• Korean Journal of Environmental Agriculture
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• v.37 no.1
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• pp.57-65
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• 2018

BACKGROUND: An analytical method was developed using HPLC-UVD/MS to precisely determine the residue of flusulfamide, a benzenesulfonamide fungicide used to inhibit spore germination. METHODS AND RESULTS: Flusulfamide residue was extracted with acetone from representative samples of five raw products which comprised apple, green pepper, Kimchi cabbage, hulled rice, and soybean. The extract was diluted with large volume of saline water and directly partitioned into dichloromethane to remove polar co-extractives in the aqueous phase. For the hulled rice and soybean samples, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. On an octadecylsilyl column in HPLC, flusulfamide was successfully separated from co-extractives of sample, and sensitively quantitated by ultraviolet absorption at 280 nm with no interference. Accuracy and precision of the proposed method was validated by the recovery experiment on every crop sample fortified with flusulfamide at 3 concentration levels per crop in each triplication. CONCLUSION: Mean recoveries ranged from 82.3 to 98.2% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of flusulfamide was 0.02 mg/kg as verified by the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring technique was also provided to clearly identify the suspected residue.

• The Korean Journal of Pesticide Science
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• v.14 no.1
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• pp.37-48
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• 2010

The diacylhydrazine insecticides, methoxyfenozide, chromafenozide and tebufenozide are new-generation insecticides. These insecticides induce premature molting and cause the death of insects by mimicking their hormone. Also, these insecticides have already been widely used for vegetables planting in worldwide. Highperformance liquid chromatography (HPLC) is the most widely used procedure for determination of each compound residues in crops. However, simultaneous analysis method of these diacylhydrazine insecticides was not reported. The purpose of this study is to develop a simultaneous determination procedure of methoxyfenozide, chromafenozide and tebufenozide residue in crops using HPLC-UVD/MS method. These insecticide residues were extracted with acetone from representative samples of five raw products which comprised hulled rice, soybean, apple, pepper, and Chinese cabbage. The extract was diluted with saline water, and dichloromethane partition was followed to recover these insecticides from the aqueous phase. Florisil column chromatography was additionally employed for final cleanup of the extracts. The analytes were quantitated by HPLCUVD/MS, using a $C_{18}$ column. The crops were fortified with each insecticide at two levels per crop. Mean recoveries ranged from 89.0 to 104.8% in five representative agricultural commodities. The coefficients of variation were less than 3.9%. Quantitative limits of methoxyfenozide, chromafenozide and tebufenozide were 0.04 mg/kg in crop samples. A HPLC-UVD/MS with selected-ion monitoring was also provided to confirm the suspected residues. The proposed simultaneous analysis method was reproducible and sensitive enough to determine the residues of methoxyfenozide, chromafenozide and tebufenozide in agricultural commodities.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1018-1023
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• 1998

Hydrocarbons in dry soup base and its ingredients in instant noodle were analyzed to determine whether the analysis of hydrocarbons is a potential method to detect post-irradiation of the soup base. Soup base ingredients were irradiated individually, irradiated before mixing, or mixed after irradiation. Lipids were extracted with hexane and hydrocarbons were separated from the lipids through Florisil column. The hydrocarbons were analyzed with GC. Hydrocarbons C17:2, C16:3, C17:1, and C16:2 were detected in palm oil, red pepper powder, and sesame seeds irradiated at 10 kGy, but not in unirradiated ones. C17:2, C16:3, C17:1, and C16:2 were not detected in the soup base mixture of unirradiated ingredients. The four hydrocarbons were detected in the soup base mixture using irradiated palm oil or sesame seeds. In the mixture using irradiated red pepper powder, C17:2 and C16:3 were detected. When the soup mixture was irradiated after mixing unirradiated ingredients, C17:2, C17:1, and C16:2 were detected in the sample irradiated at 1 kGy, and C17:2, C16:3, C17:1, and C16:2 were in large amounts at 5 and 10 kGy.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.309-317
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• 2015

