• Korean Journal of Food Science and Technology
• /
• v.52 no.1
• /
• pp.26-30
• /
• 2020

This study was undertaken to determine the characteristics of xanthoangelol, the major chalcone constituent derived from the extracts of different parts of Lespedeza bicolor. Xanthoangelol was isolated from the root extract using column chromatography and used as a standard for quantitative analysis. The structure of the isolated compound was established based on spectroscopic evidence. The HPLC-DAD method was validated for specificity, linearity, precision, accuracy, limit of detection, and limit of quantitation. The calibration curve of xanthoangelol had significant linearity (R²>0.9999). Limit of detection and limit of quantitation 0.018 and 0.059 ㎍/mL, respectively. The relative standard deviation values of precision test, and intra- and inter-day tests were less than 0.22 and 0.40%, respectively. In the recovery test, the accuracy ranged from 98.98-102.78% with RSD values less than 0.13%. The method validation parameters indicate the applicability of the HPLC method for quality control of food or drug formulations containing L. bicolor.

• Applied Biological Chemistry
• /
• v.12
• /
• pp.33-41
• /
• 1969

1. Crude cellulase extracted from wheat bran media of Chaetomium globosum with pH 7.0 McIlvaine buffer was fractionated by precipitation with ammonium sulfate and by treatment with the cellulose powder, DEAE-Sephadex A-25 and Amberite XE-65 (IRC-50) column chromatography. 2. Consquently two cellulases C-1 and C-2 were obtained by cellulose column chromatography. Cellulose C-1 was a powerful CMC-saccharifying and CMC-liquefying activity but cellulose C-2 was stronger CMC-liquefying activity compared to CMC-saccharifying activity and cellulase C-2 had smaller protein than that of cellulose C-1. And cellulose C-2 was fractionated by DEAE-Sephadex A-25 column chromatography into cellulase C-1-1 and cellulose C-1-2. 3. It can be obtained, therefore, that cellulose produced Chaelomium globosum consisted, at least, of three cellulases C-2, C-1-1 and C-1-2. 4. Cellulose C-1-1 was homogenous in the ultraviolet and the ultracentrifuge pattern. And cellulose C-1-1 had enzyme for CMC-saccharifying activity. 5. The optimum pH for the enzyme activity of cellulose C-1-1 was 4.0 in any methods of meas urement reducing sugar and viscosity. The optimum temperature was $40^{\circ}C$ in any methods. 6. The pH stability of cellulase C-1-1 was within pH 5.0 to pH 6.0 at $40^{\circ}C$ and fairly stable in acidic solution. 7. The heat stability was below $50^{\circ}C$ at pH 4.0 and complete heat inactivation of this cellulase occurred at $70^{\circ}C$.

• Economic and Environmental Geology
• /
• v.11 no.3
• /
• pp.89-98
• /
• 1978

Mineralogy, beneficiation, and processes of titanium ores are reviewed from petrographic viewpoints. The most important titanium minerals are ilmenite ($FeTiO_3$) and rutile ($TiO_2$). Ilmenite will play major role :for raw material, because rutile are rapidly diminishing. Thus, there is a need to develope a successful process for producing high grade Ti02 from ilmenite. Commercial, as well as R and D processes to treat more abundant ilmenite ores fall in three general classess: 1. Iron in ilmenite is partially or completely reduced and separated either physically or chemically. 2. Iron is reduced to ferrous state and chemically leached away from the titanium. 3. Ore is treated to make chlorides either selectively or with subsequent separation and purification of $TiC_4$. Routes and efficiencies of these process technologies are primarily influenced by the particular ore deposit to be mined and secondly by environmental considerations. One deposit parameters which influence ilmenite process technologies are: 1. Complexity of microtextures of ilmenite intergrown with Fe-oxide minerals. 2. Composition of concentrates; ilmenites contain minor amounts of substituted Mg, Mn, and V. These elements plus iron and gangue minerals can cause difficulties to complete reactions, substantial acid consumption, difficulties of removing waste solids, and waste disposal problems. Major contributions to be made by petrologists for process optimization are: characterization and interpretation of compositional and physical changes of raw materials and solids derived from process streams. These informations can play significant role in selecting and improving process steps for titania production.

