Bio-rad Prepacked Gravity Flow Columns for Ion Exchange Manuel d'utilisateur télécharger pdf (Page 6)

The ion exchange capacity, usually

expressed as meq/ml of resin, is equivalent to

the number of ion exchange sites per unit vol-

ume of resin. The following examples shows

the calculated volume of 1 N sodium hydrox-

ide that would be required to convert the 2 ml

of resin in a prefilled AG 50W-X8 (H+) Poly-

Prep column from the hydrogen form to the

sodium form. In general, it is recommended to

use only 70-80% of the theoretical capacity of

an ion exchange resin.

1 N = 1 equivalent/liter = 1 milliequivalent/milli-

liter (1 meq/ml)

AG 50W-X8 ion exchange capacity = 1.7 meq

1.7 meq/X ml = 1 N

1.7 meq/1 N = X ml

X = 1.7 ml

Therefore, 1.7 mls of 1 N NaOH required

to convert the AG 50W-X8 resin to the sodium

form.

Section 5

Flow Rate Characteristics

The flow rate of an ion exchange resin is

primarily determined by the particle size of the

resin. Using gravity flow, the expected flow

rate for 100-200 mesh resin in prefilled Poly-

Prep columns is approximately 4-6 ml/minute.

The flow rate for 200-400 mesh resin is

approximately 1.5 ml/minute.

Bio-Rex 70 resin has slower flow rate than

AG or Chelex resins. Bio-Rex 70 100-200 mesh

resin flows at approximately 1.0 ml/minute.

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Bio-rad Prepacked Gravity Flow Columns for Ion Exchange Manuel d'utilisateur Page 6