• Korean Journal of Environmental Agriculture
• /
• v.8 no.1
• /
• pp.7-16
• /
• 1989

Application of steam distillation on the analysis of pesticide residue in soil, water and crops was studied using the nitrogen distillation apparatus. Most pesticides which were extracted by organic solvents could be analyzed by the steam distillation method. For instance, distillations of PCNB, ${\gamma}-BHC$, ${\alpha}-or$ ${\beta}-endosulfan$, IBP, diazinon, fenthion, fenitrothion, alachlor, butachlor, pretilachlor, metolachlor, pendimethalin, benthiocarb and molinate were possible, but not simazine, atrazine and nitrofen. The optimum volume of distillate for a sufficient extraction of pesticide varied according to kind of pesticide. In general, the volume needed was little for carbamate, but much more for organochlorine. When the definite amount of distillate was obtained and then the condenser was washed by acetone, the optimum volume of distillate was less. Using the steam distillation method, the amount of organic solvent needed for one extraction of pesticide from soil, water and vegetable was less than the conventional solvent extraction method, and the analytical procedure became simpler. The process of concentration and clean up was mostly unnecessary, although a ghost peak was apparent in the gas chromatogram according to the kind of materials distilled.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.170-174
• /
• 2008

Recently, a problem related to the thermal management in portable electronic and telecommunication devices is becoming issued. That is due to the trend of slimness of the devices, so it is not easy to find the optimal thermal management technology for the devices. From now on, a pressed circular type cooling device has been mainly used, however the cooling device with thin thickness is becoming needed by the inner space constraint. In the present study, the silicon and metal flat plate type cooling device with the separated vapor and liquid flow path was designed and fabricated. Through the experimental study, the normal isothermal characteristic by vapor-liquid phase change was confirmed and the cooling device with 70mm of total length showed 6.8W of the heat transfer rate within the range of $4{\sim}5^{\circ}C$/W of thermal resistance. In the meantime, the metal cooling device was developed for commercialization. The device was designed to have all structures of evaporator, vapor flow path, liquid flow path and condenser in one plate. And an envelope of that could be completed by combining the two plates of same structure and size. And the simplicity of fabrication process and reduction of manufacturing cost could be accomplished by using the stamping technology for fabricating large flow paths relatively. In the future, it will be possible to develop the commercialized cooling device by revising the fabrication process and enhancing the thermal performance of that.

• Food Science and Preservation
• /
• v.15 no.1
• /
• pp.66-73
• /
• 2008

Response surface methodology (RSM) was applied for monitor the yields of desirable substances from fig (Ficus carica L) under different extraction conditions. The maximum yield was 66.46% at 22.08 mL/g of solvent to sample ratio, $90.59^{\circ}C$ extraction temperature and 148.04 min extraction time. The maximum total phenolics was $121.31{\mu}g/mL$ at 17.87 mL/g, $98.82^{\circ}C$, and 130.80 min. The maximum electron donating ability was 54.09% at $121.31{\mu}g/mL$, 18.13 mL/g, and $98.81^{\circ}C$. The maximum value of protease activity was 54.51 unit/min at 17.45 mL/g, $99.01^{\circ}C$, and 131.43 min. In addition, the maximum value of reducing sugar content was 19.14 mg/mL in 22.66 mL/g, $86.30^{\circ}C$, and 153.59 min. The optimum conditions estimated by RSM for maximal extraction of the effective components were $17{\sim}25$ mL/g of solvent to sample ratio, $80{\sim}100^{\circ}C$ of extraction temperature, and $100{\sim}170$ min of extraction time.

• Journal of Food Hygiene and Safety
• /
• v.29 no.4
• /
• pp.285-291
• /
• 2014

Saflufenacil is a low-volatile and uracil-based herbicide. This herbicide is used for pre-and post-emergence control of major broadleaf weeds. The objective of present study was to develop and validate an analytical method for saflufenacil determination in agricultural products for ensuring the food safety. The saflufenacil residues in samples were extracted with acetone, dichloromethane, and then purified with silica and graphitized carbon cartridge. The purified samples were analyzed by HPLC-UVD and confirmed with LC-MS. The linear range of saflufenacil was $0.1{\sim}5.0{\mu}gmL^{-1}$ with the correlation coefficient (r) = 0.999. Average recoveries of saflufenacil ranged from 80.5% to 110.2% at the spiked level of $0.02{\sim}0.5mgkg^{-1}$, while the relative standard deviation was 0.3~7.3%. In addition, the limit of detection and limit of quantification were 0.005 and $0.02mgL^{-1}$, respectively. Furthermore, an interlaboratory study among three labs was conducted to validate the method, and the results were satisfactory.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.6
• /
• pp.1089-1094
• /
• 2011

To treat non-point source pollution in Juam lake, removal efficiencies of pollutants were investigated in Bongsan constructed wetlands (CWs) at different treatment time, stages and wastewater loads. The constructed wetlands consisted of forebay, $1^{st}$ and $2^{nd}$ wetlands. The concentrations of BOD, SS, T-N, and T-P in inflow were $1.87mg\;L^{-1}$, $1.62mg\;L^{-1}$, $11.47mg\;L^{-1}$, and $4.40mg\;L^{-1}$, respectively. The removal rates of BOD, SS, T-N, and T-P in Bongsan CWs were 26, 18, 16 and 9%, respectively. The removal rates of BOD and T-N were higher than those for SS and T-P. The amounts of pollutant removal in Bongsan CWs were higher in the order of forebay > $1^{st}$ wetland > $2^{nd}$ wetland for BOD, forebay > $2^{nd}$ wetland > $1^{st}$ wetland for SS, $1^{st}$ wetland > forebay > $2^{nd}$ wetland for T-N and $2^{nd}$ wetland > forebay > $1^{st}$ wetland for T-P.

