• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.308-314
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• 2012

In order to monitor the residual pesticides in environment friendly agricultural commodities, fruits and fruiting vegetables. Twenty-five agricultural commodities were collected twice in May and August 2011 from nine environment friendly agricultural commodities-selling supermarkets and retail stores located in eight major cities in Korea. The number of each agricultural commodity collected, 555 samples in total, was 152 organic agricultural products, 202 pesticide-free agricultural products and 201 low-pesticide agricultural products. Pesticide residues in samples were analyzed by multiresidue method for 245 pesticides using a GC-ECD/NPD and an HPLC-DAD/FLD and the peaks suspected as pesticides were identified with a GC/MSD. As a result of pesticide residue analysis, three pesticides, bifenthrin, EPN and chlorpyrifos, were detected from four samples including apple, representing a detection rate of 0.72%. The residue levels of the four pesticide-detected samples were less than their maximum residue limits (MRLs) but one pesticide EPN detected from pear exceeded its legible criterion of one twentieth MRL. Estimated daily intakes of the pesticides detected from fruits and fruiting vegetables were less than 0.76% of their maximum permissible intake.

• Korean Journal of Veterinary Service
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• v.38 no.4
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• pp.259-264
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• 2015

We investigated the residues of 6 cephalosporins (cefquinome, cephalexin, cephalonium, cefazolin, ceftiofur, cefuroxime) using LC-MS/MS in raw meat in Seoul. This method involves extraction of the residue from the meat by distilled water and methanol followed by a manual of residue analysis published by the National Institute of Food and Drug Safety Evaluation. The recoveries ranged between 74.71~90.01% in beef, 73.37~101.40% in pork and 70.87~95.53% in chicken, respectively. The limits of detection were 0.0004~0.0563 mg/kg, and the limits of quantification were 0.001~0.169 mg/kg respectively. Residues of cephalosporins which exceeded maximum residue limits (MRL) were not exceed in any of the 287 samples. However, it is necessary to develop multi-method, which includes the active metabolites of ceftiofur.

• Korean Journal of Veterinary Service
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• v.45 no.3
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• pp.229-236
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• 2022

This study describes an analytical method based on LC-MS/MS for the quantitation of 5 fluoroquinolones (Enrofloxacin, Ciprofloxacin, Marbofloxacin, Norfloxacin and Danofloxacin) in meat, and was applied to 230 meat samples for validation. Quantitation was performed based on a matrix-matched calibration to compensate for the matrix effect on the electrospray ionization. Good linear calibrations (R²≥0.998) were obtained for all fluoroquinolones at 6 concentrations of 1~50 ㎍/kg. Satisfied recoveries of all fluoroquinolones were demonstrated in spiked meat at three levels from 10 to 50 ㎍/kg. The recoveries ranged between 75.8~99.2% in beef, 80.1~99.6% in pork and 72.2~99.8% in chicken, respectively. The limits of quantitation (LOQs) for fluoroquinolones ranged from 0.7 to 3.2 ㎍/kg. We also monitored fluoroquinolones residue in the sample (beef 107, pork 71, chicken 52) using LC-MS/MS. Residues of fluoroquinolones which exceeded maximum residue limits (MRL) were not exceed in any of the 230 samples.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.195-203
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• 2015

Quintozene, pentachloronitrobenzene (PCNB) is a contact fungicide for control of soilborne phytopathogenic fungi during cultivation of diverse crops. It was introduced to agricultural use around 1930's as a substitute for mercurial disinfectants. Although quintozene had been first registered in Korea on 1969. However, now it was banned to use due to its high residue levels in selected harvest products. Also, high possibility is expected that the residue may be contained in imported agricultural commodities as it is still used widely over the world. Therefore, this study was conducted to establish a determination method for quintozene residue in crops using GC/ECD/MS. Quintozene residue was extracted with acetonitrile from representative samples of five raw products which comprised hulled rice, soybean, Kimchi cabbage, green pepper, and apple. The extract was diluted with saline water, and n-hexane partition was followed to recover quintozene from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The quintozene was quantitated by GLC with ECD, using a DB-1 capillary column. The crops were fortified with quintozene at 3 levels per crop. Mean recoveries ranged from 79.9% to 102.7% in five representative agricultural commodities. The coefficients of variation were less than 4.3%. Quantitative limit of quintozene was 0.004 mg/kg in representative five crop samples. A GC/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 quintozene in agricultural commodities.

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

• Korean Journal of Medicinal Crop Science
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• v.24 no.3
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• pp.237-245
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• 2016

Background: Cyanazine is used as a pre-emergent herbicide once during the growing season to control weeds of many upland crops worldwide. This study aimed to establish a method to determined cyanazine residue levels in major medicinal crops by using high performance liquid chromatography-UV detection/mass spectometry (HPLC-UVD/MS). Methods and Results: Cyanazine residue was extracted with acetone from the raw products of four representative medicinal plants - Scutellaria baicalensis, Paeonia lactiflora, Platycodon grandiflorum and Angelica gigas. The extract was diluted with a large volume of saline water and directly partitioned into dichloromethane to remove polar co-extractives in the aqueous phase. It was then purifined using optimized Florisil column chromatography. HPLC analysis conducted using an octadecylsilyl column allowed the successful separation of cyanazine from co-extractives of the samples, and the amount was sensitively quantified by ultraviolet absorption at 225 nm with no interference. The accuracy and precision of the proposed method were validated by conducting recovery experiments on each medicinal crop sample fortified with cyanazine at two concentration levels per crop in triplicate. Conclusions: The mean recoveries ranged from 91.2% to 105.3% for the four representative medicinal crops. The coefficients of variation were less than 10%, irrespective of the sample types and fortification levels. The limit of quantification of cyanazine was 0.02 mg/kg as verified by the recovery experiment. A confirmatory method was performed by liquid chromatography/MS using selected-ion monitoring technique to clearly identify the suspected residue.

