Bio-Rad AG® MP-50 Cation Exchange Resins - Manual (Page 9)

7. The actual flow rate that is used will depend upon the
application, the resin, and the column cross section.
To obtain flow rates for any given size column,
multiply the suggested flow rates in Table 6 by the
column cross-sectional area. Table 6 gives typical
flow rates of analytical grade resins.
8. If a cation-free solution is the goal, collect the effluent.
If the concentrated cations are of interest, allow all of
the sample to pass through the column, then elute the
metals with a solution containing a counterion of
higher selectivity than the bound cation.
Table 6. Suggested Flow Rates for Ion
Exchange Resin Columns
Flow Rates
Application cm/min
Removing trace ions 5-10
Separations with very few components 1-3
Separations of multi-component samples 0.3-1.0
Using high resolution resins
with small particle size
0.1-0.2
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4. Slurry and pour the resin into the column. Equilibrate
the resin in the initial buffer using 3 bed volumes of
buffer. Poorly equilibrated resin will not give
reproducible results. Alternatively, equilibration can
be done by the batch technique, prior to pouring the
column. First, convert the resin to the appropriate
form, then suspend it in the starting buffer. Check the
pH with a pH meter while stirring continuously.
Adjust the pH by adding acid or base dropwise to the
buffer until the desired pH is obtained. Then transfer
the resin to the column, and pass 1 bed volume of the
starting buffer through the column.
5. Add the initial buffer and allow excess buffer to pass
through the column, leaving enough buffer to just
cover the top of the resin bed.
6. Apply the sample dropwise to the top of the column
without disturbing the resin bed. Drain the sample
into the top of the bed and apply several small
portions of starting eluant, being very careful to rinse
down the sides of the column and to avoid stirring up
the bed. Drain each portion to the level of the resin
bed before the next portion is added. Never allow the
liquid level to drain below the top of the resin bed.
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LIT203B 6/17/98 12:00 PM Page 12