• Korean Journal of Agricultural Science
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• v.45 no.4
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• pp.761-767
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• 2018

Degenerative diseases are commonly associated with excess free radicals. Acer okamotoanum, a plant endemic to Korea, is reported to have anti-oxidant, anti-cancer, and anti-viral activities. We previously isolated flavonoids from the ethyl acetate fraction of A. okamotoanum such as quercitrin (QU), isoquercitrin (IQ), and afzelin (AF). In the present study, the in vitro antioxidant activity of flavonoids such as QU, IQ, and AF isolated from the ethyl acetate fraction of A. okamotoanum were investigated by measuring the free radical scavenging activity including 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical ($^{\cdot}OH$), and superoxide anion ($O_2{^-}$). The flavonoids (QU, IQ, and AF) concentration-dependently showed a DPPH radical scavenging activity. In particular, QU and IQ showed a higher DPPH radical scavenging activity than that of AF. In addition, the flavonoids (QU, IQ, and AF) at $10{\mu}g/mL$ showed over an 80% scavenging effect against $^{\cdot}OH$ radical production. Furthermore, the $O_2{^-}$ radical scavenging activity of the flavonoids, QU, IQ, and AF increased in a dose-dependent manner. Particularly, IQ exerted the strongest scavenging activities against $^{\cdot}OH$ and $O_2{^-}$ radicals among the other flavonoids. These results indicate that the flavonoids from A. okamotoanum, in particular IQ, would have a protective activity against oxidative stress induced by free radicals, and potentially be considered as a natural antioxidant agent.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.296-313
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• 2014

A QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) multiresidue method was developed for the simultaneous analysis of 124 pesticides in soil by LC-MS. The procedure involved liquid extraction of soil immersed with 0.2N $NH_4Cl$ by acetonitrile with 1% acetic acid, followed by anhydrous $MgSO_4$ and sodium acetate, and dispersive SPE cleanup with $MgSO_4$, primary secondary amine (PSA) and $C_{18}$. The extracts were analyzed with LC-MS/MS in ESI positive mode. Standard calibration curves were made by matrix matched standards and their correlation coefficients were higher than 0.99. Recovery studies for the validation were carried out using two type soils, loam and sandy loam, at four concentration levels (0.005, 0.01, 0.02, and 0.1 mg/kg). The recoveries of pesticides were in the range of 70-120% with < 20% RSD except 4 pesticides, Benfuracarb, Ethiofencarb, Pymetrozine, and Pyrethrin. This result indicated that the method using QuEChERS and LC-MS/MS could be applied for the simultaneous determination of pesticide residues in soils.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.314-334
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• 2013

This study explored an efficient modified Quick, Easy, Cheap, Effective, Rugged and safe (QuEChERS) method combined with liquid chromatography-electrospray ionization with tandem mass spectrometric detection for the analysis of residues of 76 pesticides in brown rice, barley and corn including acidic sulfonylurea herbicides. Formic acid (1%) acid in acetonitrile and dispersive solid phase extractions used for extraction of pesticides and clean-up of the extract respectively. Two fortified spikes at 50 and 200 ng $g^{-1}$ levels were performed for recovery test. Mean recoveries of majority of pesticides at two spike levels ranged from 73.2 to 132.2, 80.9 to 136.8, 66.6 to 143.5 for brown rice, barley and corn respectively with standard error (CV) less than 10%. Good linearity of calibration curves were achieved with $R^2$ > 0.9907 within the observed concentration ranged. The modified method also provided satisfactory results for sulfonylurea herbicides. The method was applied to the determination of residues of target pesticides in real samples. A total of 26 pesticides in 36 out of 98 tasted samples were observed. The highest concentration was observed for tricyclazole at 1.17 mg $kg^{-1}$ in brown rice. This pesticide in two brown rice samples exceeded their MRLs regulated for rice in republic of Korea. Except tricyclazole none of the observed pesticides' concentration was higher than their MRLs. The results reveal that the method is effectively applicable to routine analysis of residues of target pesticides in brown rice, barley and corn.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.370-393
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• 2015

