Size-exclusion chromatography peak capacity

The effect of temperature on column efficiency, however, is frequently exploited, particularly in size exclusion chromatography (SEC). As has already been discussed, high efficiencies are essential in SEC due to the limited peak capacity of the column and consequently, the very small separation ratios. However the effect of temperature on column efficiency is not well understood by many analysts and consequently, will be discussed in some detail. It was shown on page... 

The main disadvantage of size-exclusion chromatography is its low peak capacity, which arises from the small elution volumes of the peaks. In addition because peak dispersion is small, extra-column contributions to band broadening in size-exclusion chromatography have to be kept to a minimum. The relative contribution of extra-column band broadening can be minimized by the use of small particles = 3-10 pm) and long (L = 50 100 cm), wide-bore (d = 8-10 mm) columns. 

Size-exclusion chromatography (SEC) is a method in which molecules are separated by size due to differential permeation into a porous support. It requires complete solubility of the analytes in the mobile phase and elimination of all interactions with the bonded phase. In these respects, SEC is not as useful for the separation of peptides as it is for proteins because peptides vary drastically in solubility, charge, and hydrophobicity. Peak capacity in SEC is fairly low compared to other HPLC methods because all separations must occur in the internal volume (Vi) of the support, which is generally less than half the volume of mobile phase in the column. Despite these deficiencies, SEC can be very effective for separating peptides from dimers, aggregates, small molecules, proteins, and other molecules which differ by size. 

The smaller the particle size of the stationary phase the greater is the peak capacity of the column and the better and faster are the separations. Size-exclusion chromatography is generally subdivided further into mobile phase categories. The mobile phase is aqueous in GFC (gel filtration chromatography) and is an organic solvent in GPC (gel permeation chromatography). 

Size-exclusion chromatography is a method in which molecules are separated by size due to differential permeation into a porous support. This technique is especially useful for the separation of proteins because they are macromolecules frequently found in the presence of smaller and larger species. The peak capacity in SEC is fairly low compared to other HPLC methods because all separation must occur in the internal volume of the support,... 

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