## 3 Isotherm Models
### Examples  
Some characteristic examples of literature will be given below. It is interesting that in many cases the adsorption results were fitted in two or more models comparing the fitting parameters. [PERSON] and [PERSON] [81] studied the preparation of MIP-poly(4-vinylpyridine-co-divinylbenzene) (poly(4-VP-co-DVB)) as the specific receptor of creatinine by heated polymerization. The monomer used in that case was 4-Vinylpyridine. The other reagents for synthesis were creatinine (template) and divinylbenzene (cross-linker). The equilibrium rebinding data were fitted using Langmuir equation and gave 11.95 mg/g maximum theoretical capacity.  
[PERSON] _et al._[82] developed a novel synthesis procedure for MIPs. The polymerization was initiated by \(\gamma\)-radiation, but using as template molecule (\(\pm\))-menthol. The evaluation of the adsorption results were done comparing the isotherms camphor (model molecule for testing) and menthol from \(n\)-hexane. The results isotherms seemed to be as those of Langmuir.  
[PERSON] _et al._[83] prepared a molecularly imprinted polymer of morphine was prepared through thermal radical copolymerization of methacrylic acid and ethylene glycol dimethacrylate. A MIP assay was also synthesized (using mainly colorimetric reporter) was in order to observe and record the adsorption isotherm of morphine imprinted polymer binding. The adsorption isotherms fitted to Langmuir equation.  
[PERSON] and co-workers [84] investigated the adsorption isotherms of polymers prepared by imprinting them with 2,4,5-trichlorophenoxyoxyacetic acid (2,4,5-T). The polymers were prepared by thermoinduced polymerization of template mixtures, 4-vinylpyridine and ethylene dimethacrylate. The experimental adsorption isotherms were fitted by using several isotherm models, and the L-F model was found to give the best fitting.  
[PERSON] _et al._[75] studied the adsorption isotherms of d- and l-phenylalanine anilide (PA) on an l-phenylalanine anilide imprinted stationary phase have been determined using staircase frontal analysis. It was found that the adsorption data fit well to both the Freundlich and the Bi-Langmuirisotherm models. Examination of the best values of the numerical coefficients of the Bi-Langmuir model shows that the site class representing the binding sites with the highest binding energy exhibits a very low saturation capacity for the non-imprinted enantiomer, indicating a high selectivity for the imprinted l-enantiomer.  
[PERSON] and [PERSON] [85] synthesized cholesterol-imprinted polymers in bulk polymerization by the methods of covalent and non-covalent imprinting. For the covalent imprinting, the combination of template/monomer was cholesteryl (4-vinyl)phenyl carbonate, while for the non-covalent imprinting the respective combination was methacrylic acid or 4-vinylpyridine. The equilibrium data were successfully fitted to L-F model.  
[PERSON] _et al._[86] investigated the binding of l-Boc-phenylalanine anilide (BFA) and l-Boc-phenylalanine (phe) to molecularly imprinted and non-imprinted polymer nanoparticles consisting of poly[(ethylene glycol dimethacrylate)-co-(methacrylic acid)] by adsorption experiments and mathematical modeling. The isotherms have been fitted using the Freundlich, L-F, bi-Langmuir, Langmuir and extended Langmuir model.