• Title/Summary/Keyword: reversed phase

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The Effect of Water Content on Hen Egg lysozyme Extraction using Reversed Micelles and Pressurized Carbon Dioxide (가압 이산화탄소와 역미셀을 이용한 난백 lysozyme의 추출에 대한 수분함량의 영향)

  • 박선영;전병수
    • KSBB Journal
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    • v.18 no.3
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    • pp.202-206
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    • 2003
  • A study of hen egg lysozyme extraction using reversed micelles and pressurized CO₂ phase was conducted. The relationship between the lysozyme extraction and water content (W/sub 0/) under the pressurized CO₂ conditions was investigated. The water content of the micellar organic phase was a significant parameter affecting the mass transfer of protein and enzymatic activity in reversed micellar process. It was found that the reversed micelles in the organic phase with pressurized CO₂ were larger than the organic phase without CO₂. Therefore, the extractionrate of lysozyme in the interface of the aqueous phase and the organic phase was increased. W/sub 0/ value was increased at the high surfactant concentration and the extraction rate of lysozyme was enhanced.

Effect of Retained and Reversed Austenite on the Damping Capacity in High Manganese Stainless Steel (고 Mn 스테인리스강의 감쇠능에 미치는 잔류 및 역변태 오스테나이트의 영향)

  • Kim, Y.H.;Lee, S.H.;Kim, S.G.;Kang, C.Y.
    • Korean Journal of Materials Research
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    • v.25 no.1
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    • pp.9-15
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    • 2015
  • The effect of retained and reversed austenite on the damping capacity in high manganese stainless steel with two phases of martensite and austenite was studied. The two phase structure of martensite and retained austenite was obtained by deformation for various degrees of deformation, and a two phase structure of martensite and reverse austenite was obtained by reverse annealing treatment for various temperatures after 70 % cold rolling. With the increase in the degree of deformation, the retained austenite and damping capacity rapidly decreased, with an increase in the reverse annealing temperature, the reversed austenite and damping capacity rapidly increased. With the volume fraction of the retained and reverse austenite, the damping capacity increased rapidly. At same volume of retained and reversed austenite, the damping capacity of the reversed austenite was higher than the retained austenite. Thus, the damping capacity was affected greatly by the reversed austenite.

The Rapid Determination of Gemcitabine by Reversed-phase Ultra-Performance Liquid Chromatography (역상 초고속액체크로마토그라피에 의한 gemcitabine의 빠른 농도 분석법)

  • Park, Dae-Jin;Kim, Woo-Mi
    • Journal of Life Science
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    • v.19 no.12
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    • pp.1698-1704
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    • 2009
  • Gemcitabine is an anticancer drug used to treat a variety of solid tumors. The drug is rapidly inactivated by cytidine deaminase in plasma and its hydrophilicity restricts the extent of quantification that is possible using reversed-phase liquid chromatography. In this paper, we report a rapid and precise method to analyze velocity and peak efficiency using ultra-performance liquid chromatography (UPLC) with a reversed-phase column. The retention periods of gemcitabine and 2'-deoxycytidine at 283 nm were 3.2 and 2.1 min, respectively. The assay provided highly linear results in the range of $0.1{\sim}20{\mu}g/ml$ ($r^2$ > 0.999). The coefficients of variation of the intra-day and inter-day assays were less than 10.0%. We observed that the estimated average concentrations of the intra-day and inter-day assays ranged from 97.3 to 113.5% to verify the accuracy. These results suggest that this new reversed-phase UPLC method is a rapid and reliable way of determining gemcitabine levels.

Enantiomer separation using a covalently immobilized chiral column derived from polysaccharide derivative by reversed phase liquid chromatography (역상 크로마토그래피에서 다당유도체로 공유결합된 키랄 컬럼을 이용한 거울상 이성질체의 광학분리)

  • Huang, Hu;Jin, Jing Yu;Baek, Chae-Sun;Lee, Wonjae
    • Analytical Science and Technology
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    • v.22 no.2
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    • pp.148-151
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    • 2009
  • Enantiomer separation of N-fluorenylmethoxycarbonyl (FMOC) $\alpha$-amino acid was performed on covalently immobilized chiral column (Chiralpak IB) based on polysaccharide derivative as a chiral selector by reversed phase liquid chromatography. The effect of the reversed mobile phase on the chromatographic parameters of the enantioselectivities, resolution factors and retention times using covalently immobilized Chiralpak IB was shown. Also the enantiomer separation of N-FMOC $\alpha$-amino acid in the reversed and normal phase was compared and the results obtained in the former mobile phase were generally lower than those in the latter mobile phase.

Effect of Reversed Austenite on the Damping Capacity of Austenitic Stainless Steel (오스테나이트계 스테인리스강의 감쇠능에 미치는 역변태 오스테나이트의 영향)

  • Kim, Young-Hwa;Sung, Ji-Hyun;Kang, Chang-Yong
    • Journal of Power System Engineering
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    • v.19 no.1
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    • pp.70-75
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    • 2015
  • The influence of reversed austenite on the damping capacity in austenitic stainless steel with two phase of martensite and reversed austenite was investigated. The two phases of deformation induced martensite and reversed austenite was obtained by an reverse annealing treatment at $500^{\circ}C{\sim}700^{\circ}C$ for various time after 70% cold rolling. With an increase of the reverse annealing treatment temperature and time, volume fraction of reversed austenite was rapidly increased. With an increase of volume fraction of reveresd austenite, damping capacity was rapidly increased. At same volume of reveresd austenite, damping capacity of reversed austenite obtained by reverse annealing treatment at $700^{\circ}C$ for various time was higher then reveresd austenite obtained by reverse annealing treatment at $500^{\circ}C{\sim}700^{\circ}C$ for 10min. Thus, the damping capacity was affected greatly by reversed austenite obtained by annealing treatment at $700^{\circ}C$ for various time.

