Enantiomeric separations by use of calixarene electrokinetic chromatography
Chiral acylcalixarene amino acid derivatives have been synthesized and used as pseudostationary phases in capillary electrophoresis (CE). Use of these calixarene (CX4) derivatives with electrokinetic capillary chromatography (4-EKC) resulted in enantioseparation of three binaphthyl derivatives at pH values above 7. The structures of the CX4 derivatives, i.e., (N-L-alaninoacyl)calix-arene (CX4-L-Ala) and (N-L- valinoacyl)calixarene (CX4-L-Val), and the buffer pH were found to be important factors in chiral separation. When CX4-L-Ala was used as a pseudostationary phase in the CE buffer, baseline resolution was achieved for 1,1'-bi-2-naphthol (BINOL) and 1,1'-binaphthyl-2,2'-dismine (BNA). The addition of sodium dodecyl sulfate (SDS) to the CX4-L-Ala solution resulted in baseline resolution of the enantiomers of 1,1'-binaphthyldiyl hydrogen phosphate (BNHP). In contrast, chiral separations of BNHP, BINOL, and BNA were successfully achieved in a single run with use of CX4-L-Val as a chiral selector in the absence of SDS. The utility of these new chiral selectors for chiral separation in CE is compared and discussed in detail.
Publication Source (Journal or Book title)
Peña, M., Zhang, Y., & Warner, I. (1997). Enantiomeric separations by use of calixarene electrokinetic chromatography. Analytical Chemistry, 69 (16), 3239-3242. https://doi.org/10.1021/ac961319y