• Journal of Biosystems Engineering
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• v.32 no.2 s.121
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• pp.121-129
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• 2007

This study was conducted to elucidate extraction efficiency by microwave technique in comparison with sonication technique for extraction of insecticide residue in pear. In the analysis of the extraction efficiency of microwave for a pear spiked with imidacloprid, the extraction efficiency by microwave power of 300 W with extraction temperature of $80^{\circ}C$, heating time of 1 to 3 minute was shown to be similar with the extraction time 20 minutes by sonication. The optimal condition. in consideration of economical condition and treatment time, for microwave extraction of imidacloprid in the pear were 300 watts of power supply, $100^{\circ}C$ of extraction temperature, 1 minute of heating time and 10 mL of acetone volume. A new microwave vessel was developed to rapidly process the sample of the insecticide imidacloprid residues in the pear. This vessel was designed to include a reaction chamber and a filtration equipment, and a gathering chamber. The system could curtail a pretreatment time to 21 minutes than sonication and 7.9 minutes than the previous microwave vessel.

• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.152-156
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• 2012

BACKGROUND: This research has investigated the residue patterns of insecticide flubendiamide on three species of peaches with different surface forms, and the residue amounts of them when mixed with a spreader. METHODS AND RESULTS: Pesticide used for field application on peaches was 20% flubendiamide of suspension concentrate(SC) and was sprayed at a recommended rate. The residue amounts of flubendiamide in peach were analyzed by HPLC equipped with UV detector. After the observation with a microscope, the rank of fuzz amount on peach's surface was Kurakatawase, Wolmi in descending order and Cheonhong did not have any fuzz. The residue amounts of flubendiamide were 0.54 mg/kg for Kurakatawase, 0.43 mg/kg for Wolmi and 0.10 mg/kg for Cheonhong, respectively. When flubendiamide was used with a spreader, polyoxy ethylene methylpoly siloxane, the residue amount for Kurakatawase barely changed at 0.55 mg/kg regardless of mixing with a spreader, and at 0.53 mg/kg for Wolmi. In Cheonhong, the residue amount was 0.48 mg/kg, which increased by 4.8 times due to the use of a spreader. CONCLUSION: This result indicates that the residue amounts of flubendiamde were affected by the surface forms of peaches, and in the presence of a spreader the residue amount did not increase in fuzzy species, but was affected greatly for species without fuzz.

• Journal of Biosystems Engineering
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• v.28 no.6
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• pp.505-510
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• 2003

In Korea, due to its broad efficacy as a systemic insecticide, imidacloprid has been widely used in rice paddies to control sucking insects, soil insects, and some chewing insects and in apple orchards to control various insects pests. To quantify the imidacloprid residue concentrations, samples are assayed in vitro using enzyme-linked immunosorbent assays(ELISA). These assays generally require several hours to perform. As a biosensor, a competitive imidacloprid ELISA was modified to measure insecticide concentrations. It was found that a total assay time of 15 min(10-min antibody-antigen binding, and 5-min substrate development) is sufficient for monitoring imidacloprid concentrations. Further work is needed to improve the sensitivity of the measurement protocol.

• Journal of Food Hygiene and Safety
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• v.1 no.2
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• pp.181-186
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• 1986

Organophosphorus insecticide residues were investigated in six kinds of fruits and five kinds of vegetables.The materials used in this experiment were grape, musk melon, apple, peach, plum, apricot, lettuce, green pepper, cucumber, pumpkin and tomato which were collected from June to september 1986 in Seoul. Residual pesticides investigated were Diazinon, Parathion, MEP (Fenitrothion), Malathion, EPN, MPP (Fenthion), PAP (Phenthoate) and Dimethoate and all samples were analysed by gas chromatographic technique with NPD (Nitrogen Phosphorus Detector). No sample was found to approach proposed national maximum residue limits in Korea.

• Current Research on Agriculture and Life Sciences
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• v.11
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• pp.101-110
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• 1993

The residues of combined insecticide of polynactin complex(tetranactin) and BPMC were determined to establish an index for the safety use to apple. Evaluation was made on residual concentration of tetranactin and BPMC in apple as a function of application frequency and date when the combined insecticide of tetranactin and BPMC was sprayed into apple. Their persistence in soil were also studied under the field and laboratory conditions. Recovery percentage from apple was ranged from 74.0 to 77.5 in tetranactin, 87.1 to 83.6 in BPMC, those from soil was 82.3 to 88.4 in tetranactin, 83.6 to 887.1 in BPMC. The minimum detectable limits of tetranactin and BPMC were 0.01ppm in apple pulp and 0.03ppm in apple peel and soil. The residue percentage of tetranactin and BPMC in the peel and pulp part of apple was about 96 in peel part by five sprays up to 3th day before harvest. The residues of tetranactin and BPMC in apple are proved to 0.39ppm and 0.75ppm by five sprays up to 30days before harvest. Maximum residue limit(MRL) of BPMC for fruits was established of 0.3ppm in Environment Protection Agency of Korea, and thus it is suggested that the preharvest intervals of combined insecticide for apple could be 30 days with twice spray. The half life of tetranactin in soil under field and laboratory conditions was 6.9 and 24.4 days, and in case of BPMC was 6.3 and 23.2 days, respectively.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1038-1046
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• 2008

This study was carried out to develop a small-sized biosensor based on surface plasmon resonance (SPR) for the rapid identification of insecticide residues for food safety. The SPR biosensor module consists of a single 770 nm-light emitting diodes (LED) light source, several optical lenses for transferring light, a hemisphere sensor chip, photo detector, A/D converter, power source, and software for signal processing using a computer. Except for the computer, the size and weight of the sensor module are 150 (L)$\times$70 (W)$\times$120 (H) mm and 828 g, respectively. Validation and application procedures were designed to assess refractive index analysis, affinity properties, sensitivity, linearity, limits of detection, and robustness which includes an analysis of baseline stability and reproducibility of ligand immobilization using carbamate (carbofuran and carbaryl) and organophosphate (cadusafos, ethoprofos, and chlorpyrifos) insecticide residues. With direct binding analysis, insecticide residues were detected at less than the minimum 0.01 ppm and analyzed in less than 100 sec with a good linear relationship. Based on these results, we find that the binding interaction with active target groups in enzymes using the miniaturized SPR biosensor could detect low concentrations which satisfy the maximum residue limits for pesticide tolerance in Korea, Japan, and the USA.

