• 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.9 no.1
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• pp.51-59
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• 2005

Korean maximum residue limits (MRLs) for pesticides have been established based on scientific data of good agricultural practice, acceptable daily intake (ADI), food intake, average body weight and others. MRLs for pesticides are generally set under the principle that theoretical maximum daily intake (TMDI) are always below ADI. As results, 104 MRLs are going to be newly established for 24 pesticides and 102 MRLs are going to be added for 63 pesticides that have regulation already, Among new pesticides, ethaboxam and flupyrazofos are effective components that are first developed in Korea. In case of dithiocarbamates, MRLs are classified by 3 groups such as dimethyldithiocarbamates, ethylenebis (dithiocarbamate)s and propineb.

• Journal of Food Hygiene and Safety
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• v.3 no.3
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• pp.131-137
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• 1988

A pesticide monitoring survey was undertaken for the both 30 samples of pears and sweet persimmons from chief producing districts in1985 to evaluate pesticide residues in these agrcultural products and also to give basic informations in establishing maximum residue limits. Pesticide residues in pears were detected with fairly low in 7-60% of total samples. Even the maximum residue levels were only in the amount of 1/53-2/3 compared with maximum residue limits established in fruits in Environment Administration, Korea. Most of the residues (71-82%) was remained in peels of pears. Incase of sweet persimmons, captan, captafol, EPN, parathion, and phenthoate residues were also detected with fairly low in 3-20% of total samples. Presently, it is considered that pesticide residues in pears and sweet persimmons may be no harmful levels for food commodities.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.409-415
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• 2013

Post-harvest fungicide residue was measured in citrus fruits. Samples were collected from local markets in Seoul and analyzed using liquid chromatography coupled with mass spectrometry (LC-MS). LC-MS results were validated for the assay of pesticides by using linearity, accuracy, precision, and limits of detection and quantification. The linearity in the concentration ranged from 0.005 to 2.0 mg/kg ($R^2$ >0.999). Sample recoveries ranged from 80.2 to 98.3% with relative standard deviations below 4.0% for spiking levels from 0.01 to 1.0 mg/kg. The limits of detection ranged between 0.002 and 0.008 mg/kg, and the limits of quantification ranged between 0.006 and 0.027 mg/kg. The highest residue levels for carbendazim, thiabendazole, imazalil, and azoxystrobin in citrus fruits were 0.541, 0.958, 0.721, and 0.052 mg/kg, respectively. The pesticide residues found in citrus fruits were blow maximum residue limits (MRLs) and are not a serious public health problem.

• Current Research on Agriculture and Life Sciences
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• v.31 no.4
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• pp.272-279
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• 2013

The dissipation patters of the triazole fungicides flusilazole and myclobutanil in apples were investigated to establish the biological half-lives and pre-harvest residue limits (PHRLs). The residual amounts of the fungicides sprayed with single or triple doses were below the maximum residue limits (MRL) for apples established by Ministry of Food and Drug Safety. The dissipation constants of the fungicides in the apples were 0.0513 for flusilazole and 0.0244 for myclobutanil meaning their biological half-lives were calculated as 6.2-6.7 days for flusilazole and 13.3-24.8 days for myclobutanil. The PHRLs calculated using the dissipation constants indicated that the residual amounts of flusilazole and myclobutanil in the apples at the harvesting date would be below the MRLs if their residual amounts were 0.43 and 0.59 mg/kg, respectively, at 7 days prior to harvesting the apples.

• Food Science and Industry
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• v.43 no.2
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• pp.2-23
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• 2010

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.328-335
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• 2015

