• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.501-505
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• 2007

Organophosphorus hydrolase (OPH) expressed from recombinant Escherichia coli was used to biodegrade organophosphate insecticide coumaphos which has a very high toxicity in mammalian cells. To improve the productivity of OPH, the effects of nonionic surfactants (Tween 20, PEG 1000) and organic solvents, such as glycerol, propanol, and ethanol, were investigated in the strain culture. The maximum OPH was produced when the 0.25% of Tween 20 and 0.5% of glycerol were added to the medium. As the OPH obtained from disrupt-cell process by ultrasound treatment was used, the biodegradation efficiencies of 0.2, 0.5, 1.0 and 2.0 mM coumaphos were 100, 88, 84 and 78%, respectively. A novel method developed in this study could be applied to the biodetoxification technology in the contaminated region with various coumaphos concentration.

• Korean journal of food and cookery science
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• v.16 no.5
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• pp.410-415
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• 2000

This study was performed to study tile organophosphorus pesticides residues removal effect of rice and Korean cabbage. Four organophosphorus pesticides(EPN, diazinon, fenithrithion, phenthoate) were artificially added to rice and Korean cabbage. Then they were washed with water and cooked differently to analyze the amount of pesticides residues reduced. The result of the study were as following; 1. The removal rate of pesticides residue on rice was 15.5∼35.4% an[ the amount of washing water was more influential in removal rate than number of washing. 2. The removal rate of pesticides residues through cooking processes after rice washing was 72.1∼77.8%. 3. The removal rate of pesticides residues through washing and cooking processes on the Korean cabbage were 18.4∼41.0%, 22.8∼92.7%. 4. As the amount of washing water of Korean cabbage increase, pesticides removal effect was higher. 5. Squeezing out the washed water from the cabbage increased pesticides removal rate.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.929-935
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• 2007

The objective of this study was to develop a rapid, simple, and qualitative acetylcholinesterase (AChE)- detection kit, based on a modification of the Ellman and ELISA methods, for the detection of organophosphorus (OP) and carbamate (CB) pesticide. The developed kits were used to screen a large number of agricultural samples (spiked and real) for OP and CB pesticide residues. AChE was extracted from the heads of honeybees (Apis mellifera L.) using Triton X-100, and was purified through 3 steps: diethylaminoethylcellulose chromatography (DEAE), affinity chromatography and membrane filtering, and Mono-Q column chromatography. Epoxy-activated Sepharose 6B affinity chromatography was used for large-scale purification. The presence of OP and CB pesticide residues in agricultural samples was assayed on the basis of AchE inhibition value. The presence (6 bands) or absence of some colored bands on the test line indicated a negative or positive result, respectively. The limits of detection for measured organophosphorus (OP) and carbamates (CB) pesticide residues in standard pesticide solutions and fortified samples were ranged from 0.50 to 2.50 ppm and 0.50 to 4.75 ppm, respectively.

• Korean Journal of Environmental Agriculture
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• v.15 no.2
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• pp.246-261
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• 1996

Organophosphorus pesticides, which are an important part of synthetic pesticides in current use contain sulfur atom in their molecules and can be activated or detoxified by environmental and/or biological metabolism. Among the related metabolic reactions, oxidative processes are particularly important with their final products and the study on the reactive intermediates formed in those reactions is essential to elucidate the metabolic pathways and mechanisms and to understand the toxicological properties. This review dealt with the reactive intermediates formed in various reactions from the structural and mechanistic point of view for organophosphorus pesticides and related compounds.

• Journal of Preventive Medicine and Public Health
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• v.23 no.2 s.30
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• pp.194-200
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• 1990

The paraoxonase (E. C. 3.1.1.2) is a major enzyme to detoxicate the organophosphorus and carbamate which are the most widely used as the agricultural spraying insecticides. To investgate the distributions of plasma paraoxonase activity and the factors affecting the enzyme activity, the plasmas of 945 Korean rural population were analysed with the modified Krisch's direct sphectrphotometry method. Three indices of the enzyme activity - basal activity, stimulated activity (by NaCl), % stimulation - were obtained from the analysis. Three indicies suggested unimodal distributions, so we couldn't identify the low activity group risk group to organophosphorus & carbamate insecticides poisoning. There is no significant relation between 3 actvity indicies and sex, age, or history of insecticide use (p>0.05). The basal activity and the stimulated activity have significant relationship and high coefficient of determination with the activities of their parents ($r^2$=0.30, 0.24 ; p<0.05), but the % stimulation does not ($r^2$=0.02 ; p<0.05). These results suggest that the activity of paraoxonase is determined mainly by the genetic factor.

