• The Korean Journal of Pesticide Science
• /
• v.15 no.2
• /
• pp.149-159
• /
• 2011

Bentazone is benzothiadiazole group herbicide, and used to foliage treatment. This herbicide have already been widely used for cereals and vegetables planting in worldwide. This experiment was conducted to establish a determination method for bentazone residue in crops using HPLC-UVD/MS. Bentazone residue was extracted with acetone (adjusted pH 1 with phosphoric acid) from representative samples of five raw products which comprised hulled rice, soybean, apple, green pepper, and Chinese cabbage. The extract was diluted with saline water, and dichloromethane partition was followed to recover bentazone from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The bentazone was quantitated by HPLC with UVD, using a YMC ODS AM 303 ($4.6{\times}250$ mm) column. The crops were fortified with bentazone at 3 levels per crop. Mean recovery ratio were ranged from 82.0% for a 0.2 mg/kg in apple to 97.9% for a 0.02 mg/kg in Chinese cabbage. The coefficients of variation were ranged from 0.5% for a 0.02 mg/kg in soybean to 9.7% for a 0.02 mg/kg in Chinese cabbage. Quantitative limit of bentazone was 0.02 mg/kg in representative five crop samples. A LC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of bentazone in agricultural commodities.

• The Korean Journal of Pesticide Science
• /
• v.15 no.2
• /
• pp.125-133
• /
• 2011

Ametryn is used in USA, China, and Japan, but not introduced in Korea yet. So, MRL (Maximum Residue Level), and analytical method of ametryn were not establishment in Korea. Therefore, this experiment was conducted to establish a determination method for ametryn residue in crops using HPLC-UVD/MS. Ametryn residue was extracted with acetone from representative samples of five raw products which comprised hulled rice, soybean, apple, green pepper, and Chinese cabbage. The extract was diluted with saline water, and dichloromethane partition was followed to recover ametryn from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The ametryn was quantitated by HPLC with UVD, using a Tosoh ODS 120T ($4.6{\times}250$ mm) column. The crops were fortified with ametryn at 2 levels per crop. Mean recovery ratio were ranged from 83.7% for a 0.2 mg/kg in soybean to 91.1% for a 1.0 mg/kg in hulled rice. The coefficients of variation were ranged from 1.2% for a 1.0 mg/kg in hulled rice to 3.6% for a 1.0 mg/kg in soybean. Quantitative limit of amatryn was 0.02 mg/kg in representative 5 crop samples. A LC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of ametryne in agricultural commodities.

• The Korean Journal of Pesticide Science
• /
• v.13 no.3
• /
• pp.133-147
• /
• 2009

In order to develop the simultaneous analytical method for pesticide residues which ones in soil are rapidly and inexpensively measured by, many analytical methods for individual pesticide residue and several methods for multi-pesticide residues in agricultural commodities and food were reviewed. Various gas chromatographic conditions and pre-treatment procedures were intensively investigated and modified. And then new optimum procedure was established and its proficiency was validated. The response on detectors of simultaneous determination of 180 pesticides out of pesticides used in Korea was tested. The number of pesticides that their limits of detection (LOD) equal or lower than $0.05\;mg\;kg^{-1}$ were 137 pesticides on ECD, 170 pesticides on NPD and 179 pesticides on ECD/NPD integrated. The retention times of most pesticides ranged appropriately between 10 minutes and 40 minutes in the proposed chromatographic conditions. But about 90 pesticides eluded between 20 minutes and 30 minutes and so they were not resolved enough. In partition with dichloromethane, ethyl acetate/hexane (1:1) and ethyl acetate, number of pesticides whose extraction efficiency ranged from 70% to 120%, were 163, 154 and 147, respectively.

