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Handbook of Size Exclusion Chromatography and Related ...

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Figure 6 Overlay <strong>of</strong> GPC chromatograms <strong>of</strong> commercial grades <strong>of</strong> PVP using<br />

Ultrahydrogel linear column <strong>and</strong> 80:20 (vol/vol) water–MeOH with 0.1 M LiNO 3.<br />

4 MOLECULAR WEIGHTS AND MOLECULAR WEIGHT<br />

DISTRIBUTIONS OF VP-BASED COPOLYMERS BY SEC<br />

4.1 Nonionic Copolymers: Copolymers <strong>of</strong> Vinyl Pyrrolidone<br />

<strong>and</strong> Vinyl Acetate (VA) <strong>and</strong> Terpolymer <strong>of</strong> Vinyl<br />

Pyrrolidone, Dimethylaminoethyl Methacrylate<br />

(DMAEMA), <strong>and</strong> Vinyl Caprolactum (VC)<br />

Wu et al. reported in 1991 (6) the SEC <strong>of</strong> PVP/VA copolymers <strong>and</strong> PVP/<br />

DMAEMA/VC terpolymer in both aqueous <strong>and</strong> nonaqueous systems. For the<br />

aqueous system the column set consisted <strong>of</strong> four Waters Ultrahydrogel columns <strong>of</strong><br />

pore sizes 120, 500, 1000, <strong>and</strong> 2000 A ˚ , <strong>and</strong> the mobile phase was 1:1 water–<br />

methanol (vol/vol) with 0.1 M LiNO3. Aqueous mobile phases with no organic<br />

modifiers, such as methanol, cannot be used because <strong>of</strong> the poor solubility <strong>of</strong> some<br />

<strong>of</strong> the nonionic copolymers in pure water <strong>and</strong> the adsorption <strong>of</strong> the copolymers by<br />

the columns. For the nonaqueous system, the column sets were Shodex KD-80M<br />

© 2004 by Marcel Dekker, Inc.

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