• Journal of Environmental Science International
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• v.15 no.1
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• pp.85-94
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• 2006

The simultaneous analysis of multi-residual pesticides was developed using a gas chromatography (GC) method. In this study, a simple and reliable methodology was improved to detect 154 kinds of pesticides in sinseng extract sample by using a liquid-liquid extraction procedure, open column chromagraphy and chromatographic analysis by CC electron capture detector (ECD) and GC nitrogen-phosphorus detector (NPD). The 154 kinds of pesticides were classified in 4 groups according to the chemical structure. The extraction of pesticides was experimented with $70\%$ acetone and dichloromethane/petroleum ether in order, and cleaned up via open column chromatography $(3\times30cm)$ packed with florisil $(30g,\;130^{\circ}C,\;12hrs)$. The final extract was concentrated in a rotator evaporator at $40^{\circ}C$ until dryness. Then the residue was redissolved to 2ml with acetone, and analyzed by GC-ECD and GC-NPD. The applied concentration of pesticides was over $1\~10{\mu}g/ml$. The recovery tests were ranged from $70.7\%$ to $115.2\%$ with standard deviations between 0.3 and $5.7\%$ of the standard spiked to the ginseng extract sample (Group $I\~IV$). The limit of detection (LOD) ranged from 0.001 to $0.099{\mu}g/ml$ (Group $I\~IV$). The 9 kinds of pesticides were not detected. The developed method was applied satisfactory to the determination of the 154 kinds of pesticides in the ginseng extract with good reproducibility and accuracy.

• The Korean Journal of Pesticide Science
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• v.15 no.4
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• pp.463-470
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• 2011

This study was carried out to survey the residual characteristic of chlorpyrifos and estimate their residues in squash before harvest. The pesticide was sprayed onto the crop at the recommended and its double rates 10 days before the prearranged harvest and sampling was done at 0, 2, 3, 5, 6, 7 and 10 days after spraying. The amounts of the chlorpyrifos residue in the crop was analyzed by chromatographic method. Limit of detection (LOD) of chlorpyrifos was 0.005 mg/kg and its recovery ranged from 95.21 to 102.69%. The initial concentration of chlorpyrifos sprayed with recommended dose exceeded its MRL of 0.1 mg/kg but its concentration was less than its MRL 10 days after application. However its concentration in case of the double dose was over its MRL both immediately and 10 days after application. Biological half-lives of chlorpyrifos sprayed onto squash was 2.5 and 2.9 days at the recommended and double doses, respectively. Ten days later, the residual concentration of chlorpyrifos in squash was decreased substantially. The concentration of chlorpyrifos was estimated in squash at the given day using its regression equations. The estimated concentration of chlorpyrifos in case of application with recommended dose was below its MRL at 10 days after application but its concentration in case of application with double dose was over its MRL at 10 days of the prearranged harvest. The rate of the estimated daily intake (EDI) of chlorpyrifos to its acceptable daily intake (ADI) was 282% right after application but it decreased to less than 18% at 10 days of the prearranged harvest.

• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.531-536
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• 2013

We developed a simple, sensitive, and specific analytical method for prometryn using gas chromatography-mass spectrometry (GC-MS). Prometryn is a selective herbicide used for the control of annual grasses and broadleaf weeds in cotton and celery crops. On the basis of high specificity, sensitivity, and reproducibility, combined with simple analytical operation, we propose that our newly developed method is suitable for use as a Ministry of Food and Drug Safety (MFDS, Korea) official method in the routine analysis of individual pesticide residues. Further, the method is applicable in clams. The separation condition for GC-MS was optimized by using a DB-5MS capillary column ($30m{\times}0.25mm$, 0.25 ${\mu}m$) with helium as the carrier gas, at a flow rate of 0.9 mL/min. We achieved high linearity over the concentration range 0.02-0.5 mg/L (correlation coefficient, $r^2$ >0.998). Our method is specific and sensitive, and has a quantitation limit of 0.04 mg/kg. The average recovery in clams ranged from 84.0% to 98.0%. The reproducibility of measurements expressed as the coefficient of variation (CV%) ranged from 3.0% to 7.1%. Our analytical procedure showed high accuracy and acceptable sensitivity regarding the analytical requirements for prometryn in fishery products. Finally, we successfully applied our method to the determination of residue levels in fishery products, and showed that none of the analyzed samples contained detectable amounts of residues.

