Bio-Rad Bio-Beads S-X Media - Manual (Page 6)

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the Bio-Beads S-X beads will not swell, and the pore size
will be minimal. The chosen solvent should be the one used
for the separation, and the same as the solvent in which the
sample is dissolved.
The solvents should be of highest quality available, and
preferably redistilled if non-volatile matter is present in
them. Some solvents, e.g. tetrahydrofuran, develop perox-
ides on standing in contact with air. Solvents should gener-
ally be degassed prior to use and protected from
atmospheric contamination, to prevent later outgassing dur-
ing the chromatographic run.
Bio-Beads S-X1 beads will swell considerably, and
should be placed in at least six times the resin weight of sol-
vent (w/w). The higher crosslinked resins will not swell as
much, so they will not require as much elution solvent. The
swelling should always be done in the presence of excess
solvent to prevent the resin from drawing up all the solvent,
and possibly not swelling fully. The higher crosslinked
resins will require more time to become fully swollen.
Bio-Beads S-X12 and S-X8 beads may require swelling
overnight, whereas the lower crosslinked resins will be fully
swollen in a few hours. Complete swelling is necessary to
prevent swelling after packing, which could break the col-
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