinan, krestin 또는 PS-K, schizophyllan 및 PSP 등이 실용화되어 높은 가격에 판매되고 있다. 국내에서도 야생 구름버섯 자실체로부터 추출한 단백 다당체인 Copolang(광동제약)이 개발되어 PS-K와 유사하게 암의 치료에 병행 사용되고 있고, 또 강력한 항암활성이 보고된 상황버섯의 균사체 추출물인 단백 다당체가 Mesima-Ex FK(한국신약)라는 상품명으로 암의 치료에 병행 사용되고 있는 것으로 알려지고 있다. 담자균류와 아울러 미생물 유래 다당체는 그 구조와 특성에 있어서 매우 다양함을 지니고 있다. 이러한 미생물 유래 다당류의 공업적 생산과 이용에 대한 연구로서는 Leuconostoc mesenteroides가 생산하는 dextran이 혈장증량제로 개발된 이래 Xanthomonas campestris가 생산하는 pullulan, Zoogloea rgmigera가 생산하는zooglan둥이 대표적인 예로 보고되고 있다. 한편, 미생물 유래 다당류는 구성당, 분자량, 화학적 구조 등과 같은 특성의 차이에 의해 많은 종류가 존재하고 있으며, 다양한 물성 및 유화제, 응고제, gel 형성제, 필름 형성제, 흡착제, 안정제, 접착제 등과 같은 용도로 광범위하게 이용되고 있다. 또한 근래에 들어서는 미생물 유래 다당체가 지니는 항암활성이 확인되어 새로운 의약품으로서의 개발 가능성이 기대된다. 그 밖에도 기존에 알려져 있는 식물 및 해조류 유래의 다당체와는 달리, 발효조를 이용한 연속배양에 의해 공업적 대량 생산이 가능하며, 더욱이 생산된 다당체의 분리 및 회수가 용이하다는 이점을 지니고 있다. 최근에 들어서는 유전공학적 기법을이용한 고생산성 변이균주 및 새로운 기능을 지닌 다당체의 개발에 관한 연구가 보고되고 있는 등 고부가가치를 지닌 새로운 바이오 소재로서의 기능 및 용도 개발에 관한 연구가 활발히 진행되고 있다. 이러한 항암 활성을 나타내는 여러 가지 담자균류중 Agaricus blazei로부터 생산되는 다당체는 고형암 이외에 S형 결장암, 난소암, 유방암, 폐암, 간암 등에 효과가 입증되었고, 천연물질에 의한 암 면역요법으로 각광을 받고 있으며, 항암 및 항virus의 완치율과 저지율에서 현재 여러가지 약효가 있는 버섯중에서도 탁원한 효과가 있는 것으로 증명되고 있다. 이들 다당체는 사이토카인을 생산시켜서 T임파구와 B임파구의 항원 특이적인 면역반응을 활성화시키고, 세포장해성 T세포와 활성화 대식세포의 세포장해 기능을 충진시켜서 암세포를 파괴시킨다. 또한 콜로니 자극인자인 사이토카인을 생산시켜서 면역담당세포의 신생을 촉진시키기도 하며, 암의 화학요법과 방사선 요법으로 저하된 백혈구를 회복시키는 역할을 한다. 따라서 최근의 연구동향은 생산된 다당체의 항암활성을 향상시키고자 하여 배양기간중에 interleukin을 의도적으로 첨가하는 경향이 있다. 이러한 항암 활성을 나타내는 담자균체 유래 다당체는 버섯의 기원에 따라 그 형태에 약간의 차이를 나타내기는 하나 그 기본 형태는 ${\beta}-(1,6)-glucosyl$ 분지를 가진 ${\beta}-(1,3)-glucan$이며, 평균 분자량은 50 ${\sim}$ 200만 정도이다. Agaricus blazei의 원산지인 브라질의 피에다데(Piedade) 지방의 환경조건(산지의 습도는 80%, 낮 기온 $35^{\circ)C$, 밤 기온 $20{\sim}25^{\circ}C$로 대단히 높으며, 정기적으로 열대지방 특유의 소나기가 내리는 지역)에서 볼 수 있듯이 Agaricus blazei의 성장 환경은 매우 까다로운 편이며, 날것으로는 보관이 잘 안되기 때문에 그 재배에 큰 어려움이 있다. 또한, 고체배양에 의해 생산된 버섯 자실체로부터 유기용매 및 열수추출 방법으로 다당체를 생산하는 방법은 균일한 형태의 버섯 자실체를 공급받기가 어렵기 때문에 다당체의 생산 수율이 낮고, 많은 노동력이 요구되는 어려움이 있다. 그러나 액체배양에 의한 다당체 생산의 경우는 고체배양에 의한 다당체 생산에 비해 일정한 조건하에서 배양이 가능하다는 장점이 있으며, 항상 균일한 균사체 및 배양액을 얻을 수 있다. 따라서 원하는 유용물질을 쉽게 획득할 수 있는 장점이 있다.