Packing Materials and Hardware

Column packing is as much art as it is science. Even the professionals in the held cannot routinely prepare columns that will give the same plate count column to column. They quality control the columns with a set of standards, and columns that deviate by more than a set amount are either dumped and repacked (not cost effective) or are sold as specialty columns. Columns that exceed QC specifications are almost as bad as poor efficiency columns  

You may find that for teaching purposes that packing your own columns may be cost effective. An analytical column holds about 3 g of packing and the column itself can be dumped, cleaned, and reused. However, I would recommend not packing your own research columns. I will show you ways of extending the lifetimes of your columns enough that commercial columns could be cost effective. 

A number of commercial column packing apparatuses are available. One type, the ascending type, is a stirred can that pumps slurry upward into the pressure line and then down into the column. The descending type of packer is simply a slurry reservoir that attaches in place of the inlet end-cap and frit and is equipped with a pump connection at the top (Fig. 5.3). Manufacturers use 20,000-psi pumps to drive slurry into the column, but most laboratory packing apparatuses rely on pumps that reach a maximum of only 6,000-10,000psi. The pumps are run fully open until the pressure stabilizes. 

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