Page 203 - Chiral Separation Techniques

6.10 Conclusions 181

Fig. 6-17. Cast-imprinted membranes. (From Yoshikawa et al. [103].)

6.10 Conclusions

A number of conditions will directly influence the development of a new MICSP.
The availability of the template in preparative amounts will determine whether it will
have to be recycled, or a template analogue must be used. The latter alternative
should also be considered in cases where the template is unstable or poorly soluble
in the monomer mixture. Depending on the format of the separation, the polymer
must meet certain requirements. If the material is to be used as a HPLC stationary
phase, then monodisperse spherical particles are desirable and rapid adsorption–des-
orption of the template to the sites is necessary for high-performance separations.
However, broad and asymmetric band shapes and low saturation capacities due to the
heterogeneous distribution of binding sites and slow mass transfer processes are
important problems that strongly limit the possible applications of these phases in
analytical and preparative chromatography. The use of imprinted polymers in a foam
flotation apparatus or in membrane separations have been demonstrated, although
probably also here no viable application can be expected in the near future. Never-
theless, with designed functional monomers, new polymerization techniques and
combinatorial synthesis and screening techniques, MICSPs that meet the above-
mentioned requirements may soon be a reality.

Acknowledgment

The author is grateful to Dr. Francesca Lanza for assistance in preparing the
manuscript.