Bio-Rad Aminex Organic Acid and Alcohol Analysis Columns - Manual (Page 16)

Section 6
Regeneration Procedures
6.1 Fluffing the Resin Bed
Ion exchange resins are resilient. Gentle backwashing can fluff a collapsed bed
back to its original configuration or allow entrained air spaces to redissolve. If bed
compression is severe, the column may not return to original performance.
1. Turn off the pump and let the column bed relax for about 15 min.
2. Reverse the flow direction and backwash the column at 0.1 ml/min with the
running solvent for at least 4 hr. If necessary, run overnight.
3. Return the column to original operating conditions.
4. Observe the suggested maximum flow rate.
6.2 Cleaning a Contaminated Column
Most particulate contamination from solvent, pump, injector, or sample collects on
the inlet frit of the column and can be easily removed by briefly reversing the flow
direction. This procedure is sometimes effective for removal of microbial
contamination as well.
1. Reverse the flow direction and backwash the column at 0.1 ml/min for at least
4 hr, using the appropriate cleaning solvent.
2. Continue the backwash with the appropriate regenerating solvent for an
additional 4 hours.
3. Return the column to original operating conditions.
If necessary, replace the end fitting. Very small particles, ion precipitation from
sample/column ionic interaction (i.e., calcium carbonate), and strongly retained
chemical contaminants which reach the bed can often be removed from the
plugged outlet fit by a more extensive cleanup. Inlet and outlet end fittings should
be removed one at a time according to the procedure given in Section 6.4.
Substitute step 4 of the procedure in Section 6.4 with sonication of the end fitting
in pure water. Note that this is a procedure of last resort, and should only be used
if all other attempts at repairing the column have failed and nothing else can be
done to rejuvenate the column.
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