Monolithic enantiomer‐selective stationary phases for capillary electrochromatography

Abstract

Monolithic materials have become a well-established format for stationary phases in the field of capillary electrochromatography. Four types of monoliths, namely particle-fixed, silica-based, polymer-based, and molecularly imprinted monoliths, have been utilized as enantiomer-selective stationary phases in CEC. This review summarizes recent developments in the area of monolithic enantiomer-selective stationary phases for CEC. The preparative procedure and the characterization of these columns are highlighted. In addition, the disadvantages and limitations of different monolithic enantiomer-selective stationary phases in CEC are briefly discussed.

Hybrid monolithic columns coated with cellulose tris(3,5-dimethylphenyl-carbamate) for enantioseparations in capillary electrochromatography and capillary liquid chromatography

“…The state-of-the-art in microseparation techniques has been reviewed, and it has been concluded that monolithic capillary columns are particularly suitable for both CEC and CLC because monolithic columns eliminate the need for frits retaining the stationary phase, and possess good permeability and good peak capacity [7][8][9][10][11][12]. To date, the monolithic enantiomer-selective stationary phases utilized in CEC or CLC can be classified into four categories: particle-fixed monoliths, silica-based monoliths, polymer-based monoliths and molecularly imprinted monoliths [13][14][15][16][17][18][19][20].…”

Fabrication of molecularly imprinted hybrid monoliths via a room temperature ionic liquid‐mediated nonhydrolytic sol–gel route for chiral separation of zolmitriptan by capillary electrochromatography

“…However, silica-based MIPs are often prepared by conventional hydrolytic sol-gel process [14][15][16][17][18][19][20][21][22], which often require curing and ageing at high temperature, and thus inevitably result in the poor properties of MIPs due to the cracking and the shrinkage of MIPs during drying, especially in the case of the MIP monolithic column [23]. For these reasons, earlier works on MIP monoliths in CEC focused more on organic-polymerbased and less on the silica-based hybrid [8][9][10][11][12]. An alternative approach to prepare the silica-based MIP monoliths is to anchor the MIP film coating covalently on the surface of a preprepared monolithic silica column [24] and fast association/ dissociation kinetics of the analytes with the MIP monoliths was expected.…”

“…Molecularly imprinted polymers (MIPs) with a memory for the template have the potential to be powerful materials in the separation of chiral compounds, predicting not only the recognition ability but also the elution order [3][4][5][6][7]. Organicpolymer-based MIPs are extensively applied due to their excellent pH stability and the easy availability of various monomers [8][9][10][11][12], but they may shrink or swell when exposed to different organic solvent, and thus considerably cause the deformation of the MIP receptors and decrease the recognition ability towards the template [13]. Silica-based MIPs are also widely studied since the silica matrix can offer excellent mechanical strength and good solvent resistance.…”

Recent accomplishments in the field of enantiomer separation by CEC

“…At that point the interested reader is referred to a number of reviews covering earlier studies on enantioselective separations by electromigration techniques in general (including CZE, EKC as well as CEC) [8][9][10] and by CEC in particular [11][12][13][14][15][16][17]. In more recent special review articles, attention has been given for example to electrochromatographic enantioselective separations in pharmaceutical and/or biomedical analysis [18][19][20] or on enantioselective CEC using monolithic columns [21,22]. Also the application of dedicated SOs has been reviewed.…”