• 대한위암학회:학술대회논문집
• /
• 2002.04a
• /
• pp.9-17
• /
• 2002

위의 parietal cell 혹은 대식세포와 유사한 세포 내부에서 H. pylori가 발견된다는 보고가 있기는 하나 일반적으로 H. pylori는 Shigella와 같은 침습성 세균은 아닌 것으로 알려져 있다. 그럼에도 불구하고 H. pylori에 감염된 위점막에는 많은 수의 호중구를 위시한 염증세포의 침윤이 관찰되는데 H. pylori가 위상피세포에 부착 할 경우 위상피세포를 자극하여 interleukin-8을 위시한 cytokine 을 발현케하고 이에 의하여 호중구 등의 염증세포가 몰려들게 된다. 한편 고유층에 몰려든 호중구에서는 다시 interleukin-8을 위시한 일련의 호중구 활성화 chemokine을 분비하여 염증반응을 증폭해 나갈 것이다. 호중구에서 발현되는 myeloperoxidase나 활성 산소 등도 위점막의 조직 손상에 기여할 것이다. 위상피세포를 덮고 있는 점액층은 위상피세포를 보호한다고 알려져 있으나 H. pylori 감염의 경우 점액층에 의하여 H. pylori의 운동성이 증가하고 이것이 위상피세포로부터의 cytokine 발현을 자극하여 염증반응을 증폭하는데 관여할 가능성도 있다. H. pylori는 위상피세포에 대하여 apoptosis를 유도함과 동시에 고유층에 몰려든 호중구에 대하여는 apoptosis를 억제케하여 궁극적으로 염증반응을 증폭 및 지속시켜 나가는 쪽으로 작용한다. 한편 H. pylori는 위상피세포로부터 COX-2의 발현을 증가시키는데 이는 위상피세포의 apoptosis를 억제하는 방향으로 작용한다. 이외에 H. pylori의 urease에 의하여 발생한 암모니아나 H. pylori 자신이 분비하는 세포독소가 세포 손상을 유발할 가능성도 있다. 상술한 여러 독성 인자들 중 어느 하나가 단독으로 작용하기보다는 여러 인자가 같이 동시에 또는 시차를 두고 작용할 가능성이 많다고 생각된다.(\gamma-FeOOH)$, 침철광$(\alpha-FeOOH)$, 적금광$(\beta-FeOOH)$, 그리고 자철광$(Fe_3O_4)$이다. 인위적 부식에서는 전부 인철광의 부식물이 생성되었고 자연적 부식에서는 모두 침철광의 부식물이 생성되었다. 특히 철제 표면에 자연적으로 생성된 공식 녹을 XRD 분석한 결과 적금광으로 동정되었다. 이런 모든 시편들을 각 탈염방법에 따라 탈염처리한 후 XRD와 SEM-EDS으로 분석한 결과 인철광과 침철광은 어떠한 변화도 보이지 않았고, 다만 적금광으로 동정된 시편만이 잔존하지 않았다. 철기 제작별 $Cl^-$ 이온 추출량과 탈염효과에 대한 비교 실험은 이온 크로마토그래피 분석 결과와 마찬가지로 단조 철제유물이 주조 철제보다 $Cl^-$ 이온을 많이 가지고 있었으며, 탈염 처리 후에는 $Cl^-$ 이온은 전혀 발견되지 않았다. 이상의 결과 $K_2CO_3$와 Sodium 용액은 탈염처리에서 가장 적합한 탈염처리 용액으로 알수가 있었으며 특히 어떠한 탈염 용액으로 유물을 처리한다 해도 철제유물에 생성된 부식물은 제거되지 않는다는 것을 알게 되었다. 따라서 보존처리자는 유물 표면의 부식 상태만을 보고 처리하기 보다는 철기제작물로 고려하여 처리하는 것이 필요하다. 또한 금속에 부식을 야기시키는 $Cl^-$ 이온과 부식물을 완전하게 제거하여 탈염처리를 하는 것이 유물 부식을 최대한 지연시킬 수 있는 것이라 생각된다.TEX>$88\%$)였다.(P=0.063). 결론: 본 연구에서는 MTHFR C/T & T/T 유전자 다형성이 위암의 발생과 그 위치에 대해 관련이 있는 것으로 여겨지고, 흡연력, 음주력과는 관련이 없는 것으로 여겨진다.험이

• Journal of Life Science
• /
• v.20 no.2
• /
• pp.183-189
• /
• 2010

A fibrinolytic enzyme producing Bacillus sp. J-19 was isolated from the popular Korean seasoning, pickled anchovy. The fibrinolytic enzyme was purified to homogeneity by chromatographic methods including ethanol precipitation and gel-filtration using Sephadex G-50. Compared to the crude enzyme extract, the specific activity of the enzyme increased 1021-fold with a recovery of 23%. The purified enzyme was estimated to be approximately 45 kDa by SDS-PAGE. Especially, the amidolytic activity in the presence of the synthetic substrate for serine protease (H-D-Ile-Pro-Arg-pNA, S-2288) represented approximately 17 U/mg. In addition, more than the 60% activity of the 45 kDa fibrinolytic activity was maintained in the presence of up to 30% (w/v) sodium chloride. These findings could provide a unique fibrinolytic enzyme, leading to a potential thrombolytic agent.

• Journal of Life Science
• /
• v.30 no.10
• /
• pp.851-859
• /
• 2020

Saururus chinensis has white roots, leaves, and flowers and is known to have antibacterial activity and anti-cancer efficacy. The aim of this study was to investigate the effect of the ethyl acetate fraction of a methanol extract of Saururus chinensis (SCEA) on antioxidant activity and melanin synthesis. SCEA at 64 ㎍/ml showed 62% of the DPPH radical scavenging activity of vitamin C, and its reducing power was 33% greater than that of vitamin C. Tyrosinase activity was 26% higher and melanin synthesis was 44% higher in the presence of SCEA at 64 ㎍/ml than in a blank group in a dopa oxidation assay. MTT assay showed that SCEA displayed cytotoxicity above 0.5 ㎍/ml, and SCEA at 1 ㎍/ml increased melanin synthesis by 69% in live B16F1 cells. SCEA was also separated into 13 fractions by silica column chromatography, and fraction 2 (Fr. 2) showed the highest DPPH radical scavenging activity, reducing power, and melanin synthesis. SCEA also promoted melanin production in live cells. LC-MASS analysis showed that Fr.2 had a molecular weight of 239, and these findings suggest that SCEA could be available for the promotion of melanin synthesis in black hair.

