Determination of Alpha-Dialkylamino Acids and Their Enantiomers in Geological Samples by High-Performance Liquid-Chromatography after Derivatization with a Chiral Adduct of O-Phthaldialdehyde

Citation:
Zhao, MX, Bada JL.  1995.  Determination of Alpha-Dialkylamino Acids and Their Enantiomers in Geological Samples by High-Performance Liquid-Chromatography after Derivatization with a Chiral Adduct of O-Phthaldialdehyde. Journal of Chromatography A. 690:55-63.

Date Published:

Jan

Keywords:

amino-acids, cretaceous-tertiary boundary, derivatives, extinction, gas-chromatography, murchison meteorite, ortho-phthalaldehyde, phases, resolution

Abstract:

Derivatization with o-phthaldialdehyde (OPA) and the chiral thiol N-acetyl-L-cysteine (NAG) is a convenient and sensitive technique for the HPLC detection and resolution of protein amino acid enantiomers. The kinetics of the reaction of OPA-NAC with alpha-dialkylamino acids was investigated. The fluorescence yield of alpha-dialkylamino acids was only about 10% of that of protein amino acids when the derivatization was carried out at room temperature for 1-2 min, which is the procedure generally used for protein amino acid analyses. The fluorescence yield of alpha-dialkylamino acids can be enhanced by up to ten-fold when the derivatization reaction time is increased to 15 min at room temperature. The OPA-NAC technique was optimized for the detection and enantiomeric resolution of alpha-dialkylamino acids in geological samples which contain a large excess of protein amino acids. The estimated detection limit for alpha-dialkylamino acids is 1-2 pmol, comparable to that for protein amino acids.

Notes:

n/a

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DOI:

10.1016/0021-9673(94)00927-2