Polymer-based monoliths

Three main types of polymer-based monoliths are polymethacrylate-based monoliths where methacrylate forms the major component of the monomers for polymerization, polyacrylamide-based monoliths where cross-linked polyacrylamide is synthesized directly within the capillary, and polystyrene-based monoliths that are usually prepared from styrene and 4-(chloromethyl) styrene as monomers and divinylbenzene (DVB) as the cross-linker. 

In a related study this group also demonstrated the use of non-volatile solvents in CEC-MS without compromising the quality of spectra that has also been demonstrated using polymer-based monolithic column prepared by in situ copolymerization of butyl methacrylate with sulfonic acid functionalities. 

In addition to utilization of monoliths as a column material, two reports describing respectively silicate and synthetic organic polymer based monolithic frits were published recently [85,86], The conventional method of frit fabrication for a particle packed column usually involves thermal sintering of a section of the packing material, such as bare or octadecyl silica, using a heating device. This approach has several weaknesses such as the lack of control of the temperature and porous properties of the frit that decreases reproducibly of the fabrication process. 

Several polymer-based monolithic columns have become available commercially in different formats, e.g., disks, membranes, and LC columns with diameters in the range of 0.1-100 mm ID [52], The preparation and application of organic polymer-based monoliths have been reviewed recently [20]. 

Bioanalysis Silica- and Polymer-Based Monolithic Columns... 

A polymer-based monolith from an organic monomer with additives. 

If we can use the number of applications and published papers as a measure of success, silica- and polymer-based monoliths are certainly the winner. In part, this has come about as a result of industry getting involved and making the product available on a mass scale. The introduction of the first commercially available product, the Chromolith from Merck KGaA (Darmstadt, Germany), saw the beginning of a new routine chromatographic media. 

In recent years, the interest in using porous silica and polymer-based monolithic stationary-phase media for ion chromatographic separations of inorganic and organic ions has increased.As compared to particle bed columns, monolithic columns represent a single piece of porous cross-linked polymer or porous silica. Monoliths are made in different formats as porous rods, generated in thin capillaries or made as thin membrane or disks. 

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