Bio-Rad AG® MP-50 Cation Exchange Resins User Manual
Page 6
Large mesh material (20-50 and 50-100 mesh) is
used primarily for large preparative applications and
batch operations where the resin and sample are slurried
together. Medium mesh resin (100-200 mesh) is used
primarily in column chromatography for analytical and
laboratory scale preparative applications. Fine mesh
material (200-400 and minus 400 mesh) is used for high
resolution analytical separations.
Table 4. Wet Mesh and Equivalent Micron
Diameters
Wet Mesh
(U.S. Standard)
16
20
40
50
80
100 140 200 270 325 400
µm Diameter
(1 µm=0.001msm) 1,180 850 425 300 180
150 106
75
53 45
38
Section 4
Resin Conversion
Table 5 outlines common techniques for converting
ion exchange resins from one ionic form to another.
Resin conversion is most efficiently carried out in the
column mode. However, when choosing a column,
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Table 3. Relative Selectivity of Various
Counterions
Relative Selectivity
Relative Selectivity
Counterion
for AG 50W-X8 Resin
Counterion for AG 50W-X8 Resin
H
+
1.0
Fe
2+
2.55
Li
+
0.85
Zn
2+
2.7
Na
+
1.5
Co
2+
2.8
NH
4
+
1.95
Cu
2+
2.9
K
+
2.5
Cd
2+
2.95
Rb
+
2.6
Ni
2+
3.0
Cs
+
2.7
Ca
2+
3.9
Cu
+
5.3
Sr
2+
4.95
Ag
+
7.6
Hg
2+
7.2
Mn
2+
2.35
Pb
2+
7.5
Mg
2+
2.5
Ba
2+
8.7
The AG 50 resins are available in several particle
size ranges. The flow rate in a chromatographic column
increases with increasing particle size. However, the
attainable resolution increases with decreasing particle
size and narrower size distribution ranges. Particle size is
given either in mesh size or micron size. The larger the
mesh size number, the smaller the particle size. Table 4
shows wet mesh and equivalent micron diameters.
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LIT203B 6/17/98 12:00 PM Page 6