• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.21-26
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• 2005

Gas Chromatography (GC) is a wisely technique used for the separation and analysis of liquid and gas sample. Separation of the sample vapors is achieved via their differential migration through a capillary column with an insert carrier gas. The identity and quantity of each vapor in the mixer can be determined from its retention time in the column and a particular property of the gas, such as thermal conductivity, which can be related to the concentration of sample vapor in the carrier gas. Therefore, the flow characteristics in the spiral gas chromatographic column are numerically investigated in this study. Especially, different pressure drop between the front and the rear of GC column with various flow rates is estimated the governing equations are derived from making using of three-dimensional Naver-Stokes equation with incompressible and laminar model due to the nature of low Reynolds number flow. Using a commercial code, FLUENT, the pressure and flow fields in GC column are calculated with various flow rates. The characteristics of thermal cycling which is one of the most important factors affecting the column efficiency and analysis time is also estimated. Furthermore, numerical analyses are also carried out by using commercial code, ANSYS, with various values of power, which is applied to the heating element located at lower GC column.

• Bulletin of the Korean Chemical Society
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• 제22권4호
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• pp.409-412
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• 2001

Poly(p-tert-butyltrimethoxymonopropyloxycalix[4]arene-methylsiloxane) (TBCX-MS) has been prepared and used as a stationary phase in isothermal capillary gas chromatographic separation of some positional isomers. Retention factors (k) and separatio n factors $(\alpha)$ for the isomers were measured and compared with those on poly(p-tert-butyl-dimethoxydipropyloxycalix[4]arene-tetramethyldisiloxane) (TBCX-TMDS), poly(dimethoxydipropyloxycalix[4]arenetetramethyl-disiloxane) (CX-TMDS). Most of the isomers investigated are well resolved on TBCX-MS. Retention of all the compounds decreases on the three phases in the order, TBCX-TMDS ${\geq}$ TBCX-MS > CX-TMDS. Similar retention values on TBCX-TMDS and TBCX-MS seem to indicate that retention property of the two phases is not significantly affected by the spatial position of the calixarene moiety.

• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1775-1779
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• 2006

A liquid chromatographic chiral stationary phase (CSP) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxilic acid without extra free aminopropyl groups on silica surface has been demonstrated to be quite effective for the resolution of various $\beta$-amino acids. The retention factors ($k_1$) for the resolution of $\beta$-amino acids on the CSP were quite large and the large retention factors might be quite attractive along with the reasonable separation factors ($\alpha$) for preparative scale enantioselective chromatography. The large retention factors on the CSP were found to be reduced effectively by adding ammonium ion to mobile phase without sacrificing the chiral recognition efficiency of the CSP. Consequently, the CSP is also quite applicable for use in analytical enantioselective chromatography.

• KSBB Journal
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• 제27권4호
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• pp.232-236
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• 2012

Comparative liquid chromatographic enantiomer separation of ${\alpha}$-amino acids, their esters and primary amino compounds was performed using two chiral stationary phases (CSPs) prepared by covalently bonding (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid (18-C-6-TA) of the same chiral selector. In general, the separation factors and resolution factors for these analytes on CSP 1 were greater than on CSP 2, while these capacity factors on CSP 2 were quite greater than on CSP 1. Except for leucine methyl ester and phenylalanine methyl ester, the elution orders of all analytes including ${\alpha}$-amino ${\alpha}$-alkyl acids and phenylglycine alkyl esters on CSP 1 are identical to those on CSP 2. This study showed that different connecting structures for these two CSPs might influence their ability to resolve the analytes depending on their structures related to the chiral recognition mechanism.

• 공업화학
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• 제7권5호
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• pp.985-991
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• 1996

HETP(Height Equivalent to a Theoretical Plate)는 크로마토그래피 공정에서 관의 효율을 나타내는 정량적 인자이다. 본 연구에서는 시료의 농도와 주입량, 이동상의 유속과 조성이 제조용 액체 크로마토그래피의 HETP에 미치는 영향을 고찰하였다. 시료는 thymidine이고 이동상은 1.5~5.5ml/min의 유속에서 일정용매조성법으로 물과 organic modifier로서 메탄올을 사용하였으며 제조용 크로마토그래피 column은 길이가 500mm, 내경이 9.8mm이다. 시료의 농도와 주입부피 및 유속이 증가함에 따라 HETP는 거의 선형적으로 증가하여 관의 효율이 감소하였다. 시료 주입부피의 영향은 관의 효율에 매우 중요하게 작용하여 동일한 주입량에 대하여 주입부피가 10배로 증가함에 따라 HETP는 약 2배 정도로 커졌다. 이동상의 유속이 증가함에 따라서 HETP는 주로 이동상과 고정상의 물질전달저항에 의해서 증가하였다.

