Page 189 - Chiral Separation Techniques

6.5 Adsorption–Desorption Kinetics and Chromatographic Band Broadening 167

6.6.1 Factors Related to the Monomer-Template Assemblies

It is of obvious importance that the functional monomers interact strongly with the
template prior to polymerization, since the solution structure of the resulting assem-
blies presumably defines the subsequently formed binding sites. By stabilizing the
monomer–template assemblies, it is possible to achieve a large number of imprinted
sites. At the same time, the number of nonspecific binding sites will be minimized,
since free functional monomer not associated with the template is likely to be acces-
sible for binding. Considering one particular binding site, the following factors have
been identified that are likely to affect the recognition properties of the site (Fig. 6-8).

Fig. 6-8. Factors affecting the recognition properties of MIPs related to the monomer template
assemblies.

The strength and positioning of the monomer–template interactions are of impor-
tance for materials with good molecular recognition properties to be obtained. The
broad applicability of MAA as a functional monomer is related to the fact that the
carboxylic acid group serves well as a hydrogen bond and proton donor and as a
hydrogen bond acceptor [56]. In aprotic solvents such as in acetonitrile carboxylic
acids and amine bases form contact hydrogen-bonded assemblies where the associ-