• Journal of Food Hygiene and Safety
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• v.33 no.3
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• pp.176-184
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• 2018

The aim of the present work was to develop simultaneous methods of quantification of carazolol, azaperone, and azaperol residues in livestock and fishery products using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Samples were extracted from beef, pork, chicken, egg, milk and shrimp using acetonitrile (ACN); while flat fish and eel were extracted using 80% ACN. For purification, ACN saturated n-hexane was used to remove fat composition. The standard calibration curves showed good linearity as correlation coefficients; $r^2$ was > 0.99. Average recoveries expressed were within the range of 67.9-105% for samples fortified at three different levels ($0.5{\times}MRL$, $1{\times}MRL$ and $2{\times}MRL$). The correlation coefficient expressed as precision was within the range of 0.55-7.93%. The limit of quantification (LOQ) was 0.0002-0.002 mg/kg. The proposed analytical method showed high accuracy and acceptable sensitivity based on Codex guideline requirements (CAC/GL71-2009). This method can be used to analyze the residue of carazolol, azaperone, and azaperol in livestock and fishery products.

• The Korean Journal of Pesticide Science
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• v.20 no.4
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• pp.319-325
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• 2016

This study was conducted to investigate residual organochlorine pesticides in green house soil and oriental melon, green pepper, and lettuce. The majority of them were designated as persistent organic pollutants (POPs) by the international community at the Stockholm Convention on Persistent Organic Pollutant. Extraction and clean-up method were developed using the QuEChERS method for residual organochlorine pesticides (OCPs) in soil and oriental melon, green pepper and lettuce. Recovery of OCPs in greenhouse soil and oriental melon, green pepper, and lettuce ranged from 73.3-110.6%. Limit of detection (LOD) of OCPs in soil and 3 crops were 0.01-0.08 and $0.11-0.17{\mu}g/kg$. The residues of OCPs in oriental melon, green pepper and lettuce greenhouse soil were analyzed by the developed method, and dieldrin, ${\beta}-endosulfan$ and endosulfan sulfate were detected at 1.4-72.5, 0.1-78.7 and $0.0-214.1{\mu}g/kg$, respectively. The detection frequency of 3 compounds in soils were 52 (29.7%), 34 (19.4%) and 57 (32.6%) among 175 samples, respectively. However, these compounds were not detected in all crop samples. The residue level in 3 crops were lower than 1/58.8 of maximum residue level of them. These results showed that the OCPs residue in oriental melon, green pepper, and lettuce greenhouse soil were not as high as crop safety threatening.

• The Korean Journal of Pesticide Science
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• v.15 no.3
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• pp.269-277
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• 2011

Recent outbreak of new diseases and pests which were introduced from abroad, seriously hampered both quality and safety of paprika fruits. This study has been carried out to aid an establishment of guideline for safe use of pesticides and reduction of their residues on paprika. Systemic fungicides boscalid and pyraclostrobin of either mixed (a.i.; 13.6+6.8%) or single (a.i.; 47 and 18.8%, respectively) water dispersible granule formulation(WG) products were sprayed with recommended or double dosage on paprika grown in green house at March and June. To draw pre-harvest residue limit, residues of each fungicide were analyzed from fruits collected eight times from 18 to 1 day pre-harvest. The biological half-lives of both boscalid and pyraclostrobin in mixed formulation in March and June were slightly shorter than those of single formulation which ranged from 14.4 to 20.1 days. Residue levels of both fungicides of single formulation in fruits in June were about one lower compared to those in March. However, application of double dosage frequently exceeded MRLs from fruits grown both seasons. These results showed that residue levels on fruits persisted longer period of time, more than two weeks, and so the case applied in winter season. The dissipation of fungicides on leaves and fruits was compared. The distribution of both fungicides in leaves was 20-200 times higher than that of fruits and persisted up to 18 days of pre-harvest period at the concentration of 10-40 ${\mu}g\;g^{-1}$. This study indicated that the mixed formulation product exhibited low residues in fruits, but high and long enough to pathogen growth in leaves.

• The Korean Journal of Pesticide Science
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• v.16 no.1
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• pp.35-42
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• 2012

This study was carried out to elucidate the residual characteristics and calculate processing factors of difenoconazole in ginseng and its processed products, such as dried ginseng, red ginseng and their water and alcohol extracts. The pesticide was sprayed onto the ginseng according to its pre-harvest intervals in 2009 (four-year-old ginseng) and 2010 (five-year-old ginseng). Harvested ginseng was processed to dried ginseng, red ginseng and their extracts according to the commercially well-qualified conventional methods provided by the Korea Ginseng Corporation. Limit of detection (LOD) and limit of quantitation (LOQ) of difenoconazole in fresh ginseng were 0.001 and 0.003 mg/kg, respectively. In case of processed ginseng products, their levels were 0.002 and 0.007 mg/kg, respectively. Concentration of difenoconazole in both fresh ginseng and its processed products increased with the experimental period. Processing factors, calculated as a ratio of difenoconazole concentration in processed products to fresh ginseng were found to be 1.71 to 2.17 and 1.62 to 2.03 in case of dried and red ginseng, respectively, while those for their extracts ranged from 1.76 to 2.98. In case of five-year-old dried ginseng and red ginseng as well as their extracts, the ranges of processing factor of difenoconazole were found to be 2.9 to 3.1, 1.9 to 2.2 and 2.4 to 4.7, respectively.

