Bio-Rad Chelex® 100 Resin - Manual (Page 5)

Instructions for Use
Chelex resins may be used with either a batch
method or a column method.
Batch Method
The batch method is the addition of resin directly
into the sample followed by stirring.
1. Weigh out about 5 grams of resin for every
100 ml of sample. For larger scale applications or
when a more exact amount of resin is needed, use
the capacity guidelines given below to calculate
the resin volume for the specific sample metal
concentration.
2. Add resin to the sample and stir or shake (gently)
for 1 hour.
3. Filter or decant the sample from the resin.
Column Method
The column method involves pouring a column
with the Chelex resin and passing the sample through
to achieve the separation. Although large mesh mate-
rial (50-100 mesh) allows rapid flow rates and the
ability to process large volumes of solution, resolution
may be sacrificed. On the other hand, small mesh
material (200-400 mesh) can achieve very high resolu-
tion and analytical results, but will require longer pro-
cess time due to the slow flow rate.
1. Calculate the amount of resin required based on
the expected metal concentration. If the metal
concentration is unknown, begin with 5 grams of
resin for 100 ml of sample, and then optimize the
volumes after obtaining the results.
2. Prepare a buffer with a pH and ionic concentration
that will allow the metal to be ion-exchanged easily
onto the column. Use the information from Table 1,
and the selectivity comparisons of different pH
solutions mentioned above, to optimize the buffer.
For unknown solutions, use deionized water.
3. Slurry the resin in the buffer, and pour the col-
umn. Allow several bed volumes to pass through
the column to insure a well packed bed.
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LIT200B 6/17/98 11:49 AM Page 6