• Korean Journal of Breeding Science
• /
• v.49 no.4
• /
• pp.390-395
• /
• 2017

A new small red bean cultivar, 'Geomguseul', was artificially crossed between 'Chilbo' and 'SA8412-3-1-4-3-3-2-3' in 1998, fixed excellent agronomic characters by pedigree breeding method, and selected for the further trials with the name of 'Miryang 10'. It was prominent and showed good result, such as high grain quality, lodging resistance, and high-antioxidant activity in the regional adaptation yield trials (RYT) for three years from 2009 to 2011 and released for the public consumption as the name of 'SA9801-24-4-3-1' in 2011. 'Geomguseul' has a semi-determinate growth habit, yellow flower, green embryonic axis, black seed coat, white hilum, and small spherical seed (12.2 grams per 100 seeds). The average yield of 'Geomguseul' was 2.01 MT/ha in the regional yield trials (RYT) carried out for three years from 2009 to 2011 which was a little higher than that (1.98 MT/ha) of the check variety, 'Chungju'.

• Korean Journal of Environmental Agriculture
• /
• v.32 no.1
• /
• pp.70-77
• /
• 2013

BACKGROUND: Nitroxoline is an antibiotic agent. It is used for the treatment of the second bacterial infection by the colibacillosis, salmonellosis and viral disease of the poultry. When the nitroxoline is indiscreetly used, the problem about the abuse of the antibiotics can occur. Therefore, this study presented the residue analytical method of nitroxoline in food for the safety management of animal farming products. METHODS AND RESULTS: A simple, sensitive and specific method for nitroxoline in chicken muscle by high performance liquid chromatograph with PDA was developed. Sample extraction with acetonitrile, purification with SPE cartridge (MCX) were applied, then quantitation by HPLC with C18 column under the gradient condition with 0.1 % tetrabutylammonium hydroxide-phosphoric acid and methanol was performed. Standard calibration curve presented linearity with the correlation coefficient ($r^2$) > 0.999, analysed from 0.02 to 0.5 mg/L concentration. Limit of quantitation in chicken muscle showed 0.02 mg/kg, and average recoveries ranged from 72.9 to 88.1 % in chicken muscle. The repeatability of measurements expressed as coefficient of variation (CV %) was less than 12 % in 0.02 and 0.04 mg/kg. CONCLUSION(S): Newly developed method for nitroxoline in chicken muscle was applicable to food inspection with the acceptable level of sensitivity, repeatability and reproducibility.

• Progress in Medical Physics
• /
• v.17 no.2
• /
• pp.83-88
• /
• 2006

Purpose: We Investigated to achieve high resolution magnetic resonance (MR) Imaging and spectra of human skin in vitro with using a 14.1 T MRI/MRS system, and to evaluate the hydration effect of a moisturizer by measuring the skin's water concentration. Materials and Methods: We used the Brukrer 14.1 T MRI/MRS system with a vertical standard bore that was equipped with a DMX spectrometer gradient system (200 G/cm at a maximum 40 A), RF resonators (2, 5 and 10 mm) and Para Vision software. Spin echo and fast spin echo pulse sequences were employed for obtaining the high resolution MR images. The 3D-localized point resolved spectroscopy (PRESS) method was used to acquire the MR spectra. Results: The high resolution MR images and spectra of human skin in vitro were successfully obtained on a 14.IT system. The water concentration of human skin after applying a moisturizer was higher than that before applying a moisturizer. Conclusions: The present study demonstrated that the high-resolution MR images and spectra of human skin from a high field MRS instrument could be applicable to evaluating the hydration state of the stratum corneum.

• Analytical Science and Technology
• /
• v.27 no.5
• /
• pp.234-242
• /
• 2014

Imicyafos which is a nematicide for controlling root-knot nematodes has been registered in the Republic of Korea in 2012, and the maximum residue limits of imicyafos are set to watermelon and korean melon as each 0.05 mg/kg. Extremely reliable and sensitive analytical method is required for ensuring food safety on imicyafos residues in agricultural commodities. Imicyafos residues in samples were extracted with acetone, partitioned with hexane and dichloromethane, and then purified with florisil. The purified samples were analyzed by HPLC-UVD and confirmed with LC-MS. Linear range was between 0.1~5 mg/kg with the correlation coefficient ($r^2$) 0.99997. Average recoveries of imicyafos ranged from 77.0 to 115.4% at the spiked levels of 0.02 and 0.05 mg/kg with the relative standard deviations of 2.2~9.6%. Limit of detection and quantification were 0.005 and 0.02 mg/kg, respectively. An inter-laboratory study was conducted to validate the determination method in depth, and the results were satisfactory. All of the validation results revealed that the developed analytical method in this study is relevant for imicyafos determination in agricultural commodities and will be used as an official analytical method.