Preparation of Ion Exchange Supports

Independent from the chemical nature of the supports, pre-cycle lEC media before use to obtain optimal separations. The precycling is recommended especially before first use and after longer storage. 

After pre-cycling equilibrate the lEC medium with starting buffer. Because a simple washing with a tenfold bed volume of starting buffer is not sufficient, use one of the both following methods. 

Suspend the gel in a buffer with the same pH as the starting buffer, but tenfold concentrated with respect to the buffering counterion (anion exchange medium, e.g., phosphate). Pour the gel into the column after 15 min and wash it with 10 ml starting buffer per gram wet weight. 

Suspend the gel in the starting buffer. Adjust the pH of the slurry after 10 min with acid or base until the pH of the starting buffer is obtained. When the pH is stable, pour the gel into a column 

The capacity indicated in Table 3.2 is for orientation only and differs from protein to protein therefore, check the capacity in an assay with the same conditions as for separation and monitoring. 

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