• Journal of Food Hygiene and Safety
• /
• v.8 no.4
• /
• pp.251-254
• /
• 1993

Extraction and Clean-up procedures coupled with quantitation by high performance liquid chromatography(HPLC) was evaluated for the detection of 4 aflatoxins, B1, B2, G1 and G2, in peanut butter. The Sep-pak clean-up method showed poorer separation and repeatability than did the modified DeVries' and an immunoaffinity column clean-up methods. No significant difference of detected aflatoxins between the affinity column clean-up and modified DeVries' method. The coefficients of variation for the 4 aflatoxins were ranging from 6.3∼32.3 by the modified DeVries' method and 5.3∼9.8 by the affinity column clean-up.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.23 no.3
• /
• pp.459-465
• /
• 1994

Performance of a continuous cocurrent supercritical fluid extraction column for processing of anhydrous milk fat (AMF) was determined. The extract loading increased and the extraction yield decreased as the superficial velocity of AMF increased. The maximum solubility of AMF in $CO_2$ at 4$0^{\circ}C$/3,500 psig was 0.0195g/g. The increase of the carbon dioxide density enhanced the solubility of milk fat and decreased the cholesterol concentration in the extract. Three operation conditions, such as recycle , reflux, and temperature gradient of extraction column, were tested. More short-chain fatty acvids were extracted by the reflux operation . Longchain fatty acids and thehighest ratio fo long-chain unsaturated to saturated fatty acids were also obtained in the raffinate phase with refluex.

• Journal of Ginseng Research
• /
• v.13 no.2
• /
• pp.254-259
• /
• 1989

A radioprotective ginseng protein fraction was obtained from Korean white ginseng powder by the following isolation and purification procedures: Tris-HCI buffer extraction, 70% ammonium sulfate fractionation, CM-rellulosr column chromatography, heat inactivation and Sephadex G-75 column chromatography. This fraction was further purified by Sepharose 4B and Sephadex G-150 column chromatographies. Three fractions obtained were subjected to Native-PAGE and SDS-PAGE using gradient gels and the silver staining method. Molecular weights of the native proteins and their subunits were estimated.

• Journal of Ocean Engineering and Technology
• /
• v.35 no.4
• /
• pp.296-304
• /
• 2021

Research on the development of marine renewable energy is actively in progress. Various studies are being conducted on the development of wave energy converters. In this study, a numerical analysis of wave-energy extraction performance was performed according to the body shape and scale of the sloped oscillating water column (OWC) wave energy converter (WEC), which can be connected with the breakwater. The sloped OWC WEC was modeled in the time domain using a two-dimensional fully nonlinear numerical wave tank. The nonlinear free surface condition in the chamber was derived to represent the pneumatic pressure owing to the wave column motion and viscous energy loss at the chamber entrance. The free surface elevations in the sloped chamber were calculated at various incident wave periods. For verification, the results were compared with the 1:20 scaled model test. The maximum wave energy extraction was estimated with a pneumatic damping coefficient. To calculate the energy extraction of the actual size WEC, OWC models approximately 20 times larger than the scale model were calculated, and the viscous damping coefficient according to each size was predicted and applied. It was verified that the energy, owing to the airflow in the chamber, increased as the incident wave period increased, and the maximum efficiency of energy extraction was approximately 40% of the incident wave energy. Under the given incident wave conditions, the maximum extractable wave power at a chamber length of 5 m and a skirt draft of 2 m was approximately 4.59 kW/m.

• Journal of Korean Society on Water Environment
• /
• v.22 no.5
• /
• pp.879-886
• /
• 2006

The analytical methods of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) for water sample with extremely low concentration was developed to extract large volume and to improve fast chromatography for clean up. Semi-automated solid phase extraction (SPE) system and column coupling chromatography using elution pump was optimized and applied to each processes of treatment plant. Results of disk type SPE indicated that this system was applicable below 40 L of aqueous sample with a flow rate of 0.08 ~ 0.2 L/min. Average recoveries of SPE using labeled sampling spike of $^{37}Cl$-2,3,7,8-TCDD was 97%. Column coupling method resulted in reduced clean up time, solvent volume, increased average recoveries with constant elution rate. The combined methods were applied to the monitoring of drinking water treatment plant. Limits of detection (LOD) of each process were calculated. For example, LOD of raw and treated water ranged 0.094~0.968 pg/L and 0.028~0.364 pg/L, respectively. Combined methods of extraction and cleanup techniques provided fast analysis of PCDD/Fs with high accuracy and low LODs for water samples.

