Determination of the enantiomers of alpha-hydroxy- and alpha-amino acids in capillary electrophoresis with contactless conductivity detection.
The enantiomers of the anions of five alpha-hydroxy acids, namely lactic acid, alpha-hydroxybutyric acid, 2-hydroxycaproic acid, 2-hydroxyoctanoic acid and 2-hydroxydecanoic acid, as well as the two alpha-amino acids aspartic acid and glutamic acid, were baseline separated and detected by CE with contactless conductivity detection. Vancomycin was employed as chiral selector and could be used with conductivity detection without having to resort to a partial filling protocol as needed when this reagent is used with UV absorbance measurements. The procedure was successfully applied to the determination of the lactic acid enantiomers in samples of milk and yogurt. Linearity was achieved in the concentration range of 10-500 micromol/L with good correlation coefficients (0.9993 and 0.9990 for L- and D-lactic acid, respectively). The LODs (3 S/N) for L- and D-lactic acid were determined as 2.8 and 2.4 micromol/L, respectively.
Pormsila
Worapan
W
Department of Chemistry, University of Basel, Basel, Switzerland.
Gong
Xiao Yang
XY
Hauser
Peter C
PC
D000596:Amino Acids / Q000032:analysis* / Q000737:chemistry; D000818:Animals; D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000379:methods*; D005504:Food Analysis; D006880:Hydroxy Acids / Q000032:analysis* / Q000737:chemistry; D019344:Lactic Acid / Q000032:analysis / Q000737:chemistry; D016014:Linear Models; D008892:Milk / Q000737:chemistry; D013237:Stereoisomerism; D015014:Yogurt / Q000032:analysis
D000596:Amino Acids; D006880:Hydroxy Acids; D019344:Lactic Acid