• Resources Recycling
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• v.7 no.1
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• pp.14-19
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• 1998

Tile pl~ysimchemical properties of residual or unburned carbon obtaincd from fly ash were mestigated. The carbon-enrichcd samples were extracted from fly ash by flotalion mcthod. Tnz carbon content and chemical compos~lion of t b recovered carbon sample were analyzed. The ash in the carbon sample was also examined. The unburned carbon characterization included measurement oE sire distibution, sudace area, crystal shuchlre md density.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 1998.04a
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• pp.71-71
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• 1998

수산용 향균제로 널리 사용되고 있는 옥소린산의 잔류량의 전북지역에서 시판중인 뱀장어 근육조직에서 측정하였다. 후배부 근육중의 옥소린산 잔류량은 시료에 따라 많은 차이가 있었으며 32%의 시료에서는 검출되지 않았다. 옥소린산이 검출된 시료중 16%에서는 그 농도가 0.1pm 이상이었다. 중요 장기중이 옥소린산 농도는 신장>간장>혈장>근육의 순이었다. 근육중의 옥소린산은 10분 가열에 의해 거의 감소되지 않았으며 30분 가열에 의해서는 원래 농도의 50%수준으로 감소하였으나 30분 가열 후의 시료는 심하게 탄화되었다. 고용량의 옥소린산을 실험실적으로 뱀장어에 투여하여 얻은 근육중의 농도나 수용액중의 옥소린산이 가열에 의해 파괴되는 경향을 검토함으로써 옥소린산의 열안정성이 확인되었다. 이 연구 결과는 뱀장어 소비자를 옥소린산 섭취로 부터 보호할 수 있는 규제의 강화가 필요함을 시사한다.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.235-240
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• 2010

In order to elucidate residual characteristics of pesticides in garlic by drying, azoxystrobin and flutolanil used for garlic were treated to the garlic by dipping for 1 and 5 min into their standard diluents and then the garlic was dried with a freeze-drier. The test pesticides were analyzed with a GLC-ECD/NPD. Recoveries of the pesticides ranged from 81.96 to 98.18%. Amount of azoxystrobin and flutolanil in fresh garlic were 0.34 and 1.18 mg/kg in case of dipping for 1 min. and 0.44 and 2.15 mg/kg in case of dipping for 5 min., respectively. Also, amount of azoxystrobin and flutolanil in dried garlic were 0.80 and 4.51 mg/kg in case of dipping for 1 min. and 1.03, 5.28 mg/kg in case of dipping for 5 minute, respectively, representing that concentration of the test pesticides in garlic were increased by drying. In case of dipping for 1 and 5 min., processing factors of azoxystrobin were 2.35 and 3.34 and those of flutolanil were 1.19 and 1.17, respectively. Reduction factors of the pesticides in garlic were range from 0.94 to 0.97, indicating that few amounts of the test pesticides in garlic were dissipated by freeze-drying.

• The Korean Journal of Pesticide Science
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• v.21 no.1
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• pp.75-83
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• 2017

The single residue analytical method was developed for determining fungicide pencycuron residues in various agricultural commodities with high-performance liquid chromatography (HPLC). Pencycuron residue was extracted with acetone from representative crops such as Korean cabbage, apple, brown rice and green pepper. After ethyl acetate/n-hexane partition and subsequent clean-up with silica gel chromatography, pencycuron residue was quantified by reversed phase HPLC with UV detection at 240 nm. The suspected residue of pencycuron was confirmed using selected-ion monitoring (SIM) LC/mass spectrometry (MS). Instrumental limit of quantitation (ILOQ) and method LOQ (MLOQ) were set at 2 ng and 0.02 mg/kg, respectively. Overall recoveries of pencycuron from different crop samples fortified at three levels (MLOQ, 10MLOQ, 100MLOQ) were 72~108%. This proposed method could be useful as official analytical method for quantification of pencycuron residues in agricultural commodities.

• Journal of Food Hygiene and Safety
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• v.6 no.2
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• pp.83-87
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• 1991

Beef, pork and chicken on the market were analyzed for determination of tetracyclines residue and decomposition of tetracyclines by heating were studied. The content of oxytetracycline was trace in chicken A, 0.09 mg/kg in C and trace in beef C, pork A and B, but in the other samples was not detected oxytetracycline. Chlortetracycline residue was 0.14, 0.02 and 0.01 mg/kg in chicken A, C and beef B respectively. In HPLC analysis, two peaks of 8.1 and 9.0 min of retention time were found from beef and pork and expected to be component of meat, and because of same retention time, the one of 9.0 min interrupted determination of tetracycline. But those were not found in chicken, therefore the residue was 0.01 mg/kg in sample A. The residue were degradated rapidly by heating of roast, but slightly by that of boiling.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.185-194
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• 2015

This study was performed to establish a single residue analytical method for determining fungicide carpropamid residues in various agricultural commodities. Korean cabbage, apple, brown rice and green pepper were selected as representative crops. Samples were homogenized, extracted with acetone and purified by liquid-liquid partition and Florisil column chromatography. Carpropamid residues were analyzed at 220 nm with reversed phase HPLC equipped octylsilyl and octadecylsilyl column and confirmed using mass spectrometry. ILOQ (Instrumental limit of quantitation) of carpropamid was 2 ng and MLOQ (Method LOQ) was 0.02 mg/kg. Mean recoveries from four kinds of crop samples fortified at three levels (MLOQ, 10LOQ, 100LOQ) in triplicate were in the range of 84~112%. Relative standard deviations of the analytical method were all less than 10%, irrespective of crop types.

