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Handbook of Size Exclusion Chromatography and Related ...

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Figure 4 PEOcalibration<strong>of</strong>Ultrahydrogellinearcolumnin20:80(vol/vol)methanol–<br />

water with 0.1 M LiNO3.<br />

the20:80methanol–watermixturetogeneratelargerporesizes<strong>and</strong>volumesthan<br />

in the 50:50 methanol–water mixture. As discussed later, the larger porevolume<br />

in the 20:80 mixture may provide better separation at the high-molecular-weight<br />

end.<br />

Overlays <strong>of</strong> SEC chromatograms <strong>of</strong> five commercial grades <strong>of</strong> PVP using<br />

the Shodex KB-80M linear column with amobile phase <strong>of</strong> 20:80 (vol/vol)<br />

MeOH/H2Owith0.1 MLiNO3<strong>and</strong>theUltrahydrogellinearcolumnwithamobile<br />

phase<strong>of</strong>either20:80(vol/vol)MeOH/H2Owith0.1 MLiNO3or50:50(vol/vol)<br />

MeOH/H2Owith0.1 MLiNO3areshowninFigs5,6,<strong>and</strong>7.Adequateseparation<br />

<strong>of</strong> all commercial grades <strong>of</strong> PVP can be obtained from all three systems.<br />

Table 5 Retention Times <strong>of</strong> PEO Using Ultrahydrogel Linear Column in Different 0.1 M<br />

Lithium Nitrate Mobile Phases<br />

PEO (AMU) 20:80 Water/MeOH 50:50 Water/MeOH<br />

885,000 13.00 12.88<br />

570,000 13.47 13.33<br />

270,000 14.08 13.92<br />

160,000 14.53 14.33<br />

85,000 15.15 14.93<br />

45,000 15.92 15.73<br />

21,000 16.67 16.40<br />

10,750 17.33 17.17<br />

4,250 18.08 17.97<br />

© 2004 by Marcel Dekker, Inc.

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