• Economic and Environmental Geology
• /
• v.35 no.3
• /
• pp.221-227
• /
• 2002

Column experiments were performed to evaluate the removal efficiency of soil vapor extraction (SVE) iota TCE (trichloroethylene) and toluene in soil. Homogeneous Ottawa sands and real soils collected from contaminated area were used to investigate the effect of soil properties and SVE operation conditions on the removal efficiency. In column teats with two different sizes of Ottawa sand, the maximum effluent TCE concentration in a coarse sand column was 442 mg/L and 337 mg/L in a fine sand column. However, after 20 liter gas flushing, the effluent concentrations were very similar and more than 90% of initial TCE mass were removed from the column. For two real contaminated soil columns, the maximum effluent concentration decreased 50% compared with that in the homogeneous Ottawa coarse sand column, but 99% of initial TCE mass were extracted from the column within 40 liter air flushing, suggesting that SVE is very available to remove volatile NAPLs in the contaminated soil. To investigate the effect of contaminant existing time on the removal efficiency, an Ottawa sand column was left stable for one week after TCE was injected and the gas extraction was applied into the column. Its effluent concentration trend was very similar to those for other Ottawa sand columns except that the residual TCE after the air flushing showed relatively high. Column tests with different water contents were performed and results showed high removal efficiency even in a high water content sand column. Toluene as one of BTEX compounds was used in an Ottawa sand column and a real soil column. Removal trends were similar to those in TCE contaminated columns and more than 98% of initial toluene mass were removed with SVE in both column.

• Korean Journal of Veterinary Service
• /
• v.29 no.3
• /
• pp.339-346
• /
• 2006

Semi-micro-HPLC using a column-switching technique was developed for simultaneous determination of vitamin A and E contents in infant formula. Vitamin A and E were extracted by PDA - HPLC with reversed phase column using organic solvent and their contents in Certified Reference Material (CRM) and infant formula were determined and compared with hydrolysis method and rapid extraction. Developed method has many advantages of simple and rapid sample preparation and simultaneous determination of vitamin A and E by micro-HPLC using reversed phase column.

• Analytical Science and Technology
• /
• v.31 no.3
• /
• pp.112-121
• /
• 2018

The hydrothermal carbonization method has received great attention because of the conversion process from biomass. The reaction produces various products in hydrochar, bio-liquid, and gas. Even though its yield cannot be ignored in amount, it is difficult to find research papers on bio-liquid generated from the hydrothermal carbonization reaction of biomass. In particular, the heterogeneity of feedstock composition may make the characterization of bio-liquid different and difficult. In this study, bio-liquid from the hydrothermal carbonization reaction of food wastes at $230^{\circ}C$ for 4 h was investigated. Among various products, fatty acid methyl esters were analyzed using two different extraction methods: liquid-liquid extraction and column chromatography. Different elutions with various solvents enabled us to categorize the various components. The eluents and fractions obtained from two different extraction methods were analyzed by gas chromatography with a mass spectrometer (GC/MS). The composition of the bio-liquid in each fraction was characterized, and seven fatty acid methyl esters were identified using the library installed in GC/MS device.

• Journal of Ginseng Research
• /
• v.22 no.3
• /
• pp.155-160
• /
• 1998

This stuffy was carried to establish a new efficient method for the preparation of edible crude ginseng saponin. The conventional butanol extraction and resin adsorption methods were compared for the contents of total crude ginseng saponin and major ginsenosides. Seventy- percent methanol extract was applied to Diaion HP-20 column and the resin was washed with Hn and eluted with absolute methanol. The methanol elute was dried in vivo and analyzed for its ginsenosides. Use of ethanol instead of methanol to make edible crude ginseng saponin gave a similar result. Butanol extraction was performed by the conventional method. The final aqueous layer from butanol extraction was passed through Diaion HP-20 column followed by elution with methanol and Diaion HP-20 passed fraction was extracted with butanol to recover remaining components, respectively, in order to determine saponin loss. TLC and HPLC qualitatively and quantitatively monitored Ginsenosides, respectively. Loss of ginsenosides was higher in butanol extraction method than in Diction HP-20 adsorption method. In addition, saponin fractions prepared by Diction HP-20 adsorption method showed higher content of each ginsenoside, showing 8.2% higher purity than that of butanol extracted fraction. From these results, we propose the resin adsorption method as a new efficient measure for the preparation of crude ginseng saponin, which is edible by using spirit instead of methanol.

• Nuclear Engineering and Technology
• /
• v.32 no.4
• /
• pp.309-315
• /
• 2000

The changes of Np oxidation state in nitric acid and the effect of nitrous acid on the oxidation state were analyzed by spectrophotometry, solvent extraction, and electrochemical methods. An enhancement of Np extraction to 30 vol.% TBP was carried out through adjustment of Np oxidation state by using a glassy carbon fiber column electrode system. The information of electrolytic behavior of nitric acid was important because the nitrous acid affecting the Np redox reaction was generated during the electrolytic adjustment of the Np oxidation state. The Np solution used in this work consisted of Np（V) and Np（Ⅵ）without （IV）. The composition of Np（V) in the range of 0.5M -5.5 M nitric acid was 32% ~ 19%. The electrolytic oxidation of Np（V) to Np（Ⅵ）in the solution enhanced Np extraction efficiency about five times higher than the case without the electrolytic oxidation. It was confirmed that the nitrous acid of less than about 10-5 M acted as a catalyst to accelerate the chemical oxidation reaction of Np（V) to Np（Ⅵ）.