• KSBB Journal
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• v.28 no.6
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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.

• Bulletin of the Korean Chemical Society
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• v.29 no.8
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• pp.1601-1604
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• 2008

• Analytical Science and Technology
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• v.36 no.4
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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.

• Analytical Science and Technology
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• v.24 no.3
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• pp.225-230
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• 2011

Anatoxin-a is a cyanobacterial neurotoxin with a high toxicity produced by Anabaena, Aphanizomenon and Oscillatoria. Water bloom, formed by Anabaena has been occurring frequently in Lake Yeongchun. It is need to develop a sensitive method for determination of anatoxin-a to control potential hazard in raw water resources. In this study, we developed a highly sensitive analytical method of anatoxin-a using solid phase extraction (SPE) and high performance liquid chromatography (HPLC) with fluorescence detection. Anatoxin-a was converted into a highly fluorescent derivative using 4-fuoro-7-nitro-2,1,3-benzoxadiazole (NBF-F). The method was evaluated in terms of linearity of calibration curve, recovery and repeatability, and the adequate values were obtained. The method detection limit was $0.034\;{\mu}g/g$ and $0.022\;{\mu}g/L$ for algal and water samples, respectively. The concentrations of anatoxin-a were measured in algal and water samples from Lake Andong, Yeongchun and Daechung and ranged from $0.135\;{\mu}g/g$ to $10.979\;{\mu}g/g$ in algal samples and not detected in water samples.