Mobile Phases for Size-Exclusion Chromatography

Mobile phases for SEC fall into two broad categories aqueous buffers for GFC and organic solvents for GPC. In SEC, the mobile phase is selected not to control selectivity but for its ability to dissolve the sample. In addition, the mobile phase should have a low viscosity and be compatible with the detector and column packing. For example, polar solvents such as methanol 

It is also important that the mobile phase be chosen to prevent interaction of the sample components with the surface of the packing by adsorption or other unwanted effects. Non-size-exclusion effects in GFC, such as those shown in Table 2.6, can usually be avoided by selecting proper combinations of stationary and mobile phases.55 Similarly, in GPC solvents that reduce these interactions, such as toluene or tetrahydrofuran, are commonly used. When these solvents cannot be used, salts such as lithium bromide may be added. 

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