• Journal of Environmental Science International
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• v.12 no.4
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• pp.477-480
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• 2003

Pesticides were extracted from samples with 70% acetone and methylene chloride in order, and then cleaned up via open-column chromatography apparatus packed with florisil, and finally analyzed simultaneously the organochlorine and pyrethroid pesticides using GC(ECD). An ultra-2 fused silica capillary column was used to separate and identify the products. The resolution between the last isomeric peak of cypermethrin(59.987min) and the first isomeric peak of flucythrinate(60.043min) was not satisfactory. The last isomeric peak of fenvalerate(62.344min) and the first isomeric peak of fluvalinate(62.397min) were overlapped. Recoveries of soybean sample fer the most pesticides were 73.3% to 102.4%. Detection limits were between 0.004 and 0.063 ${\mu}$g/mg when this method was used.

• Journal of Environmental Health Sciences
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• v.23 no.1
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• pp.66-73
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• 1997

This procedure describes the method for gas chromatographic determination of 31 organophosphorus and 28 organochlorine pesticides in 10g of spinach, tomato and onion. After the pesticides were extracted with several solvents, the amount of coextractives and recovery rates of acephate and methamidophos were calculated. Samples for organochlorine pesticides were cleaned up with florisil solid phase extraction columns. NaBH$_4$ was added to onion extracts, which contained sulfur compound. All the concentrated extracts were analyzed by gas chromatography with ECD and NPD. The smallest amount of coextractives resulted from the spinach samples extracted with 5% MeOH in ethyl acetate. 5% EOH in ethyl acetate had the highest extractability for acephate and methamidophos and gave the best overall performance as an extraction solvent. The ability of 5% EOH in ethyl acetate to extract various organophosphorus and organochlorine pesticides from spinach, tomato and onion was examined. Recovery of 59 insecticides ranged from 58.0% to 110.5%. The average recoveries of fortified spinach, tomato and onion were 90.08%, 94.54% and 84.90%, respectively.

• Journal of Applied Biological Chemistry
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• v.43 no.2
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• pp.94-100
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• 2000

An analytical method was developed to determine abamectin and milbemectin residues in apple, pear, and citrus using HPLC with ultraviolet absorption detection. Abamectin and milbemectin were extracted with methanol from apple, pear, and citrus samples. The extract was diluted with saline water and dichloromethane partition was followed to recover the compounds from the aqueous phase. Florisil column chromatography and aminopropyl solid-phase extraction were employed as cleanup methods to remove most of co-extractives from the sample extract. Reverse-phase HPLC using an octadecylsilyl column was successfully applied to separate and quantitate abamectin and milbemectin residues in sample extracts at the wavelength of 245 nm. Recoveries of abamectin and milbemectin from fortified samples ranged 80.4~90.3% and 90.9~96.8%, respectively. Relative standard deviations of the analytical method were less than 10% for both acaricides. Detection limit of the analytical method was 0.003 mg/kg sample for all the analytes. The proposed method was reproducible and sensitive enough to evaluate terminal residues of abamectin and milbemectin in apple, pear, and citrus.

• Journal of Applied Biological Chemistry
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• v.42 no.4
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• pp.191-196
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• 1999

A multiresidue analytical method was developed for eight acaricides including benzoximate, clofentezine, fenazaquin, fenothiocarb, fenpyroximate, hexythiazox, pyridaben, and tebufenpyrad in four major fruits using high-performance liquid chromatography (HPLC). All the confounds were extracted with acetone from apple, pear, grape, and citrus samples. The extract was diluted with saline water, and n-heaxane partition was followed to recover the acaricides. Florisil column chromatography was employed to further purify the sample extract. HPLC with ultraviolet absorption detection, using an octadecylsilyl column under the isocratic mobile phase of acetonitrile/water mixture, was successfully applied to separate and quantitate all the compounds in the purified extract. Recoveries of the eight acaricides from for fortified samples ranged 86.4~97.0%. Relative standard deviations of the analytical method were all less than 10%. Detection limits of the method were in the range of 0.02~0.05 mg/kg. The proposed method was reproducible and sensitive enough to evaluate the terminal residue of the eight acaricides in the fruit harvest.

• Journal of Environmental Science International
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• v.12 no.10
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• pp.1117-1120
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• 2003

Pesticides were extracted from samples with 70% acetone and methylene chloride in order, and then cleaned up via open-column chromatography apparatus packed with florisil, and finally analyzed simultaneously the organophosphorus pesticides using GC/NPD. Ultra-2 and Ultra-1 fused silica capillary columns were used to separate and identify the products. Recovery of most analytes from soybean sample, taken from pesticide residues well, was greater than(80%) for all except(6) analytes. This method can simultaneously determine multiple pesticides with a high degree of accuracy and precision.

