Factor of Solution

Figure 5. Screen factor of solutions of hydrolyzed poly(starch-g-(2 propenamide)) copolymer.

The use of cyclodextrins as the mobile phase components which impart stereoselectivity to reversed phase high performance liquid chromatography (RP-HPLC) systems are surveyed. The exemplary separations of structural and geometrical isomers are presented as well as the resolution of some enantiomeric compounds. A simplified scheme of the separation process occurring in RP-HPLC system modified by cyclodextrin is discussed and equations which relate the capacity factors of solutes to cyclodextrin concentration are given. The results are considered in the light of two phenomena influencing separation processes adsorption of inclusion complexes on stationary phase and complexation of solutes in the bulk mobile phase solution. 

Table I. Capacity factors of solutes (kl), calculated capacity factors of their P>-CD complexes (kn.g nn) and stability constants (Kj of -CD complexes of cresoles, p-nitrocinnimic acids and enantiomers of mandelic acid, mephenytoin and hexobarbital. Stationary phase 10 pm LiChrosorb RP 18...

The effect of pH on the retention factors of solutes, eluted with an anionic surfactant, is very similar on Cl8 columns to that obtained using cyano columns, when hydrophobic interactions dominate. However, less hydro-phobic and negatively charged solutes will elute very quickly on C18 columns, because of repulsion from both micelles and negatively charged modified stationary phase. Fig. 5.11 shows plots of k vs. pH with the typical... 

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