• 통합자연과학논문집
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• 제8권2호
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• pp.111-116
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• 2015

Liquid chromatographic enantiomer separation of ${\alpha}$-amino acid esters as nitrobenzoxadiazole (NBD) derivatives was performed using several chiral stationary phases (CSPs) based on polysaccharide derivatives under fluorescence detection. For enantiomer separation by normal HPLC, the non-aqueous derivatization method of ${\alpha}$-amino acid esters for NBD analytes was introduced. Among the six CSPs used in this study, the performance of Chiralpak IA was superior for enantiomer resolution of NBD derivatives of several ${\alpha}$-amino acid methyl esters. Also the convenient analytical method using polysaccharide-derived CSPs developed in this study was applied to determine the optical purity of ${\alpha}$-amino acids esters. It was investigated that the enantiomeric impurity levels of 0.02-1.73% were found after determination of enantiomeric purities of several commercially available L-amino acid methyl esters. It is expected to be quite useful for enantiomer separation of other ${\alpha}$-amino acid esters as NBD derivatives by normal HPLC.

• KSBB Journal
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• 제28권6호
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• pp.423-427
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• 2013

A new convenient derivatization method of ${\alpha}$-amino acid esters as nitrobenzoxadiazole (NBD) derivatives for chiral resolution was introduced and the enantiomer separation of ${\alpha}$-amino acid esters as NBD derivatives was performed by normal HPLC using chiral columns based on polysaccharide derivatives. The NBD derivatives were readily prepared by stirring NBD-Cl and ${\alpha}$-amino acid methyl ester HCl with $NaHCO_3$ in ethanol. The performance of Chiralpak IA was superior to the other chiral stationary phases for enantiomer resolution of NBD derivatives of several ${\alpha}$-amino acid methyl esters. Owing to fluorescence detection as well as strong UV absorption, it is expected that the convenient analytical method developed in this study will be very useful for enantiomer separation of ${\alpha}$-amino acid esters as NBD derivatives on polysaccharide-derived chiral columns.

• KSBB Journal
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• 제30권4호
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• pp.197-201
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• 2015

Liquid chromatographic enantiomer separation of ${\alpha}$-amino acids and their methyl and ethyl esters as fluorenylmethoxycarbonyl (FMOC) derivatives was performed using a recently developed chiral column (Chiralpak IE) based on polysaccharide derivative under simultaneous UV detection and fluorescence detection. The degree of enantiomer separation of ${\alpha}$-amino acid esters as FMOC derivatives is generally higher than that of the corresponding ${\alpha}$-amino acids. Especially, ${\alpha}$-amino acid methyl esters showed the greatest enantioseparation. As this method developed in this study can be applied to determine the chemical and optical purity of ${\alpha}$-amino acids and esters, it is expected to be quite useful for their chiral separation using Chiralpak IE.

• KSBB Journal
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• 제26권2호
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• pp.139-142
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• 2011

The chromatographic enantiomer separation of 9-anthraldimine derivatives of ${\alpha}$-amino acid methyl and ethyl esters on four polysaccharide based chiral columns was performed. The 9-anthraldehyde Schiff base derivatives of ${\alpha}$- amino acid esters were readily synthesized by stirring the ${\alpha}$- amino acid ester hydrochloride salts with 9-anthraldehyde in the presence of 1,8-diazabicyclo [5.4.0]undec-7-ene as a base and anhydrous $MgSO_4$. Chiralcel OD or Chiralcel OD-H showed the greatest enantiomer resolution of 9-anthraldimine derivatives of ${\alpha}$-amino acid methyl and ethyl esters. The L-enantiomers of all the analytes were preferentially retained on Chiralcel OD or Chiralcel OD-H. This analytical method was applied in the determination of optical purities of several commercially available D- or L-${\alpha}$-amino acid methyl esters.

• 분석과학
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• 제22권2호
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• pp.148-151
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• 2009

역상 액체 크로마토그래피에서 다당유도체 선택자가 공유결합된 키랄 컬럼인 Chiralpak IB을 사용하여 N-FMOC $\alpha$-amino acid의 광학 이성질체의 분리를 수행하였다. 공유결합된 키랄 컬럼인 Chiralpak IB에서 여러 역상 이동상 조건들이 광학분할의 선택성과 분리인자, 머무름시간에 미치는 영향을 보여주었다. 또한 역상 액체 크로마토그래피에서 N-FMOC $\alpha$-amino acid의 광학 이성질체의 분리 결과를 순상 액체 크로마토그래피 결과와 비교하였는데 순상이동상을 사용한 것보다는 대체적으로 낮은 광학분할을 보여주었다.

