Chiral separation with ligand-exchange micellar electrokinetic chromatography using a D-penicillamine-copper(II) ternary complex as chiral selector.
D-Penicillamine is demonstrated for the first time as a chiral ligand for the enantioseparation of dansyl amino acids based on ligand-exchange micellar electrokinetic chromatography (LE-MEKC). Copper(II) was used as the central ion in the ternary complex. The effect of surfactant on the resolution was significant. A concentration of 20 mM sodium dodecyl sulfate (SDS) was shown to be necessary for the separation. Other important parameters, such as the concentration ratio of D-penicillamine (D-PEN) to Cu2+, the kind of metal central ion, the type and pH value of buffer, were also investigated. N-Acetyl-D-penicillamine and L-valine (Val), with similar structure to D-penicillamine, were applied as their copper(II) complexes as chiral selector and the chiral recognition mechanism is briefly discussed. Under optimum experimental conditions, i.e., 20 mM NH4OAc, pH 6.5, a 2:1 concentration ratio of D-penicillamine to Cu(II), 4 mM CuSO4 and 8 mM D-penicillamine, the chiral separation of eight pairs of different dansyl amino acid enantiomers was accomplished with resolution ranging from 1.1 to 5.9. When L-PEN was used instead of D-PEN, reversal of the migration order was observed.
Zheng
Zhi-Xia
ZX
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
Lin
Jin-Ming
JM
Qu
Feng
F
Hobo
Toshiyuki
T
D000596:Amino Acids / Q000737:chemistry*; D002021:Buffers; D020374:Chromatography, Micellar Electrokinetic Capillary; D003300:Copper / Q000737:chemistry*; D008823:Micelles; D010396:Penicillamine / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013237:Stereoisomerism; D013501:Surface-Active Agents / Q000737:chemistry*
D000596:Amino Acids; D002021:Buffers; D008823:Micelles; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D003300:Copper; D010396:Penicillamine