This study was conducted to compare STQ method, multi-residue method in Korean food code and QuEChERS method for validated selected and accuracy, reproducibility and efficiency. A total of 45 selected and targeted pesticides were the analyzed by GC and 5 of them were crops (apple, potato, green pepper, rice, soy bean). $R^2$ values were calculated in the standard calibration curve was over 0.990. Recovery tests were performed by three replications in two levels and the relative standard deviation of the repeated experiments was less than 30%. The average percentage of recoveries in the multi-residue method in Korean food code was 89.13%, QuEChERS method was 92.45% and STQ method was 85.28%. In addition, matrix effects in multi-residue method in Korean food code was 24.61%, QuEChERS method was 23.98% and STQ method showed 11.24%. The STQ method is easy and showed high clean-up effect in extracting the sample solution than the QuEChERS method and clean-up with C18, PLS, PSA cartridge columns. A large volume of the sample was injected in order to compensable for the problem, that occurred due to high detection limit in the analyser. When the STQ method was applied using a large volume injector, the standard calibration curve showed a higher linearity $R^2=0.990$, and method detection limit was 0.01 mg/kg. It showed an average recovery of 91.84% and the relative standard deviations of three replications repeated in two level process was less than 30% and had an average matrix effect of 17.90%.

• The Korean Journal of Pesticide Science
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• v.17 no.1
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• pp.65-71
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• 2013

The modified QuEChERS method was evaluated for rapid determination of pesticide residues in spinach by gas chromatography-nitrogen phosphorous detector (NPD) and electron capture detector (ECD). Fifty GC-amenable pesticides which were most frequently detected in monitoring were selected in the current study. Matrix-matched calibration was performed. The detector response for all pesticides was linear with determination coefficients higher than 0.995. LODs for most compounds ranged between 0.001 and 0.1 ug/g, and about 90% of the compounds had LODs of less than 0.05 ug/g. LOQs ranged from 0.001 to 0.32 ug/g, which were well below the MRLs permitted for most of pesticides. In the majority of cases, the recoveries (80-120%) and relative standard deviations (RSDs) (less than 20%) were within acceptable levels except for dichlorvos, propamocarb, chlorothalonil, dichlofluanid, cyhalothrin and fenvalerate. Also, this method which is applied to routine samples showed good results when comparing with traditional multi-residue method.

• Korean Journal of Veterinary Service
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• v.38 no.3
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• pp.173-180
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• 2015

Environmental pesticides used for insect control can be transferred from plants to animals even to livestock animals through food chain. Human beings also can be exposed to pesticides by consuming polluted dairy products, including meats, eggs and other milk products. Therefore, the Ministry of Food and Drug Safety (MFDS) established Standard for Pesticide Residue Limits in dairy products. The QuEChERS (quick, easy, cheap, effective, rugged and safe) methods for detecting residual pesticides are relatively well established for fruits and vegetables, however, the methods for meat have not been appropriately studied yet. In the present work, pyraclofos was used as an organophosphate pesticide to examine its tissue residue in experimental animals by QuEChERS methods. For this, pyraclofos (150 mg/kg body weight) was orally administered to male rats once a day for 2 days. After 6, 12, and 24 hr of the treatment, the tissue residues in liver and femoral muscle of the rats were determined using QuEChERS methods followed by HPLC analyses. In preliminary studies, the recovery rates of spiking samples of pyraclofos demonstrated approximately 109~110% from the tissues. In previous study, pyraclofos tissue residues were observed with significantly high levels in livers and muscles at 6 hr of oral treatment. Then, they were almost completely disappeared after 24 hr of the administration, indicating the orally exposed pyraclofos is rapidly absorbed and distributed to body organs, then quickly excreted from the body with a negligible level of tissue residue. The alterations in blood chemistry as well as the histopathology of heart, lung, liver, spleen and kidney have also been investigated in the experimental animals for assessing acute toxic effects of pyraclofos. The obtained blood chemistry indexes (ALT and AST) showed maximum peak values at 12 hr after the oral administration and decreased to the normal levels at 24 hr of the treatment. Histopathologic observation exhibited acute hepatic damages at 24 hr of the treatment. In conclusion, we suggest that QuEChERS method can be adequately optimized for the analysis of pyraclofos residues in animal tissues.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.278-295
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• 2014

