Bio-Rad Bio-Rex 5 Anion Exchange Resins User Manual

AG®3, AG 4, and Bio-Rex®5

Anion Exchange Resin

Instruction Manual

Bio-Rad Laboratories, 2000 Alfred Nobel Dr., Hercules, CA 94547

LIT207 Rev B

AG 3, AG 4, and Bio-Rex 5 Resin
Weakly Basic and Intermediate Basic
Anion Exchange Resin Instructions

Introduction

AG 3-X4 and AG 4-X4 resins are weakly basic
anion exchangers. These resins can exchange anions,
such as organic acids, with weak interactions, allowing
easy elution and regeneration. They will also adsorb
mineral acids, such as hydrochloric acid and perchloric
acid, to yield a neutralized solution. Bio-Rex 5 resin is an
intermediate basic anion exchanger, which also
exchanges anions, such as iodide, bromide, and chloride,
with weak interactions, allowing easy elution and
regeneration.

Technical Description

AG 3-X4, AG 4-X4, and Bio-Rex 5 resins are all
analytical grade purity. They have been exhaustively
sized, purified, and converted to make them suitable for
accurate, reproducible analytical techniques. AG 4-X4
resin is also available in Biotechnology Grade,
Analytical Garde resin which has been further processed

1

and is certified to contain less than 100 microorganisms
per gram of resin.

AG 3-X4 resin and AG 4-X4 resin are both 4%
crosslinked and have a tertiary amino functional group.
The resins differ in their backbone resin matrix material.
AG 3-X4 resin has a styrene-divinylbenzene copolymer
lattice matrix, and AG 4-X4 resin has an acrylic matrix.
These two matrices differ in their physical and
mechanical strength, and in their inherent hydrophilic
nature. The styrene-divinylbenzene matrix (AG 3-X4
resin) is very strong mechanically, but is hydrophobic,
which can cause adsorption of large organic molecules or
proteins. The acrylic matrix (AG 4-X4 resin) is softer,
and therefore sensitive to crushing from excess flow rates
or very large column sizes. This material is hydrophilic
and is suitable for use with high molecular weight
organic compounds, proteins, and carbohydrates.

Bio-Rex 5 intermediate base resin contains primarily
tertiary, but also some quaternary, amines on a styrene­divinylbenzene lattice. Bio-Rex 5 resin can be used to
separate organic acids from neutral sugars. When the
resin is regenerated with base, the quaternary ammonium

2

groups will be in the hydroxide form, while the tertiary
amine groups will be in the free base form.

The physical properties of the resins are listed in
Table 1. These resins are thermally stable and resistant to
solvents (alcohols, hydrocarbons, etc).

Table 1. Summary of Properties

Resin Type Active Group Selectivity Stability Stability

Bio-Rex 5 R-N(CH
intermediate HSO
base NO
anion HSO
exchanger >HCO

AG 4-X4 R-CH
AG 3-X4 CrO
weakly basic tartaric>oxalic
anion >H
exchangers H

N+(CH3)2HSO3>HCit> Good to Good

2

Order of Thermal Solvent

I>phenolate> Good to Good

3)2

>CIO3> 60 °C

4

>Br>CN>

3

>NO2>CI

3

>IO3>

3

COO>HC>

H

2

OH>F

3>H2SO4

>

3PO4

AsO4>HNO

4

>HI>HBr>HCl
>HF>HCOO>
HAc>H2CO

3

> 60 °C

3

Mechanism

Both AG 3-X4 and AG 4-X4 resin are available in
the free base form. Here the functional group is neutral,
and is not charged. When a mineral acid is passed over

3