Recent accomplishments in the field of enantiomer separation by CEC

Abstract

Recent accomplishments in the field of enantiomer separation by CECThe present review intends to summarize recent developments in the field of enantioselective separations and analysis by CEC. It covers studies published in English language in common peer-reviewed journals within the period between 2003 and 2006. Both, methods making use of chiral mobile phase additives as well as chiral stationary phases for electrochromatographic enantiomer separations, are reviewed. Achievements that have been made on the various column technologies, such as open-tubular, particle-packed, inorganic, organic and particle-fixed (hybrid-type) monolithic as well as molecularly imprinted polymer phases, are discussed.

Use of coated capillaries for the electrophoretic separation of stereoisomers of a growth hormone secretagogue

“…Enantiomeric separations with CDs in capillaries coated with a polyelectrolyte multilayer has been reported [67,68] but in this case the CD used was neutral and therefore no coating of the capillary with the CD itself as in this study was observed. No further attempts were achieved in this study to optimize the thickness of the adsorbed CD layer which may enhance enantiorecognition [63].…”

“…Unfortunately, the stereoisomers were co-migrating in the absence of HS-g-CD in the BGE, their interaction with the HS-g-CD of the coating being not sufficiently enantioselective. This is probably due to the thin stationary phase film obtained resulting in a low sample capacity [63]. This result is however very interesting since it shows that this type of coating could dramatically alter the mobility and thus the separation of chiral or non-chiral analytes.…”

Open-tubular Electrochromatographic Chiral Separation of Amino Acids Using an Organic Nanocrystals Immobilized Capillary

“…In CEC, the chiral selectors are immobilized in packed, monolithic or open-tubular (OT) capillaries. [8][9][10][11] Besides, both the high efficiency of CE and the high selectivity of HPLC are coupled in CEC; the immobilization of the chiral selectors onto the packed, monolithic materials or the inner surface of the capillary can avoid the UV background, according to the selector. Preinerstorfer et al have reported the preparation of a monolithic silica capillary column modified with cinchona alkaloid derivatives to separate dipeptides in non-aqueous CEC.…”

Macrocyclic polyamine‐modified poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) monolith for capillary electrochromatography

“…The other option is the postmodification approach, in which a monolith with reactive groups, such as the epoxide groups of glycidyl methacrylate (GMA), is modified by reacting with various chromatographic ligands such as amino acid [6], chiral selector [7], N-ethylbutylamine [8], and affinity ligand [9]. There are considerable advantages for this approach [10,11]: firstly, the reactive monolith that allows a subsequent modification has to be optimized only once. In addition, the bonded ligands are fully exposed to the interface between the stationary phase and the mobile phase, which is favorable for chromatographic interactions.…”