Bio-Rad Media Sampler Pack - Manual (Page 7)

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Section 6
Operation and Maintenance
UNOsphere media were designed to achieve the highest productivity (grams of
drug per operational hour per liter of media) possible. UNOsphere media should be
run at the highest linear velocities and loading capacities allowed by the column
and chromatography system. A linear flow rate of 600 cm/hr and a 20 cm bed is a
recommended starting point. The purification may be optimized by changing the
pH or flow rate, changing the ionic strength of the elution buffer, modifying the
gradient profile, or experimenting with different buffer salts.
All buffers commonly used for anion or cation exchange chromatography can be
used with the respective UNOsphere ion exchange media (see Table 2). The
chemical stability and broad operating pH range of these ion exchangers allow the
use of a variety of buffers. The use of buffering ions that have the same charge as
the functional group on the ion exchanger (e.g., phosphate with a cation exchanger
and Tris with an anion exchanger) will produce the best results.
0
5
10
15
20
0 200 400 600 800 1,000 1,200
Velocity cm/h
Pressure psi
Fig. 2. UNOsphere Q and S pressure/flow chart for a 11 x 200 mm column using
deionized water as eluent. Note: Backpressure may vary for different column
hardware.
Pr
essur
e, psi
Velocity, cm/hr
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