• KSBB Journal
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• 제20권4호
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• pp.260-265
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• 2005

N-CBZ-L-phenylalanine를 주형분자로 하고 MAA와 4-VPY를 기능성 단량체로 하여 분자각인 고분자를 합성하였다. N-CBZ-L-phenylalanine와 MAA, 4-VPY는 수소결합의 영향을 많이 받고 있으며 이온결합과 소수성결합도 작용하고 있다. 혼합성분을 기능성 단량체로 사용함으로 하여 단량체의 성분들 사이에서 상호작용 효과를 나타냈다. 실험결과에 의하면 혼합 성분인 MAA와 4-VPY를 기능성 단량체로 한 분자각인 고분자에서의 체류인자가 단일성분인 MAA를 사용한 고분자에서의 체류인자보다 컸고 컬럼 효율은 낮았지만 분리도는 높았다. 산성인 MAA와 염기성인 4-VPY를 함께 사용함으로써 거울상 이성질체인 N-CBZ-L-phenylalanine과 N-CBZ-D- phenylalanine의 분리도를 증가시킬 수 있었다. 혼합된 성분의 기능성 단량체로하여 제조된 분자각인 고분자를 키랄 물질의 분리를 비롯한 천연물질의 분리에 더 광범위하게 사용될 수 있을 것이다.

• 대한화학회지
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• 제53권2호
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• pp.137-143
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• 2009

공유결합된 다당유도체에서 유도된 카이랄 칼럼인 Chiralpak IC을 사용하여 N-BOC $\alpha$-amino acid와 그들의 ethyl ester 유도체의 액체크로마토그래피 거울상 이성질체의 분리를 수행하였다. 다양 한 이동상에서 공유결합된 카이랄 칼럼인 Chiralpak IC에서 거울상 이성질체가 분리된 실험결과를 나 타내었으며, 광학분할의 선택성과 분리인자가 이동상에 따라 크게 영향을 받았다. 또한 동일한 이동 상에서 분석물질의 녹이는 용매에 따라 거울상 이성질체의 분리에 미치는 영향과 분석용 컬럼에서 거울상 이성질체의 분리의 여러 예를 나타내었다.

• 약학회지
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• 제29권6호
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• pp.375-379
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• 1985

The gas chromatographic behavior of optically active N-(N-benzoyl-L-valyl)-anilide used as stationary phase is described. N-(N-benzoyl-L-valyl)-anilide has been synthesized with good yield under mild condition via Schotten-Bauman process and coated on the Chromosorb W AW (80-100mesh) for the purpose of enantiomer separation. The behavior of this compound as optically active stationary phase for the separation of the enantiomers of N-TFA-D, L-amino acid isopropyl esters has been examined with respect to the correlation between the separation factors and column temperatures. All amino acid enantiomers examined were eluted within one hour and the elution pattern showed retention times increasing in the order of alanine, valine, leucine, threonine, proline and methionine.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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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.

• 약학회지
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• 제30권1호
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• pp.47-50
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• 1986

The enantiomers of five amino acids (alanine, valine, threonine, leucine and phenylalanine) could be separated by gas chromatography with optically active (S)-5-isopropyll-$N^3$-phenyl-2-thiohydantoinic stationary phase, which prepared from L-valine and phenylisothiocyanate. Gas chromatographic separations on methylesterificated and N-trifluoroacetylated amino acids have been conducted in isothermal at several column temperatures (180~190, 200, $210^{\circ}C$). The separation factors were 1.29 (alanine, $190^{\circ}C$), 1.35 (valine, $190^{\circ}C$), 1.33 (threonine, $190^{\circ}C$), 1.17 (leucine, $190^{\circ}C$) and 1.05 (phenylalanine, $190^{\circ}C$) and D-isomers eluted prior to L-isomers in every instance. The result of this experiment shows that this stationary phase can be used for the separation of the other amino acids enantiomers.