• Journal of Food Hygiene and Safety
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• v.35 no.4
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• pp.365-374
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• 2020

This study was conducted to monitor the residual pesticides on a total of 320 stalk and stem vegetables from January 2019 to December 2019 in the Incheon metropolitan area. Pesticide residues in samples were analyzed by the multi-residue method for 373 pesticides using GC-MS/MS, LC-MS/MS, GC-ECD, GC-NPD and HPLC-UVD. Risk assessment was also carried out based on the amount of stalk and stem vegetables consumed. The linearity correlation coefficient for the calibration curve was 0.9951 to 1.0000, LOD 0.002 to 0.022 mg/kg, LOQ 0.005 to 0.066 mg/kg and recovery was 82.0 to 108.0%. According to the monitoring of pesticides, 36 (11.3%) of 320 were detected with pesticide residues and 3 (0.9%) samples exceeded the maximum residual limit. The detection frequency for Chinese chives and Welsh onion was higher than that for other stalk and stem vegetables. The frequently detected pesticides were etofenprox, procymidone, fludioxonil, and pendimethalin. As a tool of risk assessment through the consumption of pesticide detectable agricultural products, the ratio of estimated daily intake (EDI) to acceptable daily intake (ADI) was calculated in the range of 0.0062-24.1423%. These results indicate that there is no particular health risk through consumption of commercial stalk and stem vegetables detected with pesticide residues.

• Journal of Food Hygiene and Safety
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• v.34 no.4
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• pp.348-353
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• 2019

This study was conducted to monitor the carbendazim residues in soybean and mungbean sprouts using LC-MS/MS method. Eighty-two samples were collected from markets in western Seoul. No carbendazim was detected in mungbean sprouts, however, it was detected in 6 among 59 soybean sprout samples showing a 10.2% of detection rate. Among these 6 carbendazim- detected soybean sprout samples, five exceeded the maximum residue limit presenting 83.3% of violation rate. The mean concentration in the detected samples was 0.063 mk/kg (0.012 ~ 0.104 mg/kg) and 5 of the 6 detected samples came from bulk sold products. None of the samples came from domestic products; three were from imported products and 3 were from unidentified sources. Risk assessment for the carbendazim from soybean sprout dietary intake was deemed safe and at less than 1 %Acceptable Daily Intake.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.19-25
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• 2000

The leaching behaviour of quinclorac was elucidated using soil columns. On top of each glass column packed with a rice paddy soil up to the 30 cm height were applied three different treatments of [$^{14}C$]quinclorac: quincloiac only (T-1), quinclorac adsorbed onto active carbon (T-2), and quinclorac adsorbed onto a mixture of active carbon and $Ca(OH)_{2}$ (T-3). Half of the columns were planted with rice plants for 17 weeks and half of them unplanted for comparison. Average amounts of $^{14}C$-activity percolated from tile soil columns without rice plants in T-1, T-2, and T-3 were 81.1%, 27.8% and 48.0%, respectively, of tile originally applied $^{14}C$, whereas those with rice plants grown were 36.8%, 9.6% and 11.0%, respectively, indicating that the leaching of [$^{14}C$]quinclorac was significantly affected by vegetation and by treatment with the adsorbents. The bioavailability of the herbicide to rice plants in T-1, T-2, and T-3 were 13.6%, 11.0% and 13.9%, respectively. The residue levels of quinclorac in the edible part of rice grains would be far less than the maximum residue limit (MRL, 0.5 ppm). After the leaching, the amounts of $^{14}C$ remaining in soil in with rice planting T-1, T-2, and T-3 were 36.3%, 73.7%, and 61.8%, whereas those without rice planting were 19.7%, 71.1%, and 52.3%, respectively. The balance sheets indicate that [$^{14}C$]quinclorac translocated to rice shoots would be lost by volatilization and/or in other ways in T-1 and T-3. The $^{14}C$-activity partitioned into the aqueous phase of the leachates collected from all treatments was less than 7% of the total, but it increased gradually with time in the case of rice growing, suggesting tile formation of some polar degradation products.