• Korean Journal of Food Science and Technology
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• v.46 no.1
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• pp.39-43
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• 2014

The antimicrobial activity of Orixa japonica Thunb. leaf extract towards 13 microorganism strains was evaluated. Both methanol (MEex) and 70% ethanol extracts showed antimicrobial activity towards Streptococcus mutans, Bacillus cereus, Staphylococcus aureus, and Pseudomonas aeruginosa. MEex showed a higher antimicrobial activity than the 70% ethanol extract. In addition, the dichloromethane fraction (DCMfr) of the MEex also had an antimicrobial effect against the microorganisms examined. The minimum inhibitory concentrations (MICs) towards S. mutans, B. cereus, S. aureus, and P. aeruginosa were 49.22, 24.61, 49.22, and 49.22 mg/mL, respectively. In contrast, the MICs of the DCMfr tpwards S. mutans, B. cereus, S. aureus, and P. aeruginosa were 3.31, 0.21, 1.7, and 1.7 mg/mL, respectively. The MEex antimicrobial activity was not affected by a 3 h exposures to pH in the range of 3-11 or by temperatures were maintained between $80^{\circ}C-100^{\circ}C$ for 6 h. However, the MEex antimicrobial activity decreased at a heat treatment of $121^{\circ}C$ 1 h.

• The Korean Journal of Pesticide Science
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• v.18 no.2
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• pp.69-78
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• 2014

In the present study, we developed an official individual analytical method for cymoxanil using HPLC/UVD, respectively in different representative crops. Individual analytical methods for these pesticides are not included in the Korea food code. The samples were extracted with acetonitrile, concentrated and partitioned with dichloromethane and saturated sodium chloride solution. For cymoxanil, extracts were concentrated and clean-up through silica gel column chromatography with dicloromethane/acetone (60/40 v/v) and subjected to instrumental analysis. The limit of detection (LOD) for cymoxanil were 0.1 ng and 1 ng respectively and limit of quantitation (LOQ) were 0.02 mg/kg. Recoveries for cymoxail ranged from 79.6~107.6% respectively, at fortification level of 0.02 mg/kg (LOQ), 0.2 mg/kg (10 LOQ) and 1.0 mg/kg (50 LOQ) and the coefficient of variation (CV) was less than 10%, regardless of sample types. These results were further confirmed with LC/MS. The proposed simultaneous analysis method is reproducible and sensitive enough to determine the residues of cymoxanil in the agricultural commodities. According to the validation data and performance characteristics and high sample throughput, the proposed method is suitable for routine application.

• Analytical Science and Technology
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• v.16 no.1
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• pp.48-58
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• 2003

The effects of physico-chemical properties of soils on PCBs analysis in Korea was studied Three kinds of extraction solvents(toluene, acetone:hexane, dichloromethane) was selected to apply three different soils. The silicagel, florisil and alumina column cleanup also performed to compare the elution patterns, and three different methods (EPA, Japan, Proposed method in this study) of 62 PCBs also compared the individual peaks recoveries. The solvent average recovery was surveyed the order of toluene, acetone:hexane, dichloromethane as 77.94%, 58.59%, 54.20% for soil A, 53.65%, 80.32%, 68.27% for soil B and 44.52%, 60.35%, 56.36% for soil C, respectively. The average recovery was depended on the soil characters. The highest recoveries of each soil were obtained the toluene for soil A, acetone:hexane for soil B and C. However, the coplanar PCBs was obtained the highest recovery with dichloromethane. Thus, to select the solvent for the analysis of PCBs in solid, the selected compounds have to consider to get good result. The silicagel, florisil, alumina I and alumina II column cleanup process were surveyed the range of 38.73%~98.26%, and the higher chlorinated compounds was obtained the lower recovery compared to the low chlorinated compounds, generally. This results are also consistent with the coplanar PCBs isomers. The compared results of three different countries were obtained the 37.15% for USA, 45.92% for Japan and 44.46% for proposed method in this study.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.303-310
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• 2005