BACKGROUND: An analytical method was developed using GC-ECD/MS to precisely determine the residue of fipronil, a phenylpyrazole insecticide used to control a wide range of foliar and soil-borne pests.METHOD AND RESULTS: Fipronil residue was extracted with acetone from representative samples of five raw products which comprised hulled rice, soybean, Kimchi cabbage, green pepper, and apple. The extract was diluted with saline water, and fipronil was partitioned into n-hexane/dichloromethane (20/80, v/v) to remove polar co-extractives in the aqueous phase. Florisil column chromatography was additionally employed for final purification of the extract. Fipronil was separated and quantitated by GC-ECD using a DB-17 capillary column. Accuracy of the proposed method was validated by the recovery from crop samples fortified with fipronil at 3 levels per crop in each triplication.CONCLUSION: Mean recoveries ranged from 86.6% to 106.0% in five representative agricultural commodities. The coefficients of variation were less than 10%. Limit of quantitation of fipronil was 0.004 mg/kg as verified by the recovery experiment. A confirmatory technique using GC/MS with selected-ion monitoring was also provided to clearly identify the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of fipronil in agricultural commodities.

• Journal of the Korean Chemical Society
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• v.39 no.12
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• pp.902-909
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• 1995

Detection limit as well as calibration curves on organophosphorus pesticide(dimethoate, diazinon, parathion-methyl, fenitrothion, malathion) and BHCs were measured for evaluation of utility on qualitative or quantitative analysis of pesticides with ion Trap mass spectrometer and quadrupole mass spectrometer. As ionization source, EI and CI were adopted for qualitative analysis of pesticides by comparison of each fragmentation pattern. At the same time, the utility as trace analysis techniques through scan or selected ion monitoring(SIM) mode was evaluated. With ion trap for all pesticides, detection limit(DL, 1 ${\mu}L$ injection) on scan mode was ranged 0.008∼0.225 ng at signal to noise ratio 3. With quadrupole DL on scan mode was ranged 0.23∼3.1 ng over 0.032∼0.68 ng on SIM mode. The calibration curve with ion trap generated good linearity over 0.99 as correlation coefficient. As clean up procedure, Bio Beads S-X3 was used for the separation of oils from five organophosphorous pesticides in flour extractant showing more than 80% as recovery at most cases. In case of BHCs in jinseng with Florisil column, the recovery of pesticides has been 60% to 90%.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1495-1502
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• 1999

Gamma-irradiated beef and chicken at the dose levels of 0.5 to 10 kGy were subjected to the detection of radiation-induced 2-alkylcyclobutanones whether irradiated or not. Radiation-induced 2-alkylcyclobutanones were extracted from beef and chicken fats, separated by florisil column chromatography and identified with GC/MS method by selected ion monitoring(SIM). When beef and chicken were irradiated, 2-dodecylcyclobutanone, 2-tetradecylcyclobutanone and 2-(5'-tetradecenyl)cyclobutanone were formed from palmitic, stearic and oleic acids. Concentrations of 2-alkylcyclobutanones were linearly increased with the dose levels of irradiation and depended upon the composition of fatty acids in beef and chicken. Radiation-induced 2-alkylcyclobutanones in irradiated beef and chicken were remarkably detected at 1 kGy and over, while these compounds were not detected in non-irradiated samples. The concentrations of radiationinduced 2-alkylcyclobutanones were relatively constant during 6 months.

• Analytical Science and Technology
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• v.16 no.1
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• pp.48-58
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• 2003

