28.02.2013 Views

Handbook of Size Exclusion Chromatography and Related ...

Handbook of Size Exclusion Chromatography and Related ...

Handbook of Size Exclusion Chromatography and Related ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

plus Ultrahydrogel 120 A ˚ ,Shodex KD-80M plus PLgel 100 A ˚ ,<strong>and</strong> PLgel 10 4 A ˚<br />

plus 500 A ˚ ,<strong>and</strong> the mobile phase was DMF with 0.1 MLiNO 3.<br />

For the nonaqueous systems, the peak shapes are very similar for all three<br />

column sets; the Shodex KD-80M plus Ultrahydrogel 120 A ˚ provides<br />

slightly better separation <strong>of</strong> the solvent peak <strong>and</strong> the low-molecular-weight end<br />

<strong>of</strong> the polymer peak. However, the aqueous system showed the best separation at<br />

the low-molecular-weight end, as shown in Figs 8<strong>and</strong> 9. The weight-average<br />

molecularweights<strong>and</strong>intrinsicviscositiesdeterminedinaqueous<strong>and</strong>nonaqueous<br />

systems (Shodex KD-80M plus Ultrahydrogel 120 A ˚ )are shown in Table 7.<br />

A100% recovery was achieved in both aqueous <strong>and</strong> nonaqueous systems for<br />

PVP/VAin SEC.<br />

4.2 Anionic Copolymers: Copolymers <strong>of</strong> Vinyl Pyrrolidone<br />

<strong>and</strong> Acrylic Acid (AA)<br />

Even though this copolymer is soluble in the water–methanol (50:50, vol/vol)<br />

mobile phase with 0.1 Mlithium nitrate, no recovery <strong>of</strong> the copolymer can be<br />

obtained in SEC with the Ultrahydrogel columns in this mobile phase. Wu et al.<br />

reportedin1991(6)theSEC<strong>of</strong>PVP/AAusinga0.1 MpH 9Trisbufferwith0.2 M<br />

LiNO3 as the mobile phase <strong>and</strong> the Ultrahydrogel 120, 500, 1000, <strong>and</strong> 2000 A ˚<br />

column set. The PVP/AA samples were first dissolved in 0.25 NNaOH (1%,<br />

Figure 8 SECtraces<strong>of</strong>PVP/VA,Iseries,usingtheShodexKD-80M<strong>and</strong>Ultrahydrogel<br />

120A ˚ columns with DMF solvent. (From Ref. 6.)<br />

© 2004 by Marcel Dekker, Inc.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!