Size exclusion chromatography concentration effects

Size-exclusion chromatography (SEC) is used for the separation of large molecules according to their effective size in solution. In combination with ICP-MS it allows the molecular weight of biomolecules in nondenaturing conditions to be estimated, and it is frequently employed when dealing with complex samples for fractionation purposes, that is, for the identification of various classes of species of an element and to determine the sum of its concentrations in each class. 

The high salt concentrations used can present a challenge for the HPLC equipment. Pumps with seal-wash are prrferred. If chloride buffers are used, HPLC systems with nonmetallic fluid paths are recommended. It is also advisable to flush the salt solution out of the system when it is not in use. Temperature and pH can affect the separation and should therdbre be controlled. But both the temperature effect and pH effect are smaller than in other forms of chromatography (with the exception of size-exclusion chromatography). 

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