## 6 Important Applications
### Continuous Porous Polymers as Stationary Phases in HPLC  
As mentioned above, the particle-form supports used as stationary phases are particularly inefficient when used in the separation of high-molecular-weight molecules, such as synthetic polymers or biological molecules, since they have diffusion coefficients by several orders of magnitude smaller than those of the low-molecular-weight solutes. This problem led to the preparation of continuous porous polymers, which usually have a high binding capacity and large pores that allow performing chromatographic separations of high-molecular-weight molecules in a few minutes. For this reason, one of the most important applications of monoliths is that as supports in different chromatography processes where polymers are prepared into either HPLC columns or fused silica capillaries. In this review, we are reporting research on the use of macroporous polymer rods in different chromatographic processes. For detailed information on this application, [PERSON] and [PERSON] [127] have recently published a comprehensive review on this subject. [PERSON] _et al._[91] reported the use of poly(methylmethacrylate-co-EGDMA) monolithic polymers modified with DEAE-dextran in the separation of proteins through the anion-exchange mode. The preparation of these supports is shown in Figure 7. Fast separation of Lys, hemoglobin and BSA on the column was achieved with these polymers within 3 min at flow rates of 1,445 cm/h. In a recent report, porous monoliths have been used as supports in the separation of proteins and peptides by size exclusion chromatography (SEC). [PERSON] _et al._[128] synthesized porous monoliths in fused silica capillary columns by photo-initiated polymerization and evaluated them in SEC separation of proteins and peptides. The monomers employed were poly(ethylene glycol methyl ether acrylate) (PEGMEA) and PEGDA as mono vinyl monomer and cross-linker, respectively. The originality of this work lies in the use of mixtures of ethyl ether and nonionic surfactants poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) (PPO-PEO-PPO, abbreviated as PEP) or PEO-PPO-PEO (abbreviated as EPE) as porogenic solvents. The nonionic surfactants were used to create a considerable portion of mesopores for size exclusion of proteins. The structures of the different compounds used in the preparation of the monoliths are shown in Figure 8. Using these polymers, the separation of proteins and peptides was achieved efficiently. [PERSON] and [PERSON] [129] reported the preparation of a convection interaction media (trade name CIM(r), BIA Separation, Ljubljana, Slovenia), an isobutyl monolithic disc to the purification of the primary alcohol oxidase (from _Aspergillus ochraceus_) by HIC. The discs were synthesized through the reaction between the CIM epoxy disc and isobutylamine. The authors showed that the enzyme was adsorbed on this column and eluted with high purity. In another study [130] the authors reported the use of long alkyl chain methacrylate monolithic polymers as stationary phases in reverse phase liquid chromatography (RPLC). The monoliths were prepared in 100 um i.d. capillaries by a radical copolymerization of stearyl methacrylate (SMA) with EGDMA with a mixture of isoamyl alcohol and 1,4-butanediol as porogenic solvent. The supports were tested in the separation of mixtures of weak acids (phenols compounds), neutral (polycyclic aromatic hydrocarbons) and basic compounds (anilines) showing a good chromatographic performance. Figure 7: The illustration of reaction between DEAE-dextran and monolithic media [91]. Reprinted with permission from Elsevier. Affinity chromatography is one of the chromatographic processes in which macroporous monoliths are most used. Thus, protein A was immobilized in a monolithic capillary column using GMA as monomer and TRIM and EgDMA as cross-linkers, respectively. The capillary affinity column obtained has been successfully applied for the rapid separation of hIgG in human serum.