• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.33-37
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• 1990

A simple and rapid method, based on separation of a flying oil into monomeric, dimeric and oligomeric triglyceride by means of high performance size exclusion chromatography on Ultrastyragel column (500 A), is proposed for evaluation of the quality of used frying oil. The relative area of the monomeric triglyceride was decreased with frying time increase, however, the decrease rate was significantly reduced by treatment of a composited powder (porous rhyorite/citric acid 40/56/4). This measurement showed good linear relationship with change in polar component measurement. There were no significant differences between the slopes of regression lines in both treated and non-treated frying oil system for relationship between monomeric triglyceride and polar component. By this method, it was found that a frying oil habe to be discarded if the content monomeric triglyceride decreased to 71%, which was corresponed to 27% polar component.

• Macromolecular Research
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• v.14 no.3
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• pp.383-386
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• 2006

High temperature size exclusion chromatography (SEC) has been used widely for the characterization of crystalline polymers, for which high temperature operation above the polymer melting temperature is required to dissolve the polymers. However, this high temperature operation has many advantages in SEC separation in addition to merely increasing polymer solubility. At high temperature the eluent viscosity decreases, which in turn decreases the column backpressure and increases the diffusivity of the analytes. Therefore, many reports on the high temperature operation of high performance liquid chromatography (HPLC) have focused on shortening the analysis time and enhancing the resolution. However, the application of high temperature SEC analysis to exploit the merits of high temperature operation is scarce. In this article, therefore, we report on a new apparatus design for high temperature SEC.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.682-689
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• 2008

The purpose of this study was to find out the variation between molecular size distribution (MSD) of natural organic matter (NOM) in raw waters after different water treatment processes like conventional process (coagulation, flocculation, filtration) followed by advanced oxidation process (ozonation, GAC adsorption). The MSD of NOM of Suji pilot plant were determined by Liquid Chromatography-Organic Carbon Detection (LC-OCD) which is a kine of high-performance size-exclusion chromatography (HPSEC) with nondispersive infrared (NDIR) detector and $UV_{254}$ detector. Five distinct fractions were generally separated from water samples with the Toyopearl HW-50S column, using 28 mmol phosphate buffer at pH 6.58 as an eluent. Large and intermediate humic fractions were the most dominant fractions in surface water. High molecular weight (HMW) matter was clearly easier to remove in coagulation and clarification than low molecular weight (LMW) matter. Water treatment processes removed the two largest fractions almost completely shifting the MSD towards smaller molecular size in DW. No more distinct variation of MSD was observed by ozone process after sand filtration but the SUVA value were obviously reduced during increase of the ozone doses. UVD results and HS-Diagram demonstrate that ozone induce not the variation of molecular size of humic substance but change the bond structure from aromatic rings or double bonds to single bond. Granular activated carbon (GAC) filtration removed 8~9% of organic compounds and showed better adsorption property for small MSD than large one.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.446-450
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• 1996

To investigate the effect of heating conditions on the polymerization of methyl linoleate, the esters were heated at $60^{\circ}C,\;90^{\circ}C,\;120^{\circ}C$ and $150^{\circ}C$, respectively, with sparging oxygen for different periods of time. On the basis of the peroxide curve obtained at each of the four temperatures, four heating times were chosen for the analysis of the polymers and total oxidation products. Significant linear relationships were found between polymer contents and total oxidation product contents. The contents of polymers and their linkage types were analyzed by High Performance Size Exclusion Chromatography. The polymers formed at four temperatures were qualitatively identified as dimers. The dimers with peroxide linkages were detected from methyl linoleate oxidized at $60^{\circ}C\;and\;90^{\circ}C$ but they were not detected from methyl linoleate oxidized at $120^{\circ}C\;and\;150^{\circ}C$. Therefore, all dimers formed at $120^{\circ}C\;and\;150^{\circ}C$ seemed to be the ones with ether linkage or carbon to carbon linkage. The degradation rate of the dimers with peroxide linkages at $90^{\circ}C$ was faster than at $60^{\circ}C$.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.270-274
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• 2007

To characterize the polysaccharides which exist as soluble forms in fruit wines, crude polysaccharides were isolated from red, white, raspberry, wild grape, and pear wine, respectively. Among them, the crude polysaccharide (RW-0) in red wine showed the highest yield and considerable amounts of thiobarbituric acid (TBA)-positive materials. The pectic polysaccharide RW-2 was purified to homogeneity from RW-0 by subsequent size-exclusion chromatography using Sephadex G-75 and its structure was characterized. RW-2 consisted of 14 different monosaccharides which included rarely observed sugars in general polysaccharides, such as 2-O-methyl-fucose, 2-O-methyl-xylose, apiose (Api), 3-C-carboxy-5-deoxy-L-xylose (aceric acid, AceA), 3-deoxy-D-manno-2-octulosonic acid (Kdo), and 3-deoxy-D-lyxo-2-heptulosaric acid (Dha). Methylation analysis indicated that RW-2 comprised at least 20 different glycosyl linkages such as 3,4-linked fucose, 2,3,4-linked rhamnose, 3'-linked apiose, and 2,3,3'-linked apiose, being characteristic in rhamnogalacturonan II (RG-II). High performance size-exclusion chromatography indicated that RW-2 mainly comprised RG-II of higher molecular weight (12,000), and that the changes of molecular weight to apparent 7,000 under less than pH 2.0 were observed. These analyses indicated that the higher molecular weight polysaccharide in RW-2 was mainly present as a RG-II dimer.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.16 no.1
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• pp.9-18
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• 2010

