• Korean Journal of Environmental Agriculture
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• v.39 no.3
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• pp.246-252
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• 2020

BACKGROUND: Pesticides are broadly used to control weeds and pests, and the residues remaining in crops are managed in accordance with the MRLs (maximum residue limits). Therefore, an analytical method is required to quantify the residues, and we conducted a series of analyses to select and validate the quick and simple analytical method for tolpyralate in five agricultural products using QuEChERS (quick, easy, cheap, effective, rugged and safe) method and LC-MS/MS (liquid chromatography-tandem mass spectrometry). METHODS AND RESULTS: The agricultural samples were extracted with acetonitrile followed by addition of anhydrous magnesium sulfate, sodium chloride, disodium hydrogencitrate sesquihydrate and trisodium citrate dihydrate. After shaking and centrifugation, purification was performed with d-SPE (dispersive-solid phase extraction) sorbents. To validate the optimized method, its selectivity, linearity, LOD (limit of detection), LOQ (limit of quantitation), accuracy, repeatability, and reproducibility from the inter-laboratory analyses were considered. LOQ of the analytical method was 0.01 mg/kg at five agricultural products and the linearity of matrix-matched calibration were good at seven concentration levels, from 0.0025 to 0.25 mg/L (R²≥0.9980). Mean recoveries at three spiking levels (n=5) were in the range of 85.2~112.4% with associated relative standard deviation values less than 6.2%, and the coefficient of variation between the two laboratories was also below 13%. All optimized results were validated according to the criteria ranges requested in the Codex Alimentarius Commission (CAC) and Ministry of Food and Drug Safety (MFDS) guidelines. CONCLUSION: In conclusion, we suggest that the selected and validated method could serve as a basic data for detecting tolpyralate residue in imported and domestic agricultural products.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.149-155
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• 2002

Two pesticides commonly used for lettuce cultivation including chlorpyrifos and procymidone were subjected to a field residue trial to ensure safety of terminal residues in the harvest. After pesticides were applied at standard and double rates in a foliar spray, leaf persistence of their residues was investigated far 10 days prior to harvest. Even though far exceeded the tolerances, initial leaf residues were rapidly dissipated with time and remained only 0.4$\sim$7.2% of the residues in the harvest. As well fitted by the first-order kinetics, biological half-lives of the pesticide residues in lettuce leaves ranged 1.2$\sim$2.6 days. Slow dissipation of the residues in the harvest was observed during storage at room temperature and 4$^{\circ}C$ for 7 days. Portions of dislodgeable residues which resided in detergent washings decreased as time elapsed. Patterns in dissipation and distribution of dislodgeable residues were not largely affected by the application rate of pesticides. It is concluded that timing of pesticide application, that is, pre-harvest interval would be the first factor to determine the terminal residue level in edible portions of lettuce.

• Journal of Biosystems Engineering
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• v.30 no.2 s.109
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• pp.114-120
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• 2005

In this study, a biological reaction and measurement control system was developed to rapidly measure the insecticide imidacloprid residues in agricultural products. The biological reaction part of the system was designed to include micro-pumps and valves for fluid transport, and a polystyrene covet as a reaction chamber. The measurement control part of the system consisted of a photodiode with a light-emitting diode for optical density measurement, and a control microcomputer to implement assay. Signal output was read as the rate of change in optical density at 645 nm. The sensitivity of the system was 2.2 ng/mL ($IC_50$). The system could execute a measurement cycle in about 19 minutes. Research will be continued to develop an automatic sampler fur imidacloprid residues from agricultural products.

• Journal of Food Hygiene and Safety
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• v.20 no.3
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• pp.165-174
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• 2005

This survey was conducted to monitor the current status of pesticide residues in agricultural products collected in wholesale markets and big retailers in Gwangju, in 2004. A total of 751 samples was analyzed by multiresidue method. Vegetables and fruits accounted for the largest proportion of the commodities analyzed and those two commodity groups comprised 604 $(80\%)\;and\;83\;(11\%)$ of the total number of 751 samples. Of these 751 samples, 112 samples $(14.9\%)$ had pesticide residues and 29 samples $(3.9\%)$ had violative residues. The detection rate was the highest $25\%$ in January and the lowest $9.5\%$ in June. The violation rate was the highest $7.0\%$ in March and the lowest $0\%$ in April. The violation rate in wholesale products was higher than that in big retailer products, $5.8\%$ verses $3.5\%$. And of 112 samples with pesticide residues, the agricultural product in which the pesticide residues were the most flequently detected was perilla leaf $(17.9\%)$ followed by korean lettuce $(16.1\%)$, spinach $(8.0\%)$ and korean cabbage $(5.4\%)$ and among 112 samples, 22 samples $(20\%)$ had more than one pesticide. Procymidone $(20.3\%)$, endosulfan $(18.2\%)$, dimethomorph $(13.3\%)$, chlorpyrifos $(7.7\%)$ and azoxystrobin $(6.3\%)$ were the most frequently found in agricultural product analyzed.