• The Korean Journal of Pesticide Science
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• v.4 no.4
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• pp.35-39
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• 2000

In order to develop the indicators of environmental impact of pesticide, its actual usage in paddy rice was surveyed, and usage trends of individual pesticides were evaluated. The tendency of pesticide use indicated insecticide 43%, herbicide 29%, fungicide 27% and top ranking item in insecticide, herbicide and fungicide was carbofuran, molinate + pyrazosulfuran-ethyl, IBP. The usage statistics of formulation types showed GR>DP>WP>EC>FG>SP. Pesticide usage(a.i.) per hectare was 7.13kg and total usage for paddy rice was estimated at 8,387 M/T. In the result of comparison of fact-usage with pesticide consumption reported in 1998, the fitness was 94.7% for fungicide, 84.3% for insecticide, 77.8% for herbicide. The result of monitoring pesticide residue of unpolished-rice sampled from farm house of survey indicated 0.14 ppm(BPMC), 0.16 ppm(Isoprocarb), 0.17 ppm(Isoprothiolane). In case of rice straw, the residue level was 0.27 ppm(Isoprothiolane), 0.28 ppm(IBP), 0.39 ppm(Carbofuran). The residue levels of pesticides were below MRLs.

• Journal of Food Hygiene and Safety
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• v.12 no.1
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• pp.39-46
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• 1997

Mandarin orange fruits were artificially contaminated with an organophosphorus insecticide phenthoate by dipping and the residue level of phenthoate was investigated during the purification steps of dietary fiber or bioflavonoid. The removal rate of phenthoate at 8 and 0.5 ppm levels was 98% in the total dietary fiber, 99% in the insoluble dietary fiber and 99.8% in the soluble dietary fiber preparations. Kuring the preparation of biflavonoid from peels at a 5 ppm pesticide level, the removal rate was 90% in the intermediate extract and 99.9% in the final extract. In conclusion, phenthoate residues in the peels of mandarin orange were mostly removed during the preparation processes of dietary fiber of bioflavonoid and its residue level would not raise any problem in safety aspects of the purified products.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.84-93
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• 2013

BACKGROUND: This study was carried out to investigate the residual characteristics of insecticides used for Oriental Tobacco Budworm control and to establish the recommended pre-harvest residue limit leading to contribution in safety of paprika production. METHODS AND RESULTS: The recommended Pre-Harvest Residue Limits (PHRLs) of insecticides during cultivation of paprika were calculated from residue analyses of insecticides in fruits 1, 3, 5, 7, 10, 12, 15, 18 and 21 days after treatment. Paprika samples were extracted with QuEChERS method and cleaned-up with amino propyl SPE cartridge and PSA, and insecticide residues were analyzed either by HPLC/DAD or GLC/ECD. The limits of detection were 0.01 mg/kg for 5 insecticides. Average recoveries were $81.3{\pm}1.62%$-$98.3{\pm}1.58%$ of 5 insecticides at fortification levels of 0.1 and 0.5 mg/kg. The biological half-lives of the insecticides were 8.5 days for bifenthrin, 11.8 days for chlorantraniliprole, 16.8 days for chlorfenapyr, 7.1 days for lamda-cyhalothrin and 31.3 days for methoxyfenozide at recommended dosage, respectively. CONCLUSION(S): The pre-harvest residue limits for 10 days before harvest were recommended 1.05 mg/kg, 1.41 mg/kg, 0.93 mg/kg, 2.06 mg/kg and 1.08 mg/kg as bifenthrin, chlorantraniliprole, chlorfenapyr, lamda-cyhalothrin and methoxyfenozide, respectively. This study can provide good practical measures to produce safe paprika fruit by prevention of products from exceeding of MRLs at pre-harvest stage.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1760-1772
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• 2006

Mature acetylcholinesterase (AChE) gene (gm, 1,836 bp) was cloned from the housefly and successfully expressed in the E. coli CodonPlus (DE3) RIL system (GM-E, 72 kDa) with a yield of 1,630 mU/g fresh cells. Using the gm, 10 kinds of mutants were constructed and expressed for enhancing sensitivity to insecticides. The sensitivity of these mutants to five kinds of organophosphate (OP) and three carbamate insecticides was investigated by measuring the apparent bimolecular inhibition constant ($k_i=k_2/K_d$). Surprisingly, the sensitivity of quadruple mutant IGFT was enhanced as much as 7-fold for acephate, 164-fold for demeton-S-methyl, 484-fold for dichlorvos, 523-fold for edifenphos, 30-fold for ethoprophos, 30-fold for benfuracarb, 404-fold for carbaryl, and 107-fold for furathiocarb, compared with that of GM-E, although the sensitivity of each single point mutant was slightly increased. These mutational studies indicated that (i) contradictory to Walsh et al. [39], the residue 327 is the important key residue for enhancing sensitivity as much as the residue 262, (ii) the residue 82 and additional residues of 234, 236, and 585 are also important, and (iii) sensitivity was cooperatively accelerated as the number of strategic mutations increased.