This study was performed to examine analytical method of a quinolone compound, oxolinic acid in paddy soil by HPLC coupled with UV detector. Two types of soil texture in different regions were used for this experiment. Oxolinic acid was extracted by a 4 M-KOH : MeOH(1 : 3, v/v) mixtures and acidified followed by liquid-liquid partitioning in dichloromethane. Dichlormethane layer was dehydrated, evaporated and analyzed by HPLC (262 nm). Retention time was 10.2 min. The standard calibration curve of oxolinic acid showed linearity ($r^2>0.999^{**}$, y=378.99x+135.08) in the range of $1{\sim}40$ ng. The mean recoveries, evaluated from fortified soil samples at two concentration levels of 0.2 mg/kg and 1.0 mg/kg, were $90.9{\pm}4.52%$(C.V. 4.97%) and $95.0{\pm}0.23%$(C.V. 0.24%) for soil 1 and $92.2{\pm}1.15%$(C.V. 1.25%) and $93.1{\pm}0.31%$ (C.V. 0.33%) for soil 2, respectively The detection limits of two types of soils were same as 0.05 ppm. Overall, the present analytical method of oxolinic acid by HPLC coupled with UV detector seems to be used reasonably.

• Korean journal of food and cookery science
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• v.21 no.6 s.90
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• pp.759-768
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• 2005

This study was performed to determine the antioxidative effect of the hexane, dichloromethane, ethylacetate, butanol and water fractions of Ganoderma lucidum extracts on the inhibition of malondialdehyde(MDA) and bovine serum albumin(BSA) conjugation reaction, the inhibition of lipid peroxidation and the scavenging effect on 1,1-diphenyl-2-picryl-hydrazyl(DPPH) radical, the antimutagenic capacity as measured by the Ames test and the inhibitory effect on cancer cell. Ganoderma lucidum is believed to have possible antioxidative capacities, although the results have varied according to the assay method. The most effective antioxidative capacity was inhibition of lipid peroxidation. Among the five fractions, water fraction showed strong inhibition rates on MDA & BSA conjugation reaction, and ethylacetate fractions showed the most effective inhibition rate on lipid peroxidation and scavenging effect on DPPH radical. The indirect and direct antimutagenic effects of ethanol extracts of Ganoderma lucidum were examined by Ames test using Salmonella typhimurium TA98 and TA100. Among the samples, the water fraction did not have any antimutagenic effect. The inhibition rates on mutagenicity in the presence of 2.5 mg/plate were nearly $100\%$ for Salmonella typhimurium TA98 and TA100 except the hexane fraction of the direct mutagenicity mediated by 2-Nitrofluorene in Salmonella typimurium TA98($64.69\%$). Under the 2.5 mg/plate concentration, the inhibitory effects of hexane and dichloromethane fraction were superior to that of the other fractions on the direct mutagenicity for Salmonella typhimurium TA100 and indirect mutagenicity for Salmonella typhimurium TA98 and TA100. The inhibitory effect of Ganoderma lucidum extracts on cell proliferation in HeLa and MCF-7 was investigated by U test. The dichloromethane fraction showed highly antiproliferative effect in HeLa and MCF-7($IC_{50}$: 0.122 mg/mL, 0.272 mg/mL, respectively) cells while the water faction had a weak inhibitory effect($IC_{50}$: 0.691 mg/mL, 10.919 mg/mL respectively). These results suggest that Ganoderma lucidum may have antioxidative, antimutagenic and anticancer capacities and may be a candidate of the prevention and dietetic treatment of chronic diseases and the development of antioxidative, antimutagenic and anticancer functional food.

• Journal of Soil and Groundwater Environment
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• v.19 no.6
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• pp.49-58
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• 2014

This study was implemented as a part of the experiment to develop two kinds of soil-based Benzo[a]pyrene (BaP) proficiency testing materials (PTMs) for soil analysis. A test was carried out for the check of solubility of the reference material (high purity reagent) using several solvents. Another test was also conducted for the evaluation of homogeneity and stability of two kinds of candidate soil reference materials. The test analysis of BaP in terms of the candidate materials was conducted according to the Standard Soil Analytical Methods by Ministry of Environment. Dissolution of the reference material was shown to vary depending on solvent type and was higher in the order of Dichloromethane > Acetone > Acetone/MeOH (9 : 1) > N-hexane. In addition, the slope on calibration curve for BaP standard solutions was largest on BaP standard solutions prepared with dichloromethane of the tested solvents. Such tendency appeared egually in the commercial BaP standard solution. Therefore, it is thought to be reasonable to use dichloromethane as the solvent in case of the standard stock solution that is used for the measurement of BaP concentration in soil. ISO 13528 and IUPAC protocol were used for verification of homogeneity on the two kinds of soil candidate materials, Both candidate materials were sufficiently homogeneous. Stability assessment of the two candidate materials was made according to ISO Guide 35 and the result showed that both batches did not have any long-term and short term stability issues that might occur during shipping. However, monitoring results of BaP concentration in soil showed that BaP concentration of the two batches measured at 15 days after the sample preparation was reduced by about 24~37% compared with that of the samples measured on 0 day of the sample preparation. Identification was done with several treatments such as irradiation and sterilization etc. The major cause was shown to be irradiation to the samples.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.31 no.4
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• pp.317-330
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• 2021