• Analytical Science and Technology
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• v.34 no.1
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• pp.1-8
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• 2021

An analytical method was developed and optimized for the quantification of a plant growth regulator, 2,6-diisopropylnaphthalene (2,6-DIPN), in agricultural products using gas chromatography-tandem mass spectrometry. The samples were extracted, partitioned, and were purified using a Florisil® cartridge. To validate the analytical method, its specificity, linearity, limit of detection (LOD) and limit of quantification (LOQ) of the instrument, LOQ of the analytical method (MLOQ), accuracy, and repeatability were considered. The method displayed excellent results during validation, and is suitable for the determination and quantification of the low residual levels of the analyte in the agricultural samples. All of the results with the optimized method were satisfactory and within the criteria ranges requested in the Codex Alimentarius Commission guidelines and the Ministry of Food and Drug Safety guidelines for pesticide residue analysis. The developed method is simple and accurate and can be used as a basis for safety management of 2,6-DIPN.

• The Korean Journal of Pesticide Science
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• v.14 no.2
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• pp.86-94
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• 2010

This study was conducted to monitor the current status of pesticide residues in agricultural products before auction at whole markets in Busan area from March 2006 to December 2008. Of the 7,237 samples that were analyzed by multiresidue methods, 1,164 samples (16.1%) had pesticide residues and 231 samples (3.2%) exceeded the maximum residue limits (MRLs). 181 samples of the 231 samples exceeding MRLs were applied to the tentative limits because the use of the pesticides for the agricultural products was not established against the MRLs in the Korea Food Code, and it is equivalent to 78.4%. The order of pesticides exceeding MRLs was endosulfan, procymidone, chlorothalonil, ethoprophos, chlorpyrifos, diethofencarb, kresoxim-methyl and EPN. Of 211 samples with two or more pesticides residues, the residues exceeded the MRLs in 80 samples and it is equivalent to 37.9%. This study results suggested that pesticide residues exceeding MRLs could be attributed to the use of inapplicable pesticides for agricultural products and the use of two or more pesticides.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.365-366
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• 2008

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.130-137
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• 2020

BACKGROUND: Mefentrifluconazole and triticonazole are the triazole fungicides. The maximum residue levels for agricultural products need to be set up. Therefore, development of the official analytical method for determination of mefentrifluconazole and triticonazole residues from agricultural crops was necessary due to safety management, and then a simultaneous analytical method was developed for the determination of mefentrifluconazole and triticonazole in agricultural crops. METHODS AND RESULTS: Samples were extracted using acetonitrile and purified using dispersive solid phase extraction, and then detected with liquid chromatograph-tandem mass spectrometry (LC-MS/MS). Matrix-matched calibration curves (0.0025-0.25 ㎍/mL) were linear into a sample extract with r²>0.99. For validation, the recovery test was carried out at three fortification levels (LOQ, 10 LOQ and 50 LOQ) from agricultural samples. The results for mefentrifluconazole and triticonazole ranged between 92.3 to 115.3% and 91.4 to 108.5%, respectively and RSD (relative standard deviation) values were also below 6.0%. Furthermore, inter-laboratory was conducted to validate the method. CONCLUSION: All values were corresponded with the criteria ranges requested by both the CODEX (CAC/GL 40-1993, 2003) and MFDS guidelines (2016). Therefore, the proposed method can be used as an official analytical method for determination of mefentrifluconazole and triticonazole (triazole fungicides) in the Republic of Korea.

• Analytical Science and Technology
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• v.26 no.2
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• pp.154-163
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• 2013

The maximum residue limits of pyrimisulfan is set as 0.05 mg/kg in rice in 2011, so very reliable and sensitive analytical method for pyrimisulfan residues is required for ensuring the food safety of pyrimisulfan residues in agricultural products. In this study, a rapid and sensitive analytical method was developed and validated using liquid chromatography electrospray ionization tandem mass spectrometry (LC-MS/MS) for the determination of herbicide pyrimisulfan residues in agricultural products. Average recoveries of pyrimisulfan ranged from 88.7 to 99.3% at the spiked level of 0.005 mg/kg and from 90.1 to 94.2% at the spiked level of 0.05 mg/kg, while the relative standard deviation was less than 10%. Linear range of pyrimisulfan was between 0.01~1.0 ${\mu}g/mL$ with the correlation coefficient ($r^2$) 0.999 and limit of quantification was 0.005 mg/kg. The results of method validation were satisfied Codex guideline. The results revealed that the developed and validated analytical method is possible for pyrimisulfan determination in agricultural product samples and will be used as an official analytical method.

• Journal of Haehwa Medicine
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• v.22 no.1
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• pp.129-143
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• 2013

This study was conducted to investigate the residue amount of pesticide on the 41 medicinal herbs in Daejeon area. This study was carried out to monitor the current status of pesticide residues in commercial medicinal herbs for sale of food use in 2012. It was performed using GC/ECD, GC/NPD, HPLC to analyze pesticides residues. Residues of 283 pesticides were analyzed by a simultaneous multiresidue method in 41 medicinal herbs being on sale in Daejeon. The medicinal herbs detected pesticides in 10 of 41 cases, showed a detection rate of 24.39%. The medicinal herbs which exceed the maximum residue limit were five cases as Cnidii Rhizoma, Osterici Radix, Artemisiae Capillaris Herba, Zizyphi Fructus and Alismatis Rhizoma. And pesticide residue of Cnidii Rhizoma and Alismatis Rhizoma exceeds the limit standard presented in only medicine use of KFDA. The residual pesticides which had the high detection rate were Chlopyrifos, Tebuconazole and Endosulfan in the detection of medicinal herbs. For further research, standards of Pesticide Residues in medicinal herbs should be added and more research of pesticide residues in medicinal herbs required. And standards of pesticide residues in medicinal herbs should be applied equally as medicines and food.