Bio-Rad Chelex® 100 Resin - Manual (Page 8)

5. The wet capacity of Chelex resin is 0.40 meq/ml.
Knowing this, the volume of resin needed can be
calculated.
6. Convert the volume in step 5 to weight. The den-
sity of Chelex resin is 0.65 g/ml.
Example: 6.58 ml x 0.65 g/ml = 4.3 grams
pH Stability
Chelex resin is stable over the entire pH range and
functionally active from pH 2-14.
Flow Rates
If a tightly held cation is to be isolated from a solu-
tion of weakly held cations, a flow rate in excess of 20
cm/min can often be used. Separations between similar
species and efficient regeneration and conversion
require lower flow rates, usually less than 4 cm/min.
Example: = 6.58 ml
2.63 meq
0.4 meq/ml
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3. Calculate the total weight of the metals. Usually,
metals are measured in parts per million (ppm). In
aqueous solutions, ppm can be assumed to be
mg/liter.
Example: Cu +2 = 3 ppm
Cd +2 = 5 ppm
Cr +3 = 2 ppm
10 ppm or 10 mg/liter
10 mg/liter x 10 liters = 100 mg
4. Convert the weight determined in step 3 to equiv-
alence. Equivalence = weight in grams/equivalent
weight, where equivalent weight = molecular
weight/average valence.
Example: = 2.63 meq
100 mg
76 g/mol
2 eq/mol
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LIT200B 6/17/98 11:49 AM Page 12