Bio-Rad AG® MP-50 Cation Exchange Resins - Manual (Page 4)

Table 1. Approximate Molecular Weight Exclusion
Limits for Ion Exchange Resins in Water
Percent Approximate MW Exclusion Limit
Crosslinking for Globular Molecules
2% 2,700
4% 1,400
8% 1,000
10% 800
12% 400
AG MP-50 resin is the macroporous equivalent of
AG 50W resin. Its effective surface area approximates
35 square meters per dry gram, or 30-35% porosity.
The physical properties of the resins are listed in
Table 2. The cation exchange resins are thermally stable
and resistant to solvents (alcohols, hydrocarbons, etc.),
reducing agents, and oxidizing agents.
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a styrene divinylbenzene copolymer lattice. The amount
of resin crosslinking determines the bead pore size. A
resin with a lower crosslinkage has a more open structure
permeable to higher molecular weight substances than a
highly crosslinked resin. It also has a lower physical
resistance to shrinking and swelling, so that it absorbs
more water and swells to a larger wet diameter than a
highly crosslinked resin of equivalent dry diameter. For
example, typical applications of AG 50W-X2 2%
crosslinked resin and AG 50W-X4 4% crosslinked resin
include separation or concentration of peptides,
nucleotides, and amino acids. In high percentage
crosslinkage, (AG 50W-X8 8% resin, AG-50W-X12
12% resin, and AG 50W-X16 16% resin) applications
include separation of small peptides and amino acids,
removal of cations, and metal separations. Table 1 shows
the approximate molecular weight exclusion limits in
water for resins of various crosslinkages. All AG 50W
resins are supplied in the hydrogen form, and selected
AG 50W-X8 resins are available in sodium and
ammonium forms.
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LIT203B 6/17/98 12:00 PM Page 2