• KSBB Journal
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• 제27권3호
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• pp.167-171
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• 2012

A convenient liquid chromatographic enantiomer separation of several ${\alpha}$-amino acid esters as benzophenone Schiff base derivatives on covalently immobilized chiral stationary phases (CSPs) derived from polysaccharide derivatives was developed. The benzophenone imine derivatives of ${\alpha}$-amino acid esters were readily prepared by stirring benzophenone imine and the ${\alpha}$-amino acid ester hydrochloride salts in 2-propanol. The chromatographic conditions used on all CSPs were 0.5% or 5% 2-propanol/hexane (V/V) as the mobile phases at 1 mL/min of flow rate and UV 254 nm detection. The performance of Chiralpak IC among all CSPs was superior to that of the other CSPs for resolution of benzophenone imine derivatives of ${\alpha}$-amino acid esters. It is expected that the developed analytical method will be useful for enantiomer resolution of other ${\alpha}$-amino acid esters as benzophenone Schiff base derivatives.

• 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.

• 분석과학
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• 제36권4호
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• pp.143-151
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• 2023

Considering the greater role of α-amino acids in our daily lives, the enantiomer resolution of seven α-amino acids derivatized with fluorogenic reagent (4-fluoro-7-nitro-2,1,3-benzoxadiazole, NBD-F) by chiral HPLC on amylose or cellulose trisphenylcarbamate derived chiral stationary phases (CSPs) under simultaneous ultraviolet (UV) and fluorescence (FL) detection was performed. The degree of enantioseparation and resolution was affected by nature and selector backbones of the CSPs as well as the kind of amino acids. Baseline enantiomer separation and resolutions were observed for the enantiomers of all analytes as NBD derivatives especially on coated type amylose tris(3,5-dimethylphenylcarbamate) derived CSPs (Chiralpak AD-H and Lux Amylose-1). The other CSPs also showed good enantioselectivity except for the CSPs (Chiralpak IB, Chiralcel OD-H and Lux Cellulose-1) having cellulose tris(3,5-dimethylphenylcarbamate) as chiral selectors. The developed analytical chiral method was applied to determine the enantiomeric purity of seven commercially available L-α-amino acids and the impurities as D-forms were found to be in the range 0.08-0.87 %, respectively. The intra- and interday accuracy and precision assays showed high accuracy and precision of the developed analytical method. This chiral HPLC method for the enantiomer resolution of amino acids using fluorescent derivatization could be useful for the determination of enantiomeric purity of pharmaceuticals and biological study for amino acid type compounds among chiral drugs.

• 분석과학
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• 제7권1호
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• pp.41-52
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• 1994

아미노산 중 alanine, threonine, isoleucine, leucine, aspartic acid, methionine, glutamic acid, tyrosine을 대상으로 열처리, 산처리, UV 광선 조사, 효소(trypsin)의 영향을 살펴보고 6N-HCl, $105^{\circ}C$로 가열했을 때 이성화하는 정도를 측정하였다. 또한 Mass Spectrometer를 이용할 때 각 아미노산의 fragment되는 과정을 조사하여 GC에서 서로 겹칠 때 분석하는 법을 개발하였다. HPLC에서 cyclodextrin bonded phase를 이용해서 dansyl amino acid의 분리를 시도하였다.

• 분석과학
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• 제22권4호
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• pp.313-318
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• 2009

다당유도체를 기초로 하는 키랄 컬럼들을 사용하여 여러 amino alcohol의 거울상 이성질체를 산 또는 염기 등의 첨가제가 포함된 이동상에서 액체크로마토그래피로 광학분리를 수행하였다. 산 또는 염기 등의 첨가제가 각각 포함된 이동상뿐만 아니라 사용한 키랄 컬럼에 따라 광학분리된 선택성과 분리 인자가 크게 영향을 받았다. 특히 Chiralcel OD 컬럼에서 이동상에 0.1% trifluoroacetic acid를 산 첨가제로 사용했을 경우 0.1% triethylamine을 염기 첨가제로 사용했을 경우보다 머무름인자 값은 더 작게 나타났지만 광학분리의 선택성과 분리인자는 크게 증가됨을 보여주었다. 또한 Chiralcel OD 컬럼에서 이동상에 0.05% trifluoroacetic acid와 0.05% triethylamine을 함께 사용했을 때 광학분리의 선택성과 분리인자가 어느 이동상 조건보다도 가장 좋은 광학분할 결과를 보여주었다.