Fast and accurate multi-residue pesticides inspecting method needs in Agro-Fishery Products Inspection Center. So, We tried to seek the optimum method using GC-TOF/MS, GC-ECD, GC-NPD after QuEChERS sample preparation. In GC-TOF/MS, 138 kinds of pesticide were spiked at 0.3 and $0.5{\mu}g/g$for the identification and quantification in lettuce sample. Recoveries of 77 pesticides were between 70 and 130% with RSD (relative standard deviation lower than 20% at $0.3{\mu}g/g$. In GC-ECD, NPD, 146 kinds of pesticide were spiked for the identification and quantification in lettuce. Recoveries of 61 species were between 70 and 130% with lower than 20%. These results indicated that GC-TOF/MS, GC-ECD, NPD analysis with the QuEChERS sample preparation can be partly applied to multi-residue pesticides in vegetables.

• Journal of Acupuncture Research
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• v.20 no.1
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• pp.61-73
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• 2003

Objective: The purpose of this study is to compare Sa-Am's Ohaeng-acupuncture(舍巖五行鍼法) with Linqi-aupuncture(六氣鍼法)-the transforms of Sa-Am's Ohaeng-acupuncture. Methods : Zheng Ge(正格), Sheng(勝格), Han Ge(寒格), Re Ge(熱格) of Sa-Am's Ohaeng-acupuncture compared with Liuqi-acupuncture(六氣鍼法)-therapy form invigoration and purgation of five zang-fu's wind. heat, dapness, dryness and cold(風熱濕燥寒). Results: 1. Liuqi-acupuncture used five-su points(五兪穴) and Zi-Ta Jing Bu Xie(自他經補瀉). 2. Liuqi-acupuncture is reinforced or reduced itself-point of itself-meridian(自經自穴) in therapy for invigoration and purgation. 3. Liuqi-acupuncture is therapy for invigoration and purgation of five zang-fu's wind, hear, dampness, dryness and cold(風熱濕燥寒). 4. Zheng Ge is similar to Bu-fa, Sheng Ge is similar to Xie-fa in Qu-xue of Ta-jing. The Qu-xue of interrestraining relations is the same, but that of interdependent relation is the difference in Qu-xure of Zi-jing. 5. Han Ge and Re Ge is similar to Re Bu Xie fa in Qu-xue fo Zi-jing but is different to in Ta-zing. For example, Han Ge is Shaofu(Bu), Yingu(Xie) but Re Ge is Shaofu(Xie), Yingu(Bu).

• The Korean Journal of Mycology
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• v.14 no.4
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• pp.247-252
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• 1986

More than 300 specimens of higher fungi were collected in Mt. Jiri National Park areas from June, 1984 to September, 1985. These higher fungi were identified. As the resulting, Clitocybe flaccida (Fr.) Kummer, Tricoloma sejuctum (Fr.) $Qu\acute{e}l.$, Melanoleuca melaleuca (Fr.) Murr., Amanita rubrovolvata Imai, Rhodophyllus lazulinus (Fr.) ,$Qu\acute{e}l.$ Paxillus involutus (Fr.) Fr., and Lactarius campholatus Fr. were new to be Korea.

• Korean Journal of Pharmacognosy
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• v.51 no.3
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• pp.207-216
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• 2020

The analysis method for qualitative analysis of the screening method that can be performed prior to the quantitative analysis of individual pesticide was reviewed in order to meet the safety standards that are being strengthened in the field of pesticide residue testing of herbal medicines. Among the residual pesticides presented in the Korean Pharmacopoeia, 56 pesticides, excluding 15 pesticides that need to be individually analyzed, were selected for analysis using QuEChERS preprocessing and GC-MS/MS, which are used in the existing agricultural products field. For each pesticide, the detection limit level of 0.001-0.005 mg/kg and the quantitative limit level of 0.002-0.017 mg/kg were confirmed. In the recovery test in which the standard was treated at a concentration of 0.02 mg/kg, it was confirmed that the proportion of pesticides satisfying the recovery of 70-120% was 85.7-96.4% for each herbal medicine, so it was confirmed that it was a level that could be reviewed by the screening method.