• Applied Biological Chemistry
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• v.23 no.1
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• pp.58-63
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• 1980

Present investigation is undertaken to evaluate residues of organochlorine pesticides and PCBs in river sediments and cultivated soils by GLC. Main sampling areas chosen were three industrial estates, Suwon, Iri and Kumi. Samples consist of river sediments and cultivated soils, in Suwon, Iri and Chilgok, which are likely to be accumulated with PCBs from nearby factories. Organochlorine pesticide residues were found in all sediments and soil samples while no PCBs residue was detected in all samples analyzed. The pesticide residues were greatest in the Suwon and least in Chilgok soils. p,p'-DDT and BHC isomers $({\alpha}-,\;and\;{\gamma}-)$ were found in all soil samples. p,p'-DDT, at the range of 0.006-0.840 ppm, was the most abundant residues among organochlorine insecticides.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.291-292
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• 2003

잔류성 유기오염물질(POPs; Persistent Organic Pollutants)은 환경 내에서 분해가 느려 잔류성이 높고, 생체 지질에 축적되는 독성이 강한 특성이 있다. 따라서 스톡홀름 협약(2001년 5월 23일)에서 12종의 POPs 물질에 대해 국제적 사용금지 및 관리가 결정되었다. POPs는 대부분 반휘발성(semi-volatile) 이어서 대기 중 장거리 이동되어 배출지와 다른 곳에 침적되는 것이 보고되어있다. 이러한 물질들의 대기 중 잔류량과 기체상과 입자상의 분포 특성을 살펴서 환경 내 이동성을 파악하는 것은 인체위해성 수준을 알아내는데 중요한 자료이다. (중략)

• The Korean Journal of Nuclear Medicine
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• v.39 no.4
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• pp.257-262
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• 2005

Purpose: Gastric emptying scan (GES) is usually acquired up to 2 hours. Our study investigated whether a fraction of meal-retention in the stomach at 120 minutes (FR120) was predicted from the data measured for 90 minutes by using non-linear curve fitting. We aimed at saving the delayed imaging by utilizing mathematical models. Materials and Methods: Ninety-six patients underwent GES immediately after taking a boiled egg with 74 MBq (2 mCi) Tc-99m DTPA. The patients were divided into Group I ($T_{1/2}\;{\leq}90\;min$) and Group II ($90\;min). Group I (n=51) had 21 men and 30 women, and Group II (n=45) 15 men and 30 women. There was no significant difference in age and sex between the two groups. Simple exponential, power exponential, and modified power exponential curves were acquired from the measured fraction of meal-retention at each time (0, 15, 30, 45, 60, 75, and 90 min) by non-linear curve fitting ($MATLAB^{\circledR}$ 5.3) and another simple exponential fitting was performed on the fractions at late times (60, 75, and 90 min). A predicted FR120 was calculated from the acquired functional formulas. A correlation coefficient between the measured FR120 and the predicted FR120 was computed ($MedCalc^{\circledR}$ 6.0). Results: Correlation coefficients(r) between the measured FR120 and the predicted FR120 of each mathematical functions were as follows: simple exponential function (Group I: 0.8558, Group II: 0.5982, p<0.0001), power exponential function (Group I: 0.8755, Group II: 0.6008, p<0.0001), modified power exponential function (Group I: 0.8892, Group II: 0.5882, p<0.0001), and simple exponential function at the late times(Group I: 0.9085, Group II: 0.6832, p<0.0001). In all the fitting models, the predicted FR120 were significantly correlated with the measured FR120 in Group I but not in Group II. There was no statistically significant difference in correlation among the 4 mathematical models. Conclusion: In the cases with $T_{1/2}\;{\leq}90\;min$, the predicted FR120 is significantly correlated with the measured FR120. Therefore, FR120 can be predicted from the data measured for 90 minutes by using non-linear curve fitting, saving the delayed imaging after 90 minutes when $T_{1/2}\;{\leq}90\;min$ is ascertained.

• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.83-88
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• 1982

Residues of some organochlorine pesticides $({\alpha}-BHC,\; {\gamma}-BHC,$ heptachlor, aldrin, heptachlor epoxide, dieldrin, p,p'-DDD, p,p'-DDT) in the cultivating soils (53 samples) were evaluated in the suburbs of Gwangju-City, Jeollanam-Do. Results obtained are summarized as follows. 1) Seven organochlorine pesticides were detected in more than 60% of the sample soils except dieldrin. In particular, ${\alpha}-BHC$ was detected in almost all soil samples and residue level of p,p'-DDT was higher than that of the others. 2) Detection frequencies and residue levels of up-land soil were higher than those of paddy soil. 3) There was no difference in the organochlorine residue levels between land-readjusted paddy soil and natural paddy soil.