BACKGROUND: The present investigation was aimed to predict the pre-harvest residue limits (PHRLs) of the fluopicolide and metrafenone on cherry tomato and to estimate their half-life and characteristics of the residues.METHODS AND RESULTS: Pesticides were treated once on cherry tomato in field 1 and 2 under the standard application rate. The samples were collected 7 times at the end of 0(2 hours after pesticides spaying), 1, 2, 3, 5, 7 and 10 days before harvest. Residues of fluopicolide and metrafenone were analyzed by the LC-MS/MS. In this study, the method limit of quantification (MLOQ) for both fluopicolide and metrafenone in cherry tomato was found to be 0.005 mg kg-1. Their recovery levels were 92.7∼94.8% and 82.6∼88.0%, shown with coefficient of variation of less than 10%. Half-life of fluopicolide and metrafenone in field 1 and 2 were found to be 15.0 days and 12.8 days, 18.9 days and 21.5 days, respectively.CONCLUSION: Based on the results, this study shows the level of PHRL on cherry tomato is 0.27 mg/kg for fluopicolide and 2.29 mg/kg for metrafenone at 10 days before harvesting. The present study indicates the residues of both pesticides on cherry tomato will be below maximum residue limit (MRL) at harvest.

• Journal of Applied Biological Chemistry
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• v.65 no.3
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• pp.173-181
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• 2022

This study was carried out to investigate the residual characteristics of flubendiamide in kale to establish pre-harvest residue limits (PHRL) and the removal efficiency according to the washing solvent and method. Field tests were conducted at two different greenhouses, field 1 (Anseong-si, Gyeonggi-do) and field 2 (Incheon-si, Gyeonggi-do). According to the safe use guidelines kale was sprayed with flubendiamide twice every 10 days and harvested 0 (after 2 h), 1, 2, 3, 5, 7 and 10 days after the final application. The biological half-live of flubendiamide in kale was calculated based on dissipation curves of the pesticide in samples analyzed by liquid chromatography coupled with tandem mass spectrometry. In the analysis, method limits of quantitation (MLOQ) were 0.01 mg/kg, and recoveries performed with two different fortification levels of 10 MLOQ and maximum residue limit (0.7 mg/kg) were 104.2±3.6 and 101.9±10.2%, respectively. The dissipation rate constant of flubendiamide in kales were 0.2437 at field 1 and 0.1981 at field 2. PHRL calculation equations obtained using the dissipation constants estimated as follows: if the residual concentration of flubendiamide in kale on 10 days before harvest is less than 8.0 mg/kg, the residual concentration on the harvest would be under MRL. The removal of flubendiamide from kale was the greatest when it was washed with vinegar (39.8%), followed by baking soda (31.7%), calcium powder (30.2%), neutral detergent (27.2%), and tap water (15.9%). The results of this study would be useful for both farmers and consumers to produce or consume safe agricultural products.

• Journal of Preventive Veterinary Medicine
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• v.42 no.4
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• pp.171-176
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• 2018

A study of the tissue depletion of florfenicol (FFC) administered orally to pigs at a dose of 0.05 kg/ton feed for 7 days was performed. Sixteen healthy cross swine were administered with FFC. Four treated animals were arbitrarily selected to be sacrificed 1, 3 and 5 days after the end of treatment. FFC residue concentrations in muscle, liver, kidney, and fat were determined using high-performance liquid chromatography (HPLC) with ultraviolet photometric detector at 230 nm. The correlation coefficient ($R^2$) of the calibration curve for florfenicol amine (FFCa) was > 0.997 and the limits of detection and quantification were 0.012 and $0.040{\mu}g/mL$, respectively. Recovery rates in swine edible tissues ranged from 79.1 to 93.5%. In the FFC-treated group, FFC residues at 3 days post-treatment were below the maximum residue limits (MRLs) in muscle, kidney and fat, and those at 5 days post-administration were below the MRLs in all edible tissues. These results suggest that the withdrawal period of FFC after the drug treatment might be 5 days, which is a sufficient amount of time for reduction of the FFC residues below the MRLs in all edible tissues.

• Korean Journal of Veterinary Service
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• v.40 no.1
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• pp.79-82
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• 2017

We investigated the residues of ${\beta}-agonist$ (zilpaterol, ractopamine and clenbuterol) using LC-MS/MS in raw meat in Seoul. The recoveries ranged between 76.7~89.9% in beef respectively. The limits of detection were $0.01{\sim}0.09{\mu}g/kg$ and the limits of quantification were $0.03{\sim}0.28{\mu}g/kg$ respectively. Residues of ${\beta}-agonist$ drugs which exceeded maximum residue limits (MRL) were not exceed in any of the 267 samples.