• Proceedings of the PSK Conference
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• 2003.04a
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• pp.280.3-281
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• 2003

A high-performance liquid chromatographic method for the simultaneous quantitative analysis of DMDM hydantoin, sorbic acid, phenoxy ethanol in cosmetics was studied by using a X-terra C18 column and 0.75mM KH2PO4 in 0.85％ sulfuric acid and methanol mixture(7:3) at 214nm. Calibration curves were found to be linear in the 20-100$\mu\textrm{g}$/mL range (DMDM hydantoin), 50-250$\mu\textrm{g}$/mL range (sorbic acid) and 10-50$\mu\textrm{g}$/mL range (phenoxy ethanol). The result of recovery test were 96.6％ - 104.2％. This HPLC method can be applied quality control of cosmetics.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.527-527
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• 2003

A high-performance liquid chromatographic method for the simultaneous quantitative analysis of DMDM hydantoin, sorbic acid, phenoxy ethanol in cosmetics was studied by using a X-terra C$\sub$18/ column and 0.75mM KH$_2$PO$_4$ in 0.85% sulfuric acid and methanol mixture(7:3) at 214nm. Calibration curves were found to be linear in the 20-100 $\mu\textrm{g}$/mL range (DMDM hydantoin), 50-250 $\mu\textrm{g}$/mL range (sorbic acid) and 10-50 $\mu\textrm{g}$/mL range (phenoxy ethanol). The result of recovery test were 96.6% ∼ 104.2%. This HPLC method can be applied quality control of cosmetics.

• Korean Journal of Environmental Agriculture
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• v.42 no.1
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• pp.71-81
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• 2023

An accurate and easy-to-use analytical method for determining isocycloseram and its metabolites (SYN549431 and SYN548569) residue is necessary in various food matrixes. Additionally, this method should satisfy domestic and international guidelines (Ministry of Food and Drug Safety and Codex Alimentarius Commission CAC/GL 40). Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) was used to determine the isocycloseram and its metabolites residue in foods. To determine the residue and its metabolites, a sample was extracted with 20 mL of 0.1% formic acid in acetonitrile, 4 g magnesium sulfate anhydrous and 1 g sodium chloride and centrifuged (4,700 G, 10 min, 4℃). To remove the interferences and moisture, d-SPE cartridge was performed before LC-MS/MS analysis with C₁₈ column. To verify the method, a total of five agricultural commodities (hulled rice, potato, soybean, mandarin, and red pepper) were used as a representative group. The matrix-matched calibration curves were confirmed with coefficients of determination (R²) ≥ 0.99 at a calibration range of 0.001-0.05 mg/kg. The limits of detection and quantification were 0.003 and 0.01 mg/kg, respectively. Mean average recoveries were 71.5-109.8% and precision was less than 10% for all five samples. In addition, inter-laboratory validation testing revealed that average recovery was 75.4-107.0% and the coefficient of variation (CV) was below 19.4%. The method is suitable for MFDS, CODEX, and EU guideline for residue analysis. Thus, this method can be useful for determining the residue in various food matrixes in routine analysis.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.136-136
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• 2002

Polycyclic aromatic hydrocarbons(PAHs) vary in their carcinogenic potencies. The more potent PAHs carcinogens are 3-methylcholantheren and 7, 12- dimethyl benzo(a)anthracene, while dibenzo(a, c)anthracene has very little carcinogenic activity. Risk assessment of chemical mixture containing various congeners which toxic potency are each different, are conducted using toxic equivalency factors(TEFs).(omitted)

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.383-389
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• 2010

The aim of this study was to determine the methylmercury (MeHg) levels in abyssal fish species. The MeHg in the fishes was extracted with hydrochloric acid and toluene and then purified using an L-cysteine solution. The extract was analyzed with a gas chromatography-electron capture detector (GC-${\mu}ECD$) with a thermon Hg-capillary column. The detection limit and the recovery of the method were 0.002 and 84.2-98.5% (mean, 93.4%), respectively. The MeHg content in 492 abyssal fishes ranged from 0.037 to 2.009 mg/kg. The levels of MeHg [range, mg/kg (mean)] were significantly dependent on fish species and presented as the following; 0.157-2.009 (0.546) in Scalloped hammerhead shark, 0.211-0.878 (0.501) in Blue shark, 0.121-0.993 (0.482) in Spiny dogfish, 0.243-0.658 (0.397) in Salmon shark, 0.074-1.958 (0.353) in Blacktip shark, 0.038-0.807 (0.302) in Southern hake, 0.099-0.511 (0.300) in Scorpion fish, and 0.037-0.133 (0.067) in Ling. The monitoring results showed that the estimated weekly intake of MeHg from sharks, Southern hake, and Ling were lower than the provisional tolerable weekly intake recommended by the Joint FAO/WHO expert committee on food additives.

