Owner manual

Table 2. Guide to Analytical Grade Anion
Exchange Resins
Resistance
Resin Active Order of Thermal Solvent to Oxidizing
Type Group Selectivity Stability Stability Agents
AG 1
R-CH
2
N
+
>phenolate OH
-
form, Very good Slow
and (CH
3
)
3
>HSO
4
>ClO
3
fair to 50 °C; solution
AG MP-1 >NO
3
>Br> Cl
-
and other in hot 15%
Resins CN>HSO
3
> forms, good HNO
3
or
NO
2
>Cl> to 150 °C conc. H
2
O
2
HCO
3
>IO
3
>
H
2
COO>Ac>
OH>F
AG 2 R-CH
2
N
+
phenolate>I OH
-
form, Very good Slow
Resin (CH
3
)
2
>HSO
4
>ClO
3
to 30 °C; Cl
-
solution
C
2
H
4
OH >NO
3
>Br> forms, good in hot 15%
CN>HSO
3
> to 150 °C HNO
3
or
NO
2
>Cl>OH conc. H
2
O
2
>IO
3
>H
2
COO
>Ac>F
Section 3
Mechanism
In an ion exchange procedure, the counterions on
the resin are replaced by sample ions that have the same
charge. With anion exchange resins such as AG 1 and
5
Each AG 1 resin is supplied in the chloride form.
Selected resins are available in the acetate, formate, and
hydroxide form. These ionic forms may be considered
more activated forms than the chloride form, as may be
deduced from the order of selectivity information given
in Tables 2 and 3. AG 1 resins purchased in the more
active forms may be converted to any other form. The
chloride ion, because of its higher selectivity for the
resin, is relatively difficult to replace with formate,
acetate, hydroxide, or fluoride. Thus, if various ionic
forms are to be used, the formate or acetate forms pro-
vide flexibility and convenience (see Table 3). Formate
and acetate forms may be used to separate most low
molecular weight biological compounds, such as
nucleotides, hormones, peptides, and carboxylic acids.
AG MP-1 resin is the macroporous equivalent of AG 1
resin. Its effective surface area approximates 23 square
meters per dry gram, 20% porosity.
The physical properties of the resins are listed in
Table 2. The anion exchange resins are thermally stable
and resistant to solvents (alcohols, hydrocarbons, etc.),
reducing agents, and oxidizing agents.
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LIT212C 6/17/98 12:25 PM Page 4