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Handbook of Size Exclusion Chromatography and Related ...

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Figure 1 <strong>Size</strong> exclusion chromatograms <strong>of</strong> PAM, HYPAM, <strong>and</strong> AM/DMDAAC<br />

copolymer (raw data).<br />

AM/DMDAAC copolymer is afunction <strong>of</strong> MW.This phenomenon is caused by<br />

the different copolymer reactivity ratios <strong>of</strong> acrylamide <strong>and</strong> DMDAAC<br />

(rAM ¼2.36, rDMDAAC ¼0.046) monomers. Again, the narrow line shape <strong>of</strong><br />

thehigh MWportion may bedue tothe poorseparation capability<strong>of</strong>thecolumns<br />

at the upper MW end (about 5 10 6 g/mole). Langhorst <strong>and</strong> co-workers (53)<br />

statedthatthecombination<strong>of</strong>hydrodynamicchromatography(HDC)<strong>and</strong>LALLS<br />

detectioncanbeappliedtodetermineMW<strong>and</strong>MWD<strong>of</strong>partiallyhydrolysedPAM<br />

up to M w¼9 10 6 g=mole.<br />

Figure 3 shows two chromatograms <strong>of</strong> low MW 90/10 wt% AM/<br />

DMDAAC copolymer samples with solvent peaks <strong>of</strong> different polarity.The low<br />

MW tail <strong>of</strong> the chromatogram overlaps with the salt peak. Therefore, the final<br />

processing time is difficult to determine <strong>and</strong> the M w, M n, <strong>and</strong> M w=M nvalues<br />

© 2004 by Marcel Dekker, Inc.

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