• YAKHAK HOEJI
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• v.58 no.4
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• pp.255-261
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• 2014

Poly-pharmacy has been on the rise because of aging of population and chronic disease. Most of drug metabolism happens in the liver by CYP isozymes and the metabolism by CYP450 enzymes. The Cytochrome P450 (CYP) is a superfamily of enzymes that catalyzes the oxidations of many endogenous and exogenous compounds. Primary human Hepatocytes (HH) are considered as the gold standard model for In vitro drug interaction studies. However, there are several limitations (cost, limited life span) for using HH cells. HepaRG cells are being used as a possible alternative. HepaRG cells were cultured in William E medium containing the positive control inducers (1A2: 10, 25, 50 ${\mu}M$ omeprazole, 2C9 and 2C19: 10 ${\mu}M$ rifampin, 3A4: 10, 25, 50 ${\mu}M$ rifampin) at $37^{\circ}C$, 5 % $CO_2$ in a humidified atmosphere. This study was to evaluate the induction of CYP isozymes (1A2, 2C9, 2C19 and 3A4) using LC-MS/MS. We evaluated the potential induction ability of Bosentan, as a drug of pulmonary artery hypertension, in HepaRG cells. For reference, dose of the Bosentan is determined to the basis of the $C_{max}$ (835 mg/ml) value. The enzyme activity demonstrated that CYP2C9 and 3A4 were induced up to 20 times by Bosentan. Like as In vivo, the enzyme activity of CYP2C9 and CYP3A4 is significantly induced in a dose-dependent by Bosentan.

• YAKHAK HOEJI
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• v.55 no.4
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• pp.284-288
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• 2011

The test method for biologics of lot release system is based on 'Test procedure and specification for biological products,' generally, thimerosal content is measured by chemical analysis using O.D. In this study, the comparative analysis was carried out using the gold amalgamation method for thimerosal content was compared to the existing methods, which are described above. The gold amalgamation method, which uses atomic absorption spectrophotometry, was meets all the method validation acceptance criteria. It is considered to be proper as the assay and identification test for thimerosal. In this study, the comparative analysis was performed three times. As a result, gold amalgamation method is more convenient and easy to perform as this assay doesn't have pre-treatment procedure. Also this assay showed good precision and reproducibility compared to the conventional method. Therefore, it is appropriate to alternate the assay method of thimerosal from the conventional chemical analysis to gold amalgamation method to improve the credibility of lot release system and the quality control of biologics, by standardizing test method.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.67-70
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• 2001

• Journal of Biomedical Engineering Research
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• v.31 no.4
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• pp.280-284
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• 2010

Approvals of medical device increase every year as industry of medical device grows. Therefore KFDA keeps trying to improve approval systems. However, the firms of medical device are in trouble due to regulation amendment, a firm of small size, exchange of the person in charge. The staffs of KFDA increase their work load because applicants of approval of medical device aren't used to writing of document. Therefore the firm of medical device in business have a long term. KFDA develops eight guidance document item by item for one-step evaluation and approval for Medical Devices because applicants of approval of medical device write documents easily. KFDA reviewer can carry on quick reviewing in use of this eight guidances. This guidance are improved on satisfaction of applicants of approval of medical device.

• Korean Journal of Environmental Agriculture
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• v.40 no.2
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• pp.108-117
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• 2021

BACKGROUND: Dichlobentiazox is a newly registered pesticide in Korea as a triazole fungicide and requires establishment of an official analysis method for the safety management. Therefore, the aim of this study was to determine the residual analysis method of dichlobentiazox for the five representative agricultural products. METHODS AND RESULTS: Three QuEChERS methods were applied to establish the extraction method, and the EN method was finally selected through the recovery test. In addition, various adsorbent agents were applied to establish the clean-up method. As a result, it was found that the recovery of the tested pesticide was reduced when using the d-SPE method with PSA and GCB, but C₁₈ showed an excellent recovery. Therefore this method was established as the final analysis method. For the analysis, LC-MS/MS was used with consideration of the selectivity and sensitivity of the target pesticide and was operated in MRM mode. The results of the recovery test using the established analysis method and inter laboratory validation showed a valid range of 70-120%, with standard deviation and coefficient of variation of less than 3.0% and 11.6%, respectively. CONCLUSION: Dichlobentiazox could be analyzed with a modified QuEChERS method, and the method determined would be widely available to ensure the safety of residual pesticides in Korea.