• Journal of Food Hygiene and Safety
• /
• v.35 no.4
• /
• pp.312-318
• /
• 2020

A method using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for neonicotinoid pesticide analysis in agricultural products. Four compounds (imidacloprid, clothianidin, acetamiprid, thiacloprid) were extracted with acetonitrile from agricultural products and cleaned up by NH₂ solid-phase extraction procedure, and eluted with 0.1% formic acid in methanol/dichloromethane (5/95, v/v). The limit of detection and quantification were 0.0001-0.0005 mg/kg and 0.001 mg/kg, respectively. The mean recoveries of neonicotinoid pesticide from agricultural products were in the range of 90.7-100.9% and 94.4-99.8%, as spiked at 0.2 mg/kg and 0.02 mg/kg, respectively. This validation satisfied the national criteria for pesticide analytical methods. In summary, The present method is fast, precise and sensitive enough for the Positive List System (PLS), and we conclude that the method is also suitable for neonicotinoid pesticide determination in a wide range of agricultural products.

• Korean Journal of Food Science and Technology
• /
• v.26 no.2
• /
• pp.162-166
• /
• 1994

A rapid gas chromatographic (GC) profiling method for the simultaneous analysis of volatile and nonvolatile organic acids was applied to alcoholic beverages (white wine, red wine, brandy, and beer). It involves the solid-phase extraction of organic acids using Chromosorb P as the sorbent and diethyl ether as the eluent with subsequent triethylamine treatment. The resulting triethylammonium salts of acids were directly converted to volatile tert.-butyldimethylsilyl derivatives, which were analyzed by dual-capillary column GC and GC-mass spectrometry. From the alcoholic beverages studied, more than 29 organic acids were detected. When the simplified retention infer (RI) spectra of organic acids, and the direct comparisor method between alcoholic beverages and a test sample were attempted to identify a test sample, it was quickly recognized to be a red wine with the 998 ppt match quality value.

• Korean Journal of Optics and Photonics
• /
• v.8 no.1
• /
• pp.31-36
• /
• 1997

We measured refractive indices and thicknesses of SiO$_2$ thin films that have been plated on LCD glass substrate for the purpose of preventing the out-diffusion of sodium ions. The best experimental condition to determine refractive index and thickness of SiO$_2$ thin film by using ellipsometry is searched for, where ⅰ) the film thickness is increased uniformly by 20 $\AA$ from 0 $\AA$ to the period thickness while the angle of incidence is fixed and ⅱ) the angle of incidence is increased uniformly by 1$^{\circ}$ from 45$^{\circ}$ to 70$^{\circ}$ while the film thickness is fixed. We estimated the errors in determining the refractive index and thickness by comparing the measurement error of $\Delta$ and Ψ with the calculated one. The ellipsometric constants of SiO$_2$ thin film on LCD glass substrate are measured at several angle of incidence around the Brewster angle, which is the best angle if the experimental error of ellipsometer is not sensitive to the incident angle. Also the best fit refractive index and thickness of SiO$_2$ thin film to these ellipsometric constants measured at several angle of incidenc eas well as the best fit ones to the SE data are obtained using regressional analysis.