The effects of physico-chemical properties of soils on PCBs analysis in Korea was studied Three kinds of extraction solvents(toluene, acetone:hexane, dichloromethane) was selected to apply three different soils. The silicagel, florisil and alumina column cleanup also performed to compare the elution patterns, and three different methods (EPA, Japan, Proposed method in this study) of 62 PCBs also compared the individual peaks recoveries. The solvent average recovery was surveyed the order of toluene, acetone:hexane, dichloromethane as 77.94%, 58.59%, 54.20% for soil A, 53.65%, 80.32%, 68.27% for soil B and 44.52%, 60.35%, 56.36% for soil C, respectively. The average recovery was depended on the soil characters. The highest recoveries of each soil were obtained the toluene for soil A, acetone:hexane for soil B and C. However, the coplanar PCBs was obtained the highest recovery with dichloromethane. Thus, to select the solvent for the analysis of PCBs in solid, the selected compounds have to consider to get good result. The silicagel, florisil, alumina I and alumina II column cleanup process were surveyed the range of 38.73%~98.26%, and the higher chlorinated compounds was obtained the lower recovery compared to the low chlorinated compounds, generally. This results are also consistent with the coplanar PCBs isomers. The compared results of three different countries were obtained the 37.15% for USA, 45.92% for Japan and 44.46% for proposed method in this study.

• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.339-346
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• 2018

Cyanazine is a member of the triazine family of herbicides. Cyanazine is used as a pre- and post-emergence herbicide for the control of annual grasses and broadleaf weeds. This experiment was conducted to establish a determination method for cyanazine, as domestic unregistered pesticide, residue in major agricultural commodities using HPLC-DAD/MS. Cyanazine was extracted with acetone from representative samples of five raw products which comprised apple, green pepper, Kimchi cabbage, hulled rice and soybean. The extract was diluted with saline water and partitioned to dichloromethane for remove polar extractive in the aqueous phase. For the hulled rice and soybean samples, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized florisil column chromatography. On a $C_{18}$ column in HPLC, cyanazine was successfully separated from co-extractives of sample, and sensitively quantitated by diode array detection at 220 nm. Accuracy and precision of the proposed method was validated by the recovery experiment on every major agricultural commodity samples fortified with cyanazine at 3 concentration levels per agricultural commodity in each triplication. Mean recoveries were ranged from 83.6 to 93.3% in five major representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation(LOQ) of cyanazine was 0.02 mg/kg as verified by the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring(SIM) technique was also provided to clearly identify the suspected residue.

• Korean Journal of Agricultural Science
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• v.11 no.2
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• pp.190-193
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• 1984

Extracts of common purslane(Portulaca oleracea L.) showed to possess some antifungal substances which inhibited the mycelial growth of the phytopathogenic fungi tested;Valsa mali, Alternaria kikuchiana and Pyricularia oryzae. These antifungal substances were found to be soluble in methanol and were regarded as kinds of lipid. In order to isolate the antifungal substances, the extracts of common purslane were concentrated by evaporation under reduced pressure and extracted with methanol The methanol solution was subjected to silica gel-florisil column and divided into lipid and non-lipid fractions. Lipid fractions only showed antifungal activity against the fungi tested. The effective substances contained in the extracts of common purslane inhibited not only the mycelial growth but also the spore germination of the fungi.

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.15-23
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• 1999

A multiresidue, simple and rapid isolation technique known as matrix-solid phase dispersoin (MSPD) for the extraction and quantitative gas chromatographic/electron capture detection (GC/ECD) determination of 14 organochlorinated pesticides($\alpha$-BHC, ($\beta$-BHC, ($\gamma$-BHC, aldrin, dieldrin, endrin, heptachlor, ($\alpha$-endosulfan, ($\beta$-endosulfan, endosulfan sulfate, p,p'-DDE, o,p'-DDD, p,p'-DDD, p,p'-DDT) from meat fats. The 14 pesticide were fortified into meat fat(0.5g) and blend with 2g $C_{18}$, $C_{18}$meat fat matrix blend and 2g activated florisil comprise an extraction column from which the pesticides are eluted by adding 8ml acetonitrile. Then 2${\mu}\ell$ of the eluate is analyzed by GC/ECD. Unfortified blank controls are tested similarly. The eluate contained all the pesticide analytes and was free of interfering coextractants. Recovery rate(31.3-500ng/g) were ranged from 80$\pm$4% to 97$\pm$4%. Any organochlorinated pesticides were not detected in 120 samples of beef and pork collected from slaughter houses in Kyeonggi province.