• Preventive Nutrition and Food Science
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• v.4 no.4
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• pp.270-275
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• 1999

Radiation-induced hydrocarbons and 2-alkylcyclobutanones are formed from the fatty acids of irradiated fats. Peanuts were irradiated with a dose of 0.1∼10 kGy. The method consists of the extraction of fat from peanuts, separation of hydrocarbons and 2-alkylcyclobutanones with florisil column chromatography and identification of hydrocarbons by the GC/MS method and 2-alkylcyclobutanones by GC/MS/selected ion monitoring (SIM). Concentrations of hydrocarbons and 2-alkylcyclobutanones were linearly increased with the dose levels of radiation. The major hydrocarbons in the irradiated peanut samples were 8-heptadecene and 1,7-hexadecadiene from oleic acid and 6,9-heptadecadiene and 1,7,10-hexadecatriene from linoleic acid. 2-(5'-Tetradecenyl)cyclobutanone, one of 2-alkylcyclobutanones, was the highest amount in the irradiated peanuts. Radiation-induced hydrocarbons in the peanuts were detected at doses of 0.5 kGy and over, and radation-induced 2-alkylcyclobutanones were detected at doses of 1 kGy and over. These compounds were not confirmed in unirradiate peanuts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1109-1115
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• 1997

Hydrocarbons were analyzed in irradiated beef, pork, dried and seasoned beef, dried anchovy, dried squid, dried shrimp, and fish paste to determine whether the hydrocarbons can be used as markers for detecting post-irradiation of the imported meat and fish products. The samples were irradiated at 0.5, 1, 3, and 6 kGy. Fat was extracted with hexane, and hydrocarbons were separated from the fat through Florisil column. The hydrocarbons were analyzed with GC. Hydrocarbons 15:0, 16:1, 17:1, 16:2, 17:2, and 16:3 in beef and pork, 17:1, 16:2, and 17:2 in dried and seasoned beef, 16:2 in dried anchovy, 16:1 and 17:1 in dried squid, 16:1, 17:1, and 16:2 in dried shrimp, and 16:1, 16:2, and 16:3 in fish paste were detected in the irradiated samples, but not in the unirradiated, so that the hydrocarbons may be used as makers for detecting post-irradiation of each item.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.195-203
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• 2015

Quintozene, pentachloronitrobenzene (PCNB) is a contact fungicide for control of soilborne phytopathogenic fungi during cultivation of diverse crops. It was introduced to agricultural use around 1930's as a substitute for mercurial disinfectants. Although quintozene had been first registered in Korea on 1969. However, now it was banned to use due to its high residue levels in selected harvest products. Also, high possibility is expected that the residue may be contained in imported agricultural commodities as it is still used widely over the world. Therefore, this study was conducted to establish a determination method for quintozene residue in crops using GC/ECD/MS. Quintozene residue was extracted with acetonitrile 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 n-hexane partition was followed to recover quintozene from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The quintozene was quantitated by GLC with ECD, using a DB-1 capillary column. The crops were fortified with quintozene at 3 levels per crop. Mean recoveries ranged from 79.9% to 102.7% in five representative agricultural commodities. The coefficients of variation were less than 4.3%. Quantitative limit of quintozene was 0.004 mg/kg in representative five crop samples. A GC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of quintozene in agricultural commodities.

• Food Science and Preservation
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• v.21 no.6
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• pp.859-865
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• 2014

This study was conducted to analyze the hydrocarbons and 2-alkylcyclobutanones as marker compounds in walnuts after the walnuts' exposure to ${\gamma}$ irradiation. The samples were irradiated with gamma rays at 0, 1, 3, 5, 7, and 10 kGy doses. The lipids were extracted via soxhlet extraction using hexane, and were separated by florisil column and identified via gas chromatography / mass spectrometry (GC/MS). The hydrocarbons that were detected were 8-heptadecene ($C_{17:1}$) and 1,7-hexadecadiene ($C_{16:2}$) from oleic acid and 8,11-heptadecadiene ($C_{17:2}$) and 1,7,10-hexadecatriene ($C_{16:3}$) from linoleic acid. The 2-alkylcyclobutanones that were detected were 2-dodecylcyclobutanone (DCB) from palmitic acid, 2-tetradecylcyclobutanone (TCB) from stearic acid, 2-(5'-tetradecenyl)cyclobutanone (TECB) from oleic acid, and 2-(5',8'-tetradecadienyl)cyclobutanone (5',8'-TCB) from linoleic acid. The correlation between the irradiation dose and the concentrations of the hydrocarbons and 2-alkylcyclobutanones in the walnuts was found to be linear. The radio-induced hydrocarbons and 2-alkylcyclobutanones were clearly detected in the irradiated walnuts at 1 kGy and above, but not in the non-irradiated ones. The major hydrocarbons obtained after irradiation were 8-heptadecene from oleic acid and 8,11-heptadecadiene and 1,7,10-hexadecatriene from linoleic acid, and the major 2-alkylcyclobutanones were TECB from oleic acid and 5',8'-TCB from linoleic acid. Therefore, these major compounds were concluded to be the marker compounds for determining the irradiated and non-irradiated samples.

• Analytical Science and Technology
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• v.25 no.6
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• pp.364-369
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• 2012

Isotianil is a novel fungicide which induces systemic acquired resistance in plants. It has excellent preventive effects as low dosages against rice blast which is one of the most serious diseases in rice. The Maximum Residue Limit (MRL) of Isotianil in republic of korea was set to 0.1 mg/kg in rice, so it is necessary to determine levels of Isotianil residues in agricultural commodities for controlling food safety. Therefore, The purpose of this study was to develop analytical method for the determination of isotiical residues in agricultural commodities using GC-NPD/MSD. Isotianil was extracted with acetonitrile from apple, chinese cabbage, hulled rice, mandarin, pepper, and soybean. The extract was diluted with saline water, and then dichloromethane partition was followed to recover this fungcide from the aqueous phase. A solid phase extraction with Florisil cartridge was additionally employed for final clean up. Isotianil was analyzed and quantitated by GC-NPD and confirmed by GC-MSD. Average recovery of Isotianil ranged from 70.0 to 103.9% in six representative agricultural commodities with relative standard deviations less than 10%, and limit of quantification (LOQ) was 0.05 mg/kg.