Evidence for molecular recognition

Evidence for a specific inclusion process promoted by molecular imprinting is directly given through sensor effects in comparison to non-imprinted layers of equivalent height. Detailed interpretation of specific inclusion or non-specific adsorption phenomena is accessible with the Brunauer-Emmett-Teller (BET) isotherm adsorption analysis [18] a typical BET-isotherm is shown in Fig. 21.2. 

The adsorption analysis can be performed using the experimental sensor effect data from gravimetric QCM measurements. The frequency shift, which is proportional to the partial pressure of the analyte, is correlated to the number of specific incorporation sites in the linear range of the isotherm slope. Additional evidence for specific interactions between the analyte and the polymer matrix can be demonstrated using infrared spectroscopic analysis [19]. NMR [4,7] can also provide information about imprinting effects. 

The presented methods of examination focus on a comprehensive understanding of the imprinting effect. However, a reliable rule-based mechanism to predict the potential of target MIP structures for sensory applications is still not available and often, only experimental evaluations of MIPs provide useful rules of thumb for the development of selective coatings. 

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