Enantiomeric Separation of Free Amino Acids Using N-alkyl-L-proline Copper(Ⅱ) Complex as Chiral Mobile Phase Additive in Reversed Phase Liquid Chromatography

  • Lee Sun Haing;Oh Tae Sub;Lee Hae Woon
    • Bulletin of the Korean Chemical Society
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    • v.13 no.3
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    • pp.280-285
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    • 1992
  • Enantiomeric separation of free amino acids has been achieved by a reversed phase liquid chromatography with addition of a Cu(Ⅱ) complex of N-alkyl-L-proline (alkyl: propyl, pentyl or octyl) to the mobile phase. The amino acids eluted were detected by a postcolumn OPA system. N-alkyl-L-proline was prepared and used as a chiral ligand of Cu(Ⅱ) chelate for the enantiomeric separation. The concentration of the Cu(Ⅱ) chelate, the organic modifier and pH affect the enantiomeric separation of free amino acids. The retention behaviour, varied with change in pH and the concentration of the Cu(Ⅱ) chelate, was different compared with those of the derivatized amino acids. The elution orders between D- and L-forms were consistent except histidine showing that L-forms elute earlier than D-forms. The retention mechanism for the enantiomeric separation can be illustrated by the stereospecificity of the ligand exchange reaction and the hydrophobic interaction between the substituent of amino acids and reversed phase, $C_18$.

Relationship Between Mechanical Properties and Damping Capacity in Stainless Steel with Two Phases of Reversed Austenite and Deformation Induced Martensite (역변태 오스테나이트와 가공유기 마르텐사이트의 2상 혼합조직을 갖는 스테인리스강의 기계적 성질과 감쇠능)

  • Namgung, Won;Jung, Mok-Hwan;Lee, Hyang-Beak;Kim, Jae-Nam;Kang, Chang-Young
    • Journal of Power System Engineering
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    • v.17 no.2
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    • pp.114-120
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    • 2013
  • This study was carried out to investigate the relationship between mechanical properties and damping capacity in high manganese austenitic stainless steel with two phase mixed structure of reversed austenite and deformation induced martensite. Reversed austenite of ultra-fine grain size less than $0.3{\mu}m$ was obtained by reversion treatment. Two phase structure of deformation induced martensite and reversed austenite was obtained by annealing treatment at range of $500^{\circ}C{\sim}700^{\circ}C$ for various time in cold rolled high manganese austenite stainless steel. In stainless steel with two phase mixed structure of martensite and austenite, damping capacity decreased rapidly with the increasing hardness and strength. With the increasing elongation, damping capacity was increased rapidly and then, slowly increased.

Determination of Fluorescent Whitening Agents in Paper Materials by Ion-Pair Reversed-Phase High-Performance Liquid Chromatography

  • Kim, Jeong Soo;Kim, Do Hwan;Kim, Keon
    • Bulletin of the Korean Chemical Society
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    • v.33 no.12
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    • pp.3971-3976
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    • 2012
  • A simple method was developed for the analysis of seven stilbene-type fluorescent whitening agents (FWAs) in paper materials by ion-pair reversed-phase high-performance liquid chromatography with fluorescence detection. These stilbene-type FWAs included two disulfonate, two tetrasulfonate, and three hexasulfonate compounds. After optimization of chromatographic conditions, the FWAs were satisfactorily separated using a reversed-phase column (RP-18) with the following isocratic mobile phase: methanol-water (60:40) containing 17.5 mM TBABr and 10 mM citrate buffer (pH = 7.0). The calibration plot was linear in the range from 5 to 500 ng/mL for two disulfo-FWAs and from 1 to 500 ng/mL for the other five FWAs. Precision levels of the calibration curve as indicated by RSD of response factors were 1.2 and 8.1%. Limits of quantitation (LOQ) ranged from 1.2 to 11 ng/mL.

Separation of Burnup Monitors in Spent Nuclear Fuel Samples by Liquid Chromatography

  • Joe, Kih-Soo;Jeon, Young-Shin;Kim, Jung-Suck;Han, Sun-Ho;Kim, Jong-Gu;Kim, Won-Ho
    • Bulletin of the Korean Chemical Society
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    • v.26 no.4
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    • pp.569-574
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    • 2005
  • A coupled column liquid chromatography system was applied for the separation of the burnup monitors in spent nuclear fuel sample solutions. A reversed phase column was studied for the adsorption behavior of uranyl ions using alpha-hydroxyisobutyric acid as an eluent and used for the separation of plutonium and uranium. A cation exchange column prepared by coating 1-eicosylsulfate onto the reversed phase column was used for the separation of the lanthanides. In addition, retention of Np was checked with the reversed phase column and cation exchange column, respectively, according to the oxidation states to observe the interference effect for the separation of burnup monitors. This chromatography system showed a great reduction in separation time compared to a conventional anion exchange method. A good agreement from the burnup data was obtained between for this method and a conventional anion exchange method to within 1% of a difference for the spent nuclear fuel samples of about 40 GWD/MTU.

Extractive Separation of an Alkaline Protease Using Reversed Micelles (역미셀을 이용한 Alkaline Protease의 추출분리)

  • 윤현희
    • KSBB Journal
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    • v.5 no.4
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    • pp.411-414
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    • 1990
  • The extraction behavior of an alkaline protease using reversed micelles was investgated. The reversed micellar solution consisted of AOT in isooctane. It was found that distribution of arkaline protease into the organic phase increased at lower pH, lower ionic strength, and higher AOT concentration. When the real fermentation broth was extracted of alkaline protease, an activity yield of 20% and a purification factor of 2.0 were obtained.

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