Chiral analysis of derivatized amino acids from kefir by gas chromatography

MENESTRINA, F.; OSORIO GRISALES, J.; CASTELLS, C. B.

MICROCHEMICAL JOURNAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 128 p. 267 - 273

0026-265X

Theamino acids presentin the kefir sampleswere derivatized using different alkyl chloroformates combined withalcohols and chromatographed on a(3-O-butanoyl-2,6-di-O-pentyl)-γ-cyclodextrin(Lipodex E) chiral gas-liquid chromatographic column. The combinationof derivatization reagents that led to better chromatographicperformance for standard amino acid solutions was criticallycompared. All the chloroformate/alchohol mixtures lead to fast andquantitative reactions.However,theethyl chloroformate/ethanolmixture was selected sincethe number of enantioseparated amino acid derivatives was higher.The derivatization was applied to samples of kefir grains grown in raw and in skimmedUHT milk. The samples were previously pretreated byelution froma lowpressure ion-exchange columns. Standard addition calibration curveshave been usedfor the quantitative determinations of aminoacid derivatives in both samples, and the figures of merit of theproposed method have been assessed. TheL- and D- configuration of D- and L-alanine, D- and L-valine,D-proline, L-threonine, aspartic and glutamic acids, methionine andcysteine were detected and quantitatively determined.