Size-exclusion chromatography polymeric packings

High-performance size exclusion chromatography is used for the characterization of copolymers, as well as for biopolymers (3). The packings for analyses of water-soluble polymers mainly consist of 5- to 10-/Am particles derived from deactivated silica or hydrophilic polymeric supports. For the investigation of organosoluble polymers, cross-linked polystyrene beads are still the column packing of choice. 

Size exclusion chromatography (SEC, also known as GPC and GFC) has become a very well accepted separation method since its introduction in the late-1950s by works of Porath and Flodin (1) and Moore (2). Polymers Standards Service (PSS) packings for SEC/SEC columns share this long-standing tradition as universal and stable sorbents for all types of polymer applications. In general, PSS SEC columns are filled with spherical, macroporous cross-linked, pressure-stable, and pH-resistant polymeric gels. 

The last part of the book, Chapters 10—17, reports on different applications of polymers in the field of analytical chemistry sorption of organic compounds, Hke phenols, pesticides or caffeine, the use of polymeric materials for size-exclusion chromatography, for HPLC packing materials or as solid phase extraction sorbents. The examples cover a broad variety of chemical compounds, fike pesticides, pharmaceuticals, organic acids in different matrices, such as food, biological fluids, non-aqueous media, air and the use of hemosorbents in blood purification. 

Divinylbenzene- or styrene-divinylbenzene-based packings were originally developed for the size-exclusion chromatography of industrial polymers (16). They are prepared via radical polymerization of the monomers. The monomers... 

Neutral hydrophilic polymeric packings are also useful for HILIC (6). Examples are the hydrophilic methacrylate phases, which were originally designed for aqueous size-exclusion chromatography. The surface of these packings consists of polyol groups, which are very hydrophilic. These phases tend to be more retentive than silica-based bonded phases. 

Suppliers of polymeric packings for aqueous size-exclusion chromatography are Polymer Labs (Plgel, UK), Showa Etenko (Shodex OHpak, Japan), Tosoh (TSKgel PW, Japan), and Waters (Ultrahydrogel, USA). 

Size Exclusion Chromatography (SEC) uses columns packed with a porous, inert material (with pore dimensions similar to the dimensions of the macromolecules to be analyzed) which does not interact with the polymer. The SEC method is based on the fact that when a polymeric solution is in the presence of a porous particle, smaller polymer molecules penetrate the pores more deeply than the larger ones. 

Because these crosslinked polystyrene beads have pore sizes that are controlled by suspension polymerization parameters and the crosslinking density of the polymer, they are being used as column packing materials for size-exclusion chromatography, also known as gel permeation chromatography (GPC). The crosslink density increases with increased divinyl benzene concentration. 

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