• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.241-248
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• 2009

Pre-Harvest Residue Limit (PHRL) of bifenthrin during cultivation of grape was established by utilizing the dissipation curve and biological half-life of bifenthrin calculated from the analysis of 0, 1, 2, 3, 5, 7, 10, 15 days after treatment of bifenthrin. Grape sample was extracted and partitioned with acetonitrile and dichloromethane, respectively, and bifenthrin was determined with GC/ECD. Limit of quantitation (LOQ) of bifenthrin was 0.01 ng. Recoveries at two fortification levels of 0.1 and $0.5\;mg\;kg^{-1}$ were $104.08\;{\pm}\;1.24$ and $92.25\;{\pm}\;3.13%$, respectively. The biological half-lives of bifenthrin were about 21 days at standard application rate, while, 23 days at double application rate. Dissipation of bifenthrin on grape was not influenced by growth dilution effect. The PHRLs of bifenthrin were recommended as 0.60 and $0.55\;mg\;kg^{-1}$ for 10 and 5 days before harvest, respectively.

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.184-192
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• 2017

BACKGROUND: This study was performed to evaluate the residue dissipation of boscalid and spinetoram on crown daisy and sweet pepper affected by the morphology of the crop. The half-lives and dissipation rate constants for boscalid and spinetoram on crown daisy and sweet pepper were calculated. And then lower limit of 95% confidence interval for dissipation rate constant could be used to propose the pre-harvest residue limit. METHODS AND RESULTS: The pesticide products diluted according to the pesticide label were applied one time on crown daisy and sweet pepper at 2 field sites, respectively. Initial concentration of boscalid and spinetoram on crown daisy after application were in the range of 72.80~117.15 mg/kg and 2.82~4.67 mg/kg, respectively. And Initial concentration of boscalid and spinetoram on sweet pepper were in the range of 1.58~1.62 mg/kg and 0.10~0.21 mg/kg, respectively. Boscalid and spinetoram for crown daisy dissipted below the maximum residue limit(MRL) at 10 and 2 days after application, respectively. All residues concentration of boscalid and spinetoram for sweet pepper below the MRL at 0 day after application. The half-lives based on dissipation rate constant for boscalid and spinetoram on crown daisy were 4.2~4.9 days and 3.0~2.4 days respectively. And the half-lives for boscalid and spinetoram on sweet pepper were 6.7~7.0 days and 2.8~4.0 days respectively. CONCLUSION: The difference in initial concentration of boscalid and spinetoram among crop commodities were due to different crop morphology with larger surface areas. This study was suggested that pre-harvest residue limit would be calculated from lower limit of 95% confidence interval for dissipation rate constant and would be useful to protect consumers by controlling the pesticide residues in crop.

• Korean Journal of Environmental Agriculture
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• v.41 no.3
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• pp.153-157
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• 2022

BACKGROUND: The residue dissipation pattern of pesticides for agricultural products during the pre-harvest period after the final application is important to prevent the maximum residue limit (MRL) violations in domestic and export markets. The MRL violations of carbendazim are observed more often in chamnamul by pesticide residue management surveys by the Ministry of Food and Drug Safety. The residue level at the pre-harvest interval (PHI) and the residue dissipation constant from the critical good agricultural practice (cGAP) trials could be estimated to meet the MRL and pose a health risk to consumers. METHODS AND RESULTS: Chamnamuls were harvested at 0, 1, 3, 5, 7, 10, and 14 days after application of carbendazim in accordance with critical GAP. The residue analysis in chamnanul was performed by HPLC-DAD with the C₁₈ column. The limit of quantitation of carbendazim was 0.04 mg/kg, and the recoveries were 74.4 - 95.8% at the two spiked levels (LOQ and 10LOQ) of carbendazim. The dissipation rates in chamnamul were calculated from the residues at the sampling days by statistical method at a 95% confidence level. The biological half-lives of residual carbendazim in the field trials 1 and 2 were 4.9 and 4.4 days, respectively. CONCLUSION(S): In this dissipation study, the residue concentrations at the recommended PHI were higher than the established MRL in Korea. Therefore, the MRL is proposed based on the residue data sets from the trials conducted at the same cGAP and the dietary exposure assessment.

• The Korean Journal of Pesticide Science
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• v.17 no.2
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• pp.77-83
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• 2013

This study was performed to investigate pre-harvest residue limit (PHRL) in amaranth, to estimate biological half-life of emamectin benzoate and identify the characteristics of the residue. Pesticides of standard and double appplication rate, were sprayed once on amaranth at 0, 1, 2, 3, 5, 7, 10, 14 days before harvest. Amaranth sample was extracted with acetonitrile and partitioned with dichloromethane, and pesticide residues were determined with LC/MS/MS. The limit of detection of emamectin benzoate was 0.01 mg/kg. Recoveries of emamectin benzoate ($B_{1a}$, $B_{1b}$) at two fortification levels of 0.1 and 0.5 mg/kg, $B_{1a}$ were $93.3{\pm}0.7%$ and $93.2{\pm}7.7%$, $B_{1b}$ were $106.6{\pm}1.9%$ and $80.5{\pm}6.6%$, respectively. The biological half-lives of emamectin benzoate were about 2.0 days at standard application rate and 1.7 days at double application rate, respectively. The PHRL of emamectin benzoate were recommended as 0.84 mg/kg for 10 days before harvest.

• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.81-87
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• 2015

The present study was aimed to predict the pre-harvest residue limits (PHRLs) of pyrimethanil (fungicide) and methoxyfenozide (insecticide) in grape, and to estimate their biological half-lives and residual characteristics. The pesticides were sprayed once on grape in two different fields 10 days before harvest. At the end of 0, 1, 2, 3, 5, 7 and 10 days after application, samples were harvested for further analysis. The residual pesticides were extracted with acetonitrile and partitioned with dichloromethane, and the high-performance liquid chromatography with diode array detector (HPLC/DAD) was employed for the residue analysis. The results obtained in the present study show that the limit of detection of both pesticides were found to be $0.01mg\;kg^{-1}$. The recoveries of these pesticides were ranged between 80.6% and 102.5% with coefficient of variation lower than 10%. The biological half-lives of both pesticides were observed in field 1 and field 2 which shows 7.7 and 7.4 days for pyrimethanil and 5.1 and 6.1 days for methoxyfenozide, respectively. Further, the PHRL of pyrimethanil and methoxyfenozide was found to be $8.90mg\;kg^{-1}$ and $5.51mg\;kg^{-1}$, respectively at 10 days before harvest. Consequently, the present study suggests that the residual amounts of both pesticides will be lower than the maximum residue limits (MRLs) when grape is harvested.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.288-293
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• 2012

The dissipation patterns of amisulbrom in cucumber under a greenhouse condition was investigated to establish biological half-life and pre-harvest residue limit (PHRL). Amisulbrom residue in/on cucumber on the day of application under standard application condition was $0.15mg\;kg^{-1}$ and decreased to $0.06mg\;kg^{-1}$ after 5 days after treatment, so that biological half-life calculated 3.6 day, while initial concentration of amisulbrom twice application 3 days interval under standard application condition was $0.35mg\;kg^{-1}$ and decreased to $0.09mg\;kg^{-1}$ after same period and the biological half-life calculated 2.4 day. PHRL was suggested by prediction curve calculated from the decay constant of amisulbrom at standard rate. For example, $1.83mg\;kg^{-1}$ at 5 days before harvest and $1.03mg\;kg^{-1}$ at 2 days before harvest were suggested.

• 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.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.97-103
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• 2018

BACKGROUND: Dissipation of acetamiprid and thiamethoxam in greenhouse grown chard samples was evaluated at 5 intervals including the pre-harvest interval after application. This study was conducted to determine the residue levels, the biological half-lives and dissipation rate of acetamiprid and thiamethoxam in chard under controlled conditions. METHODS AND RESULTS: Acetamiprid and thiamethoxam were applied in accordance with good agricultural practices for chard. Chard samples were collected at 0, 1, 2, 3, 5, 7, 10 and 14 days after application. Quantitaion was performed by HPLC-DAD system with C18 column. Limit of quantification (LOQ) of acetamiprid and thiamethoxam were both 0.02 mg/kg for chard. The recovery of acetamiprid and thiamethoxam were 77.8~107.5% and 94.3~108.6% at two concentration levels. The half-lives of pesticide dissipation in chard for two fields were 11.9 and 8.2 days for acetamiprid and 3.6 and 3.3 days for thiamethoxam respectively. The dissipation rate of acetamiprid and thiamethoxam were estimated according to the statistics method with a 95% confidence. CONCLUSION: Dissipation of acetamiprid and thiamethoxam in chard were determined under greenhouse. The concentration of acetamiprid and thiamethoxam in chards at 0 days after application were below specified by Korean MRL. Dissipation rate constant will be useful to set the pre-harvest residue limit for public health and consumer protection.

• Korean Journal of Environmental Agriculture
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• v.41 no.2
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• pp.125-134
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• 2022

BACKGROUND: It is a very important task to block distribution of the agricultural products contaminated with pesticides in advance to protect consumers from residual pesticides among the agricultural products. Therefore, this study was performed to determine residual characteristics of pesticides in time-dependent manner and present scientific evidences for pre-harvest residue limit (PHRL) setting. METHODS AND RESULTS: The tested pesticides, chromafenozide and pyridalyl were sprayed onto the kale twice (seven day intervals) and then the plant samples were collected at 0 (after 3 hours), 1, 2, 3, 5, 7, and 10 days after the last spraying. Residual concentration of chromafenozide in kale decreased with 74.9% (of decreased fraction, field 1) and 85.3% (field 2) and pyridalyl decreased with 81.2% (field 1) and 85.8% (field 2), calculated by comparisons of the concentrations at 0 day and 10 days. Also biological half-lives of chromafenozide in kale were 5.6 day (field 1) and 3.4 day (field 2), and those of pyridalyl were 4.3 day (field 1) and 3.5 day (field 2). CONCLUSION(S): If the residues of chromafenozide and pyridalyl in kale from 10 days before harvest are less than 37.6 mg/kg and 58.9 mg/kg, respectively, it is expected that safe kale below MRL can be supplied on the pre-harvest day.

• The Korean Journal of Pesticide Science
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• v.21 no.1
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• pp.62-67
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• 2017

In this study, the residue patterns of flubendiamide and pyriofenone registered in the strawberry were investigated to predict pre-harvest residue limit (PHRL). The samples were harvested at 0, 1, 2, 3, 5, 7, 10 days after treatment and the pesticide residues were analyzed by HPLC/UVD. The limit of quantification (LOQ) was $0.01mg\;kg^{-1}$ for flubendiamide and pyriofenone. The recovery levels of flubendiamide and pyriofenone were $90.9{\pm}2.2%$ and $81.9{\pm}0.8%$, $87.7{\pm}2.1%$ and $85.3{\pm}1.1%$ for spiked levels of 0.01 and $0.1mg\;kg^{-1}$, respectively. The values of biological half-lives for field 1 and field 2 were 8.1 and 7.2 days for flubendiamide, 7.0 and 6.9 days for pyriofenone. According to these results, we recommends the level of PHRL on strawberry for flubendiamide and pyriofenone as 1.87 and $3.76mg\;kg^{-1}$ at 10 days before harvest, respectively.