Size exclusion chromatography advantages

In addition to the insoluble polymers described above, soluble polymers, such as non-cross-linked PS and PEG have proven useful for synthetic applications. However, since synthesis on soluble supports is more difficult to automate, these polymers are not used as extensively as insoluble beads. Soluble polymers offer most of the advantages of both homogeneous-phase chemistry (lack of diffusion phenomena and easy monitoring) and solid-phase techniques (use of excess reagents and ease of isolation and purification of products). Separation of the functionalized matrix is achieved by either precipitation (solvent or heat), membrane filtration, or size-exclusion chromatography [98,99]. 

The present experimental approach is based on the chromatographic advantages provided by the diol or glycerol derivatives of porous silica stationary phases available for use in HPLC. These have recently become available for estimating the molecular size of polyelectrolytes using aqueous size exclusion chromatography. The conditions for reproducible polyelectrolyte size measurements, and their possible purturbations have been summarized by Barth (8). 

The DEBS 1-TE mini-PKS offers several advantages over the complete three-protein DEBS system for studies in vitro. Most importantly, it is a single protein whose size (MW —390 kDa) makes it amenable to purification by size-exclusion chromatography. And unlike the three DEBS proteins, purified DEBS 1-TE can function autonomously to catalyze two complete condensation cycles to give a lactone product. Finally, the lactone incorporates much of the functionality and stereochemistry present in the macrolide, but is significantly easier to analyze than 6-dEB by various techniques such as GC-MS and H NMR. DEBS 1 -TE can therefore serve as a convenient model system for the far more elaborate... 

Ball, D. Thornton, T. "Advantages of Direct Measurement of Retention Volume in Liquid Chromatography and Size Exclusion Chromatography" 32nd Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, Atlantic City, NJ, 1981 paper 357. 

It is also useful to note that the hydrophilic alcohol coated stationary phases originally designed for size exclusion chromatography such as Zorbax GF250 and PL-aquagel also work well as normal phase media. The advantage of these lies in the increased stability of the stationary phases at high pH. 

A low-angle laser light scattering (LALLS) detector was developed for use in size exclusion chromatography [133] and has been used coupled with FFF [134]. The advantage of this detector is that it can, in combination with a concentration detector (refractometer, UV/VIS, or IR photometric detector), provide direct data on molar masses of the eluted sample. 

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