Organic polymer monoliths

Svec, E (2004a). Preparation and HPLC applications of rigid macroporous organic polymer monoliths. J. Sep. Sci. 27, 747-766. 

In comparison to their silica counterparts, organic polymer monoliths generally exhibit lower efficiencies in the reversed-phase HPLC separation of small molecules. This reduced performance is primarily due to the lack of mesopores (see Section 1.3.2.5) and the presence of micropores in the polymer matrix, which cause slow internal diffusion. However, there are some promising approaches trying to accomplish the chromatography of small molecules on organic polymer monoliths. 

Svec, R, Organic polymer monoliths as stationary phases for capillary HRLC, Journal of Separation Science 27(17-18), 1419-1430, 2004. 

Li, Y., Chen, Y., Xiang, R., Ciuparu, D., Pfefferle, L. D., Horwath, C., and Wilkins, J. A., Incorporation of single-wall carbon nanotubes into an organic polymer monolithic stationary phase for mu-HPLC and capillary electrochromatography, Analytical Chemistry 77(5), 1398-1406, 2005. 

Mini-columns for analyte separation/concentration can also behave as reactors, resembling the packed bed reactor. In this context, organic polymer monoliths, largely used in the medical and biological fields [73], should be highlighted. Monolithic mini-columns consist of continuous beds with macropores and mesopores which are characterised by low back-pressure effects. These columns offer several other advantages [74], as emphasised in Chapter 8. In the context of flow analysis, monolithic mini-columns were implemented in a sequential injection analyser in 2003 [75] and the potential and limitations of the approach, called Sequential Injection Chromatography, were recently reviewed [76]. 

In the early 1990s, yet another category was developed. These rigid macroporous organic polymer monoliths were formed by a very simple in situ molding process in which a liquid mixture of monomers and solvents was polymerized under carefully controlled conditions and immediately used within a closed tube or similar container. Many review artieles describing various aspects of these materials have been published during the years since their inception. ... 

The breakthrough in the development of organic polymer monoliths for use in conventional anion-exchange chromatography of common inorganic anions and organic acids was made possible by several new advancements including as follows ... 

Proteins are isolated and characterized with different chromatographic techniques. Depending on the protein, ion-exchange (lEX), size-exclusion (SEC), affinity (IMAC), hydrophobic interaction (HIC), and reversed-phase chromatography (RPLC) may be applied. Traditionally, separation materials with low mechanical stability and limited resolution were used. In recent years, HPLC materials were developed that offered the separation power required by the protein chemist. Now, pellicular ion-exchange resins as well as organic polymer monoliths exhibit high resolution at relatively short retention times, while... 

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