• Journal of Sensor Science and Technology
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• v.23 no.1
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• pp.35-41
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• 2014

Microbes have been used extensively in various fields of researches and industries but has not been used widely for microfluidic biosensor applications because it is difficult to immobilize properly to a small space. Therefore, we developed a microbial immobilization method for microfluidic devices using single-walled nanotubes and dielectrophoretic force. Single-walled nanotubes and Escherichia coli were aligned between two cantilever electrodes by a positive dielectrophoretic force resulting in a film of single-walled nanotubes with attached Escherichia coli. The optimal condition of film formation without a cell lysis was investigated. Diameter of single-walled nanotubes and electric field (intensity and duration of application) had an effect on the cell viability. On the other hand, the cell concentration of the suspension did not affect the cell viability. Paraoxon was detected using single-walled nanotubes film with attached Escherichia coli that expressed organophosphorus hydrolase. This film which is suspended from the substrate showed faster response time than sensors that are not suspended from the substrate.

• Journal of Korean Society on Water Environment
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• v.18 no.4
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• pp.421-433
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• 2002

This study was conducted to develope a simple, rapid and solvent-free solid-phase microextraction(SPME) procedure for extracting three organochlorine, one triazine and nine organophosphorus pesticides from water. The optimal conditions of SPME for analyses of organochlorine pesticides were obtained at $250^{\circ}C$ of desorption temperature, 45 minutes of equilibrium time, pH 6 and NaCl 0% addition using $100{\mu}m$ polydimethylsiloxane fiber and those of triazine and organophosphorus pesticides were obtained at $270^{\circ}C$ of desorption temperature, 60 minutes of equilibrium time, pH 6 and NaCl 0% addition using $100{\mu}m$ polydimethylsiloxane fiber. This method showed good lineality for organochlorine pesticides between 0.0001 and $10{\mu}g/L$ with regression coefficients ranging 0.9986~0.9992 and for triazine and organophosphorus pesticides between 0.01 and $10{\mu}g/L$ with regression coefficients ranging 0.9867~0.9998.

• Korean Journal of Pharmacognosy
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• v.32 no.3 s.126
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• pp.200-211
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• 2001

This study was carried out to determine the 11 organochlorine, 7 organophosphorus residual pesticides in 251 crude drugs. These residual pesticides in herbal drugs were extracted with acetonitrile and the extracts were cleaned up via LC-florisil solid phase extraction column. The prepared samples were assayed for pesticide residues using GC-ECD, NPD with capillary column and identified by GC-MSD. Recoveries were $63.9{\sim}111.5%$ in the organochlorine pesticides and $69.8{\sim}92.4%$ in the organophosphorus pesticides, and detection limits were $0.001{\sim}0.65\;ppm$ in the organochlorine pesticides and $0.0009{\sim}0.0074\;ppm$ in the organophosphorus pesticides. Pesticide residues were detected in 9 cases.

• Analytical Science and Technology
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• v.6 no.1
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• pp.93-106
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• 1993

Fragmentation patterns on electron impact of 8 chlorinated organophosphorus pesticides were investigated. In most cases, characteristic ions could e identified and the peak clusters due to the $^{35}Cl$ and $^{37}Cl$ isotopes in the fragment ions were found to be highly characteristic. The fragmentation patterns of phosphorus moiety were coincident with previous report in the aspect of mechanism.

• Food Science and Biotechnology
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• v.15 no.1
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• pp.57-62
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• 2006

Six organophosphorus, one organochlorine, and three synthetic pyrethroid pesticides were analyzed for their residues during washing and hot-air drying of red peppers conducted in the production of powder. The residue ratio in organophosphorus pesticides was 33% in chlorpyrifos, 31 % in diazinon, 50% in methidathion, 80% in EPN, 28% in fenitrothion, and 60% in profenofos. The ratio in pyrethroids was 109% in cypermethrin, 102% in deltamethrin, and 106% in fenvalerate. That in organochlorine was 56% in ${\alpha}$-endosulfan and 90% in ${\beta}$-endosulfan. The results were greatly different between organophosphorus and pyrethroid pesticides. UV irradiation along with hot-air drying brought about a remarkable reduction of the residues, up to 70% as compared with hot-air drying only. The removal effect was most remarkable in pyrethroids, which are hardly removed by hot-air drying. The color of the pepper was not changed during UV irradiation. The use of oxidizing agents such as hydrogen peroxide or chlorine dioxide during washing did not show a remarkable removal of residues. The residue ratio was not affected whether the pesticide is contaminated artificially or naturally.