• Korean Journal of Plant Resources
• /
• v.27 no.5
• /
• pp.401-414
• /
• 2014

In an attempt to evaluate licorice quality based on its biological activity, we grafted an on-line high-performance liquid chromatography (HPLC) bioassay method into the previously established HPLC analysis method. The common antioxidant peaks in licorices of various origin were observed through an on-line HPLC/DPPH system leading to a decrease in absorbance at 517 nm for 2,2-diphenyl-1-picrylhydrazyl (DPPH). Among them, the licorice from Youngju possessed the highest activity. Therefore, three active standard compounds from the dehydroglyasperin C, dehydroglyasperin D, and isoangustone A, were isolated and elucidated by medium pressure liquid chromatography (MPLC) and instrumental analysis such as nuclear magnetic resonance (NMR), respectively. On-line HPLC/ABTS analysis method with the simultaneous determination of three standard compounds and their radical scavenging activity was established for the quality evaluation of licorices. 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radicals (ABTS) which is stable and effective was used in replace of DPPH. The radical scavenging activity of three standards is compared with that of Trolox, known as antioxidant, showing a negative peak with a decrease in absorbance at 734 nm for ABTS. This on-line HPLC/ABTS analysis method was validated for specificity, linearity, precision and accuracy in compliance with international conference on harmonization (ICH) guideline.

• Korean Journal of Environmental Agriculture
• /
• v.29 no.3
• /
• pp.266-272
• /
• 2010

The present study was carried out to assess exposure & risk for Korean by total and inorganic As intake through agricultural products. Total arsenic analysis was performed using microwave device and ICP-MS. 50% MeOH extraction and anion-exchange HPLC-ICP-MS method has been used to determine arsenic species. 329 samples covering 20 kinds of agricultural products were collected from various retail outlets and markets across Korea. The concentration of total As was in the range of 0.001~0.718 mg/kg, while inorganic and organic arsenic species in all samples was not determined. For risk assessment, probable daily intake was calculated and compared with provisional tolerable weekly intake (PTWI, 15 ${\mu}g$/kg b.w./week for inorganic arsenic) established by JECFA. The median daily exposure to total and inorganic As by intake of agricultural products except rice was ranged 0.0002~0.012, 0.0001~0.001 ${\mu}g$/kg b.w./day, corresponding to 0.01~0.5%, 0.002~0.1% of PTWI, respectively. The median level of total and inorganic As intake through rice was 0.603 and 0.041 ${\mu}g$/kg b.w./day, and 28.1% and 1.9% of PTWI, respectively. Therefore, the level of overall exposure to arsenic for Korean through agricultural products was below the recommended JECFA levels, indicating of least possibility of risk.

• Korean Journal of Environmental Agriculture
• /
• v.37 no.1
• /
• pp.57-65
• /
• 2018

BACKGROUND: An analytical method was developed using HPLC-UVD/MS to precisely determine the residue of flusulfamide, a benzenesulfonamide fungicide used to inhibit spore germination. METHODS AND RESULTS: Flusulfamide residue was extracted with acetone from representative samples of five raw products which comprised apple, green pepper, Kimchi cabbage, hulled rice, and soybean. The extract was diluted with large volume of saline water and directly partitioned into dichloromethane to remove polar co-extractives in the aqueous phase. For the hulled rice and soybean samples, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. On an octadecylsilyl column in HPLC, flusulfamide was successfully separated from co-extractives of sample, and sensitively quantitated by ultraviolet absorption at 280 nm with no interference. Accuracy and precision of the proposed method was validated by the recovery experiment on every crop sample fortified with flusulfamide at 3 concentration levels per crop in each triplication. CONCLUSION: Mean recoveries ranged from 82.3 to 98.2% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of flusulfamide was 0.02 mg/kg as verified by the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring technique was also provided to clearly identify the suspected residue.

• The Korean Journal of Pesticide Science
• /
• v.9 no.3
• /
• pp.237-242
• /
• 2005

This experiment was carried out to develop the fast and simple method for pesticide residue analysis by using solvent free solid injector (SFSI) and to validate the efficiency of the method developed for the residue analysis of the endocrine disruptor-like pesticides such as endosulfan, metribuzin, trifluralin and vinclozolin. The samples after freeze drying were sealed in glass capillary tubes and then introduced into the heated injector of gas chromatogaphy. The required pre-heating times were 1 min for endosulfan and trifluralin, 5 min for vinclozolin, and 10 min for metribuzin. The detection limits of endosulfan in chinese cabbages, metribuzin in lettuces, trifluralin in spinachs and vinclozolin in hot peppers were 0.05, 0.1, 0.05 and 0.05 ng, respectively and their recoveries were ranged from 74%, $98{\sim}107%$, $86{\sim}95%$ and $94{\sim}95%$, respectively. The detected level of metribuzine residue in field lettuce samples by using the SFSI was 0.6 ng/mg.