Effect of content of chiral selector and pore size of core-shell type silica support on the performance of amylose tris(3,5-dimethylphenylcarbamate)-based chiral stationary phases in nano-liquid chromatography and capillary electrochromatography.

In this study the separation performance of various chiral stationary phases (CSPs) made of polysaccharide-based chiral selectors coated onto superficially porous (core-shell or fused-core) silica supports were evaluated. The CSPs obtained by coating of various amounts of chiral selector (1-5%) onto supports of various pore size (100 and 300 Å) were studied. Their evaluation was pursued in both chiral nano-liquid chromatography (nano-LC) and chiral capillary electrochromatography (CEC). Among the goals of this study was to re-examine our previous unexpected finding of better performance of superficially porous CSP under CEC conditions compared to nano-LC conditions for a new set of chiral compounds, as well as to study the effect of varying the chiral selector content and nominal pore size of supporting silica on the performance of core-shell silica-based polysaccharide-type CSPs. Based on the results of this study it can be seen that CSPs based on superficially porous silica can successfully be used for the separation of enantiomers in both nano-LC and CEC mode. Only a slight advantage of CEC over nano-LC mode was observed in this study from the viewpoint of plate numbers, especially at higher mobile phase flow rates. It must also be noted that the optimal theoretical plate height is still too high and further optimization of superficially porous CSPs is necessary for both nano-LC and CEC applications.