The separation of D/L amino acid pairs by high-performance liquid chromatography after precolumn derivatization with optically active naphthylethyl isocyanate.
A method for determining the optical purity of amino acids using HPLC and precolumn derivatization is described. (+)-1-(1-Naphthyl)ethyl isocyanate reacts with racemic amino acids, in high yield, to form naphthylethyl carbamoyl derivatives. The resulting diastereoisomeric pairs were separated on reversed-phase C18 columns and detected fluorometrically. Excitation maxima for naphthylethyl carbamoyl aspartic acid were 235 and 297 nm. The emission maximum was at 333 nm. Using a filter fluorometer with a zinc or cadmium lamp, less than 1 pmol of a D amino acid can be measured in the presence of 1000-fold excess of the L isomer. The column can also be monitored at lower sensitivity, using an ultraviolet detector operating at or near the absorption maximum of 222 nm. Chromatographic data are presented on the resolution of 17 amino acid pairs.
Nathan S. Kline Institute for Psychiatric Research, Center for Neurochemistry, New York, New York 10035.
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Dunlop
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Neidle
D000596:Amino Acids / Q000302:isolation & purification*; D001224:Aspartic Acid / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D003485:Cyanates; D007202:Indicators and Reagents; D017953:Isocyanates; D009281:Naphthalenes; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism
D000596:Amino Acids; D003485:Cyanates; D007202:Indicators and Reagents; D017953:Isocyanates; D009281:Naphthalenes; D001224:Aspartic Acid; C054308:1-(1-naphthyl)ethyl isocyanate