Bio-Rad Bio-Rex 70 Cation Exchange Resins User Manual

Bio-Rex®Weakly Acidic

Cation Exchange Resin

Instruction Manual

Catalog Numbers
142-5822, 142-5832,
142-5842, 142-5852,
143-5832, 143-5852,

Table of Contents

Section 1 Introduction ..........................................1

Section 2 Technical Description...........................1

Section 3 Resin Equilibration ..............................6

Section 4 Resin Conversion..................................7

Section 5 Instructions for Use..............................7

5.1 Batch Method..................................................8

5.2 Column Method..............................................8

Section 6 Resin Regeneration.............................11

Section 7 Applications.........................................11

7.1 Protein, Peptide,

and Amino Acid Separations........................12

Section 8 Product Information...........................15

Section 1
Introduction

Bio-Rex 70 resin is a weakly acidic cation
exchanger. This resin is used for the purification and
fractionation of peptides, proteins, antibiotics, and other
cationic molecules.

Section 2
Technical Description

Bio-Rex 70 resin is available as both Analytical
Grade and Biotechnology Grade resin. The Analytical
Grade Bio-Rex 70 resin has been exhaustively sized,
purified, and converted to make it suitable for accurate,
reproducible analytical techniques. Biotechnology Grade
Bio-Rex 70 resin is an Analytical Grade resin which is
certified to contain less than 100 microorganisms per
gram of resin.

The resin contains carboxylic acid exchange groups
on a macroreticular acrylic polymer lattice. The high
porosity of the resin allows large protein molecules to
penetrate the pores and have access to the exchange sites
located throughout the matrix. In an ion exchange
procedure the counterions on the resin are replaced by

1

sample ions that have the same charge. On a cation
exchange resin such as Bio-Rex 70 resin, neutral
molecules and anions do not interact with the resin.

Normally Bio-Rex 70 resin is supplied in the sodium
form, but the resin can be converted from one ionic form
to another. Usually the resin is used in an ionic form with
a lower selectivity for the functional group than the
sample ions to be exchanged. The sample ions are then
exchanged when introduced, and can be eluted by
introducing an ion with higher affinity for the resin or a
high concentration of an ion with equivalent or lower
affinity. Table 1 shows the relative selectivity of various
monovalent and divalent counterions, as well as some
nominal properties of the Bio-Rex 70 resin.

Table 1. Properties of Bio-Rex 70 Resin

Wet density 0.6 ml/g (Na+and H+forms)

+

% moisture 65-74% (Na

form); 55-65%

(H+ form)

Swelling

1 ml (H+form); 1.7 ml (Na+ form)
Capacity 10 meq/dry g
Na+ form 0.5 meq/ml
H+ form 2.4 meq/ml
Pore volume 0.10 cc/cc
Pore size range 700-4,000 Å
Thermal stability Up to 100 °C
Normal operating

pH range 5 to 14
Order of selectivity

for monovalent ions H>>Ag>K>Na>Li
Order of selectivity

for divalent ions H>>Fe>Ba>Sr>Ca>Mg

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3