Objectives: By law, companies in Korea must periodically measure workers' exposure to harmful chemicals (the system is called the Work Environment Monitoring Program (WMP)[a]) and report the results to the government. The government also measures exposure to monitor the WMP's reliability (called Reliability Assessment (RA) for WMP[b]). The issue is that measured data from these two sources are so different that the objectivity of WMP needs to be confirmed by comparing the results using the European Centre for Ecotoxicology and Toxicology of Chemicals' Targeted Risk Assessment (ECETOC TRA). Methods: Step 1: Data collection from WMP reports submitted by companies (n=586) and RA for WMP written by the government (n=33). Step 2: Data Standardization by key information included. Step 3: Data conversion to input-variables required to run the ECETOC TRA model, and run the model with specific data (n=514) which meet the predetermined exposure scenario. Step 4: Statistical data analysis by process category (PROC) and ventilation type from each source ([A] and [B]). Step 5: Additional analysis of any unexpected results. Results: The process categories of the production and handling of Dichloromethane were classified into 12 PROCs, and ten of them were selected to run ECETOC TRA. Modeled values tended to be higher than measured values from both sources. For the measured values from WMP, RCR distribution by PROC was narrow (0.197-0.267, 95% CI) and did not have a relationship with ventilation type, which differs from the tendency of the modeling result. Meanwhile, the measured values from RA for WMP were relatively widely distributed (0.301-1.177, 95% CI) by PROC. In particular PROCs (13,19) were high enough to exceed 1. Also, they become low with better ventilation types and appear differently depending on the ventilation type, similar to the model result. Conclusions: This study revealed that ECETOC TRA might have the potential to serve as a screening tool for exposure assessment and to be used as assistive method for WMP to estimate exposure. Further empirical study is required to confirm its availability as a screening tool.

• Journal of Environmental Health Sciences
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• v.50 no.3
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• pp.221-228
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• 2024

Background: Social interest is increasing due to frequent accidents caused by chemicals in the electronics industry. Objectives: The purpose of this study is to present a management plan by evaluating the exposure characteristics of dichloromethane (DCM), trichloromethane (TCM), and tetramethyl ammonium hydroxide (TMAH), which are high-risk substances to which people may be exposed in the electronics industry in South Korea. Methods: To investigate the handling companies and status of the hazardous chemicals DCM, TCM, and TMAH, the handling status of the three substances was classified based on electronics industry-related codes from the 2019 Work Environment Survey (Chemical Handling and Manufacturing) data with work environment measurement results for five years. Results: DCM, TCM, and TMAH are commonly used as cleaning agents in the electronics industry. For DCM, it was found that all work environment measurement results from 2018 to 2021 but not 2022 exceeded the exposure standard. Conclusions: Identifying the distribution channels of hazardous chemicals is an intervention point that can reduce exposure to hazardous chemicals. It requires management through tracking systems such as unique verification numbers at the import and manufacturing stages, and proper cultivation of and related support for handling chemicals by business managers.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.253-254
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• 2003

구미시 산단지역은 반도체, LCD, 브라운관, 정보통신기기 등 첨단전자 정보통신산업을 위주로 형성되어 있으며, 섬유와 기타 합성수지 산업도 위치하고 있다. 이러한 산업 구조로 인해 전자산업에서는 세척제로 Trichloroethylene과 Dichloromethane등이 사용되며, 섬유와 합성수지 산업에서는 Toluene과 같은 유기용제가 많이 사용되고 있다. 이에 본 연구에서는 전자산업을 위주로 형성된 구미 산단지역의 대기중 휘발성유기화합물(이하 VOCs)의 농도를 여름과 겨울철로 나누어 측정ㆍ평가하여, 구미지역 유해오염도 개선을 위한 기초자료를 제시함을 목적으로 하였다. (중략)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.235.2-236
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• 2002

The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring mode followed by three work-up methods for comparison: EPA method, isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in water samples were extracted with dichloromethane. (omitted)