• Polymer(Korea)
• /
• v.32 no.1
• /
• pp.13-18
• /
• 2008

For the evaluation of brominated flame retardants included in polymeric electronic devices, we investigated the extraction methods and solvent systems for four different types of polymers of PC (polycarbonate), PP (polyropylene), PET (poly(ethylene terephthalate)) and PBT (poly(butylene terephthalate)) using different solvent systems of hexane/acetone, THF, toluene, and THF/toluene. In order to compare the extraction efficiency of different methods and solvent systems, the deca-BDE (decabromo diphenyl ether) flame retardant was included in PC, PP, PET and PBT systems and subsequently extracted by soxhlet, ultrasonic, accelerated solvent, microwave and supercritical fluid extraction methods. The amount of the extracted flame retardant was monitored to evaluate the extraction efficiency. The ultrasonic extraction method was found not to be acceptable as an extraction method for the polymer systems mainly due to a low salvation efficiency of the organic solvents. Soxhlet, accelerated solvent and microwave extraction methods exhibited over 80% of extraction efficiency for toluene. The supercritical fluid extraction method, which has been used as an extraction method for flame retardants in polymers, showed the extraction efficiencies of ca. 100% for PC and PP in the optimal extraction conditions of $60^{\circ}C$ and 120 bar.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.8
• /
• pp.564-570
• /
• 2013

Domestic treatment facilities for acid mine drainage (AMD) mostly used a passive treatment process. But some passive treatment facility discharged high manganese concentrations because it is required high pH (>9) for abiotic oxidation of Mn(II) to Mn(IV). This study was focused on the feasibility of biological manganese treatment using the manganese-oxidizing bacteria (Pseudomonas sp. MN5) from AMD and economical application method of it. To investigate the various conditions of water quality the most part of the experiments were based on batch test. And result of it showed that maximum manganese oxidation rate were $10.4mg/L{\cdot}h$ at the pH7. We also performed small column tests in which MOB were attached to the functional polyurethane (FPU) media containing alkaline chemicals. Manganese concentration decreased 42 mg/L to below 6 mg/L. But anaerobic condition formed by excessive bacterial respiration in column resulted in increasing effluent manganese concentration.

• Economic and Environmental Geology
• /
• v.35 no.3
• /
• pp.285-297
• /
• 2002

This study was carried out to prove the factor properties of the soil affected by a forest fire through the physical and chemical analysis and the data from the conclusion of those analysis are applied to the development of technics that reduces a forest fire-induced 2nd damage. The forest fire was in December 2000 at Gangreung city and Donghae city, Gangwon provinces, Korea. Soil samples were collected at upper layers (0-5 cm) and bottom layers (5-40 cm) in November 2001 from the burned and control sites. Values of pH in burned soils of the upper layers affected by forest fire are higher than those in control soils. Both the fragments of fire-burned plant and differences of geological properties are resulted in a class of soil. Contents of organic matters in burned soils are higher than those in control soils, exceptionally the contents of organic matters in burned soils that contain coaly shale are lower than those in control soils. Weathering indices in burned soils are higher than those in control soils and it concerned with loss of soil. Iron ions Fe(Fe$^{2+}$ or Fe$^{3+}$) are easily extracted from the burned soils by rainfall, but Mn ions are straightly exist in the burned soils by physiochemical adsorption of colloid. Through the sequential extraction in the burned soils and control soils, we are certificate the extraction of Fe ions and the disturbance of Mn ions from the burned soils. As a consequence of factor analysis in burned soil and control soil, we are certificate that the influence of forest fire results in a disturbance of positive correlation factors.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.4
• /
• pp.472-476
• /
• 2008

The possibility of DNA comet assay as a rapid method for screening the irradiated vegetables and grains was evaluated. Vegetables (spring onion, garlic, and tomato) irradiated at $0{\sim}3$ kGy and grains (rice flour and black soybean) irradiated at $0{\sim}9$ kGy were used as samples. Optimum DNA comet assay conditions, such as elution, sedimentation of suspension, and lysis time of cell, were established. The optimum conditions for vegetables were 10 min for the elution time, 0 min for the sedimentation time, and 5 min for the lysis time. The optimum conditions for grains were 15 min for the elution time, 60 min for the sedimentation time, and 30 min for the lysis time. For the food application of DNA comet assay, it was possible to screen various food samples irradiated at the following doses: spring onion at 2 kGy, garlic at 3 kGy, tomato at 1 kGy, rice flour at 9 kGy, and black soybean at 3 kGy. Each sample showed different forms and sizes in DNA comet. Therefore, further studies on various methods using comet shape, concentration, or area in DNA comet assay are necessary.