• Applied Biological Chemistry
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• v.23 no.1
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• pp.58-63
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• 1980

Present investigation is undertaken to evaluate residues of organochlorine pesticides and PCBs in river sediments and cultivated soils by GLC. Main sampling areas chosen were three industrial estates, Suwon, Iri and Kumi. Samples consist of river sediments and cultivated soils, in Suwon, Iri and Chilgok, which are likely to be accumulated with PCBs from nearby factories. Organochlorine pesticide residues were found in all sediments and soil samples while no PCBs residue was detected in all samples analyzed. The pesticide residues were greatest in the Suwon and least in Chilgok soils. p,p'-DDT and BHC isomers $({\alpha}-,\;and\;{\gamma}-)$ were found in all soil samples. p,p'-DDT, at the range of 0.006-0.840 ppm, was the most abundant residues among organochlorine insecticides.

• Journal of Applied Biological Chemistry
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• v.63 no.2
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• pp.153-159
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• 2020

The analytical method was established for simultaneous determination of fungicide prochloraz and its metabolites in several animal commodities using gas chromatography (GC) coupled with electron capture detector (ECD). Samples including beef meat, pork meat, chicken meat, milk, and egg were hydrolyzed with pyridine hydrochloride which converts prochloraz and its metabolites to 2,4,6-trichlorophenol (2,4,6-TCP) because residue definition for prochloraz was 'sum of prochloraz and its metabolites containing the 2,4,6-trichlorophenol moiety, expressed as prochloraz', for compliance with MRLs from animal commodities. Therefore, residual prochloraz was extracted with acetone, decomposed to 2,4,6-TCP, partitioned with dichloromethane, purified with aminopropyl SPE and quantified as 2,4,6-TCP with GC-ECD. The instrumental limit of quantitation and method LOQ (MLOQ) was 0.01 ㎍/mL and 0.02 mg/kg for prochloraz and 0.005 ㎍/mL and 0.01 mg/kg for 2,4,6-TCP, respectively. The linearity of the calibration curve was good with R² >0.995 in the range of 0.005-0.2 ㎍/mL. Fortification levels of prochloraz were 0.02 mg/kg (MLOQ) and 0.2 mg/kg (10MLOQ) for recovery tests. Overall recoveries of prochloraz were >90% with <10% of coefficient variation (C.V.). This established analytical method was fully validated and could be useful for quantification of prochloraz and its metabolites in animal commodities as official analytical method.

• Journal of Food Hygiene and Safety
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• v.6 no.2
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• pp.83-87
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• 1991

Beef, pork and chicken on the market were analyzed for determination of tetracyclines residue and decomposition of tetracyclines by heating were studied. The content of oxytetracycline was trace in chicken A, 0.09 mg/kg in C and trace in beef C, pork A and B, but in the other samples was not detected oxytetracycline. Chlortetracycline residue was 0.14, 0.02 and 0.01 mg/kg in chicken A, C and beef B respectively. In HPLC analysis, two peaks of 8.1 and 9.0 min of retention time were found from beef and pork and expected to be component of meat, and because of same retention time, the one of 9.0 min interrupted determination of tetracycline. But those were not found in chicken, therefore the residue was 0.01 mg/kg in sample A. The residue were degradated rapidly by heating of roast, but slightly by that of boiling.

• The Korean Journal of Pesticide Science
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• v.17 no.2
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• pp.107-116
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• 2013

Polar pesticides like pymetrozine (log $P_{ow}$: -0.18) are known to be difficult to analyze. The analytical method of pymetrozine using hydromatrix included in the official method of KFDA was uncommon and provided ambiguous evidence to confirm both the identity and the quantity. Therefore, precise single residue analytical method was developed in representative crops for using liquid-liquid extraction (LLE). The pymetrozine residue was extracted with methanol from 11 representative crops which comprised apple, blueberry, broccoli, cabbage, cherry, crown daisy, hulled rice, Korean cabbage, potato, rice and watermelon. The extract was purified serially by liquid-liquid extraction (LLE) and silica solid phase extraction (SPE). For rice and hulled rice samples, n-hexane partition was additionally adopted to remove nonpolar interferences, mainly lipids. The residue levels were analyzed by HPLC with DAD, using $C_8$ column. LOQ (limit of quantitation) of pymetroizinie was 1 ng (S/N > 10) and MQL (method quantitation limit) was 0.01 mg/kg. Mean recoveries from 11 crop samples fortified at three levels (MQL, 10 ${\times}$ MQL and 50 ${\times}$ MQL) in triplicate were in the range of 83.1~98.5% with coefficients of variation (CV) of less than 10%, regardless of sample type, which satisfies the criteria of KFDA. The method established in this study could be applied to most of crops as an official and general method for analysis of pymetrozine residue.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.235-240
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• 2010

In order to elucidate residual characteristics of pesticides in garlic by drying, azoxystrobin and flutolanil used for garlic were treated to the garlic by dipping for 1 and 5 min into their standard diluents and then the garlic was dried with a freeze-drier. The test pesticides were analyzed with a GLC-ECD/NPD. Recoveries of the pesticides ranged from 81.96 to 98.18%. Amount of azoxystrobin and flutolanil in fresh garlic were 0.34 and 1.18 mg/kg in case of dipping for 1 min. and 0.44 and 2.15 mg/kg in case of dipping for 5 min., respectively. Also, amount of azoxystrobin and flutolanil in dried garlic were 0.80 and 4.51 mg/kg in case of dipping for 1 min. and 1.03, 5.28 mg/kg in case of dipping for 5 minute, respectively, representing that concentration of the test pesticides in garlic were increased by drying. In case of dipping for 1 and 5 min., processing factors of azoxystrobin were 2.35 and 3.34 and those of flutolanil were 1.19 and 1.17, respectively. Reduction factors of the pesticides in garlic were range from 0.94 to 0.97, indicating that few amounts of the test pesticides in garlic were dissipated by freeze-drying.

• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.83-88
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• 1982

Residues of some organochlorine pesticides $({\alpha}-BHC,\; {\gamma}-BHC,$ heptachlor, aldrin, heptachlor epoxide, dieldrin, p,p'-DDD, p,p'-DDT) in the cultivating soils (53 samples) were evaluated in the suburbs of Gwangju-City, Jeollanam-Do. Results obtained are summarized as follows. 1) Seven organochlorine pesticides were detected in more than 60% of the sample soils except dieldrin. In particular, ${\alpha}-BHC$ was detected in almost all soil samples and residue level of p,p'-DDT was higher than that of the others. 2) Detection frequencies and residue levels of up-land soil were higher than those of paddy soil. 3) There was no difference in the organochlorine residue levels between land-readjusted paddy soil and natural paddy soil.

• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.11-15
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• 1998

Carbofuran was incubated for four weeks in five types of paddy soil samples at $25^{\circ}C$. The soil samples prepared in the study were as follows : control soil, sterilized soil, 10% cellulose added soil, 10% cellulose and 1% ferrous sulfate added soil, and 10% cellulose and 1% magnesium sulfate added soil. The degradation rate of carbofuran was significantly decreased(p<0.05) in sterilized soil.The degradation rate of carbofuran was significantly decreased by addition of cellulose(p<0.05) in femous sulfate added soil and magnesium sulfate added soil(p<0.01).

• Analytical Science and Technology
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• v.21 no.6
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• pp.518-525
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• 2008

Mandipropamid is a new mandelamide-type fungicide to control foliar Oomycete pathogens in some vegetables. An analytical method was developed to determine mandipropamid residues in agricultural commodities using high-performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS). Mandipropamid was extracted with methanol from grape, tomato, green pepper, Chinese cabbage and potato samples. The extract was diluted with saturated sodium chloride solution and distilled water, and dichloromethane partition was followed to recover the mandipropamid from the aqueous phase. Florisil column chromatography was employed to further remove interfering co-extractives prior to HPLC analysis. Reverse-phased HPLC was successfully applied to determine mandipropamid in sample extracts with the detection at its ${\lambda}_{max}$ (223 nm). Overall recoveries of mandipropamid from fortified samples averaged $99.8{\pm}1.7$ (n=6), $89.3{\pm}5.3$ (n=6), $98.7{\pm}2.2$ (n=6), $99.7{\pm}6.8$ (n=6) and $91.1{\pm}3.1$ (n=6) for grape, tomato, green pepper, Chinese cabbage and potato, respectively. Limit of quantification of the method was 0.02~0.04 mg/kg for all samples. A LC/mass spectrometry with selected-ion monitoring was also provided to confirm the suspected residue. The proposed method was reproducible and sensitive enough to determine the terminal residue of mandipropamid in agricultural commodities.

• The Korean Journal of Pesticide Science
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• v.13 no.3
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• pp.133-147
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• 2009

In order to develop the simultaneous analytical method for pesticide residues which ones in soil are rapidly and inexpensively measured by, many analytical methods for individual pesticide residue and several methods for multi-pesticide residues in agricultural commodities and food were reviewed. Various gas chromatographic conditions and pre-treatment procedures were intensively investigated and modified. And then new optimum procedure was established and its proficiency was validated. The response on detectors of simultaneous determination of 180 pesticides out of pesticides used in Korea was tested. The number of pesticides that their limits of detection (LOD) equal or lower than $0.05\;mg\;kg^{-1}$ were 137 pesticides on ECD, 170 pesticides on NPD and 179 pesticides on ECD/NPD integrated. The retention times of most pesticides ranged appropriately between 10 minutes and 40 minutes in the proposed chromatographic conditions. But about 90 pesticides eluded between 20 minutes and 30 minutes and so they were not resolved enough. In partition with dichloromethane, ethyl acetate/hexane (1:1) and ethyl acetate, number of pesticides whose extraction efficiency ranged from 70% to 120%, were 163, 154 and 147, respectively.

• The Korean Journal of Pesticide Science
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• v.4 no.3
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• pp.60-67
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• 2000

This study was conducted to elucidate extraction efficiency by microwave in comparison with Soxhlet for extraction of pesticide residues in dried medical herbs; red-ginseng, white-ginseng, Bupleuri Radix, Angelica gigas Nakai, Rehmannia glutinosa. The acetone extraction by microwave of tolclofos-methyl and quintozene in medical herbs was efficient. The extraction efficiency by microwave with power 45 to 150 watts, extraction time 1 to 5 minutes and solvent volume 30 ml was compared with that of Soxhlet with extraction time 7 hours and solvent volume 150 ml. The extraction efficiency by microwave with extraction time 3 to 5 minutes was similar with extraction time of 7 hours by Soxhlet. When medical herbs spiked with tolclofos-methyl and quintozene was analyzed to how the extraction efficiency of microwave by kind of medical herbs, the extraction efficiency by microwave with extraction time of 3 to 5 minutes was the same as Soxhlet extraction. The optimal condition for extraction of tolclofos-methyl and quintozene in medical herbs by microwave was 45 to 90 watts of power supply, 3 to 5 minutes of extraction time and acetone 30 ml of solvent volume.