HPLC enantioseparation on composite chiral stationary phases based on homosubstituted and heterosubstituted amylose derivatives.

Coated-type composite chiral stationary phases (CSPs) based on homosubstituted (same substituents introduced onto the glucose unit) and heterosubstituted (different substituents grafted onto the glucose unit) amylose derivatives were prepared and their enantioseparation capabilities in high-performance liquid chromatography were evaluated. Investigations demonstrated that the enantioseparation capabilities of the composite CSPs generally fell in between those of the two single-component CSPs. Notably, several chiral analytes that failed to achieve resolution on the single-component CSPs were successfully discriminated on the composite ones, thereby extending the application scope of an individual amylose derivative-based CSP. Some anomalous retention and selectivity behaviors were also observed on the composite CSPs, which may be due to some interactions between the two polymers during cocoating. Additionally, the impact of mobile phase composition on enantioseparation was examined. In the hexane/2-propanol (80/20, 90/10, and 95/5, v/v) mobile phase system, a lower 2-propanol content in the mobile phase always results in higher retention factor k1, whereas the separation factor α does not change significantly, with the maximum variation of racemate 2 being approximatley 16%.