• The Korean Journal of Pesticide Science
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• v.20 no.1
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• pp.23-29
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• 2016

This study was carried out to survey residual characteristics of pesticide in fresh ginsengs collected from 45 markets at 15 regions in Korea using multiresidue analysis with a GC-MS/MS and an LC-MS/MS. After residue analysis was performed, the pesticides detected from ginsengs were quantitated using their analytical methods validated by recovery tests with a GC-ECD/NPD. As a results of analysis of pesticide residue, cypermethrin, fenitrothion, fludioxonil, thifluzamide, and tolclofos-methyl were detected from 16 samples among 45 samples in total, indicating detection rate was 35.6%. Tolclofos-methyl was found to be highest in detection frequency in ginseng. Fenitrothion that has not established maximum residue limit and pre-harvest interval for ginseng was detected. The amounts of all pesticides detected were less than their MRLs. Ratios of estimated daily intakes to acceptable daily intakes of the detected pesticides in ginseng were found to be from 0.03 to 16.67%.

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.544-552
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• 1998

A random study of 574 dairy farms in Gyeongnam area was designed to determine 1) management factors that may be associated with the occurrence of drug residues; 2) the dairy farmer's attitudes and knowledge about residues; 3) how these variables influence the occurrence of residues in dairy cattle. Management factors perceived as having the greatest influence on drug residues in milk were insufficient knowledge about withdrawal periods, errors due to hired help, insufficient identification and record of animals treated for mastitis, dry cow treatment for mastitis, and metritis treatment. Seventy-one percent of farms with residues problem used mixed own feeds compared with twenty-nine percent of farms with premedicated feeds. Factors significantly associated with the occurrence of residues were herd size, increased number of hired persons, increased frequency of use of mixed-own feeds, category of medicated feed, and producer's attitude toward the public health significance of residues. Our findings suggest that residue occurrence was mainly associated with errors due to hired help, insufficient knowledge about withdrawal periods, poor animal identification and records of treatment animals and use of medicated feeds. Any residue avodiance educational program needs to stress how to deal with these factors. This educational program should be directed to dairy farmers and employees, especially temporary employees. In addition, Dairy farmer's attitudes and knowledge about drug residues need to be improved. More evidence on the public healths significance of residues should be available to them. Because belife in importance of public healths concerns was related to successful residue avidance and because 81.3% of the dairy farmers with residue problem thought public healths concerns were less important than economic ones, it would be helpful to provide educational programs specifically directed to this issue. it may be useful to provide programs not only for the dairy farmers but also change of their concerns about on the public healths.

• Korean Journal of Environmental Agriculture
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• v.37 no.4
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• pp.277-282
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• 2018

BACKGROUND: At these days, the human health and environmental concerns of pesticide used for turf grass management at golf courses in Korea have increased. The objectives of the study were to determine the pesticide residues for golf course and neighboring area and evaluate the impact moved into neighboring area of pesticides treated at golf courses. METHODS AND RESULTS: Three golf courses and neighboring areas in Korea were monitored from July to October, 2017. The soil sample collection was divided the golf course into its logical parts (such as a greens, fairways, and rough) and neighboring area soil samples were collected at three different points. The water samples of the golf course and neighboring area were collected at three different points, respectively. The pesticide residues for soil and water sample were monitored by the multi-residue screening method of 98 pesticide with HPLC-MS-MS. The concentrations of detected pesticide in soil and water samples of the golf course were in the range of 0.01~1.26 mg/kg and 0.0001~0.0089 mg/kg, respectively. The residue levels for detected pesticides in neighboring area were at 0.01~0.04 mg/kg and 0.0001~0.0029 mg/kg, respectively, well below those level in golf course. CONCLUSION: This study indicate that the pesticide residue levels of golf course and neighboring area in Korea may not a possible risk of exposure on soil and aquatic environment. For future work, more monitoring should be performed so that the evaluation data becomes more valid.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.6
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• pp.902-908
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• 2010

In 2008, we monitored residual pesticides of 15 agricultural products such as rice, corn, pea, chestnut, mandarin, lemon, onion, pineapple, lettuce, chard, sweet potato stalk, burdock, squash, sweet pepper and mushroom. Agricultural commodities were collected from markets in 22 provinces (Seoul, Busan, Incheon, Daegu, Ulsan, Daejeon, Gwangju, Wonju, Pohang, Gumi, Changwon, Gimhae, Suwon, Seongnam, Bucheon, Goyang, Yongin, Cheongju, Cheonan, Jeonju, Yeosu, and Jeju). Total 48 pesticides were analysed by multi-residue method using GC/MS/MS. We analysed 1,064 samples and 34 samples (3.20%) were detected. Sweet potatostalk, burdock, chestnuts, peas, corn, chard, squash, mushroom and onions were found to be free from pesticide residues. 6 other agricultural products did not exceed MRLs (Maximum Residue Limits) by the Korean Food Code. Chloropyrifos and fenobucarb were particularly prevalent and also they were detected over 10 times in this monitoring. Nonetheless, the exposed quantity of the 7 residual pesticides is to be considered relatively safe, compared with the acceptable daily intake (ADI) of residual pesticides.