For screening test of the non-volatile compounds which migrate from food packaging materials into foodstuffs, the traditional high performance liquid chromatography (HPLC) systems suffer from the lack of universal detector with high sensitivity and universality and high efficiency HPLC separation column which provides complete separation of complex mixtures into all individual substances. In this work, the use possibility of online two-dimensional liquid chromatography (2D-LC) system coupled with a charged aerosol detector (CAD), a universal detector, was reviewed. 2D-LC system permits to improve peak capacity and resolving power for complex mixtures. Charged aerosol detector (CAD) offers a new feasibility for detection of any non-volatile compounds with high sensitivity and constant response factor in a calibration range. The combination of size exclusion chromatography (SEC) and normal phase HPLC (NP-HPLC) is most frequently used for the separation of the natural and synthetic polymers which are mainly used as raw materials for the manufacture of food packaging materials. However, there is no commercial software available for data acquisition and handling and therefore the quantification in 2D-LC analysis is still rare.

• Archives of Pharmacal Research
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• v.21 no.3
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• pp.291-297
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• 1998

Cop protein has been overexpressed in Escherichia coli using a T7 RNA polymerase system. Purification to apparent homogeneity was achieved by the sequential chromatography on ion exchange, affinity chromatography, and reverse phase high performance liquid chromatography system. The molecular weight of the purified Cop was estimated as 6.1 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). But the molecular mass of the native state Cop was shown to be 19 kDa by an analytical high performance size exclusion chromatography, suggesting a trimer-like structure in 50 mM Tris-HCI buffer (pH 7.5) containing 100 mM NaCl. Cop protein Was calculated to contain $39.1% {\alpha}-helix, 16.8% {\beta}-sheet$, 17.4% turn, and 26.8% random structure. The DNA binding property of Cop protein expressed in E. coli Was preserved during the expression and purification process. The isoelectric point of Cop was determined to be 9.0. The results of amino acid composition analysis and N-terminal amino acid sequencing of Cop showed that it has the same amino acid composition and N-terminal amino acid sequence as those deduced from its DNA sequence analysis, except for the partial removal of N-terminal methionine residue by methionyl-aminopeptidase in E. coli.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2663-2670
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• 2013

The purpose of stability testing is to provide evidence about how the quality of a drug varies with time under the influence of a variety of environmental factors. In this study, erythropoietin (EPO) was analyzed under different pH (pH 3 and pH 9) and temperature ($25^{\circ}C$ and $40^{\circ}C$) conditions according to current Good Manufacturing Practice (cGMP) and International Conference on Harmonisation (ICH) guidelines. The molecular weight difference between intact EPO and deglycosylated EPO was determined by SDS-PAGE, and aggregated forms of EPO under thermal stress and high-pH conditions were investigated by size exclusion chromatography. High pH and high temperature induced increases in dimer and high molecular weight aggregate forms of EPO. UPLC-ESI-TOF-MS was applied to analyze the changed modification sites on EPO. Further, normal-phase high-performance liquid chromatography was performed to identify proposed glycan structures and high pH anion exchange chromatography was carried out to investigate any change in carbohydrate composition. The results demonstrated that there were no changes in modification sites or the glycan structure under severe conditions; however, the number of dimers and aggregates increased at $40^{\circ}C$ and pH 9, respectively.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.872-877
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• 2009

By-products of marine organisms including salmon, skate, flatfish, and yellow goosefish were investigated to search for new source of chondroitin sulfate (CS). Agarose gel electrophoresis with chondroitinase depolymerization showed that purified chondroitin sulfate did not contain any other glycosaminoglycans. 1H-nuclear magnetic resonance (NMR) spectra were acquired to confirm the structure and purity. The average molecular weight ranging from 22 to 64 kDa was determined by high performance size exclusion chromatography. Disaccharide compositions and purities were determined by strong anion exchange-high performance liquid chromatography (SAX-HPLC) after chondroitinase ABC depolymerization. SAX-HPLC data exhibited that the purity was from $81.7{\pm}1.3$ to $114.2{\pm}2.5%$ and the yield was from 1.3 to 12.5%. All analytical results indicate that salmon cartilage, skate cartilage, and yellow goosefish bone could be promising sources of CS to substitute shark cartilage CS in commercial neutraceuticals.

• Mycobiology
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• v.41 no.3
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• pp.149-154
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• 2013

An ${\alpha}$-glucosidase inhibitor was developed from Aspergillus oryzae N159-1, which was screened from traditional fermented Korean foods. The intracellular concentration of the inhibitor reached its highest level when the fungus was cultured in tryptic soy broth medium at $27^{\circ}C$ for five days. The inhibitor was purified using a series of purification steps involving ultrafiltration, Sephadex G-25 gel permeation chromatography, strong cation exchange solid phase extraction, reverse-phase high performance liquid chromatography, and size exclusion chromatography. The final yield of the purification was 1.9%. Results of the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis indicated that the purified ${\alpha}$-glucosidase inhibitor was a tri-peptide, Pro-Phe-Pro, with the molecular weight of 360.1 Da. The IC50 value of the peptide against ${\alpha}$-glucosidase activity was 3.1 mg/mL. Using Lineweaver-Burk plot analysis, the inhibition pattern indicated that the inhibitor acts as a mixed type inhibitor.