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Handbook of Size Exclusion Chromatography and Related ...

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where ais the exponent <strong>of</strong> the Mark–Houwink equation,<br />

[h] ¼KM a<br />

2.2 Experimental TDS Work for PVA<br />

Figure 1 is a schematic <strong>of</strong> an experimental setup used by this author for<br />

aqueous SEC with aTDS interface. This system also employs athree-angle<br />

MALLSdetectorforthesimultaneouscapture<strong>of</strong>datafrombothTDS<strong>and</strong>MALLS<br />

detection. Table 1 summarizes the specific conditions used. The MALLS<br />

photometer (Mini-Dawn from Wyatt Technology, Santa Barbara, California,<br />

U.S.A.) is configured in series between the SEC instrument <strong>and</strong> aDRI detector<br />

(Waters Corporation Model 410, Milford, Massachusetts, U.S.A.). The TDS<br />

detector (Viscotek Model T60A, Houston, Texas, U.S.A.) is configured in a<br />

parallelarrangementwiththeDRIdetectorsothattheflowissplitevenlybetween<br />

the two detectors. The aqueous mobile phase <strong>of</strong> 0.05 M sodium nitrate was<br />

prefilteredthrougha0.45mmembrane(Gelman)toremoveanyparticulates.Data<br />

acquisition <strong>and</strong> processing were carried out using ASTRAversion 4.72 s<strong>of</strong>tware<br />

for MALLS <strong>and</strong> Viscotek TriSEC Version 3.0 s<strong>of</strong>tware for TDS.<br />

The<strong>of</strong>fsetvolumebetweentheRI<strong>and</strong>TDSdetectorwasdeterminedusinga<br />

poly(ethylene glycol) st<strong>and</strong>ard <strong>of</strong> 22,800 molecular weight. The <strong>of</strong>fset volume<br />

Figure 1 TDS/MALLS experimental setup. (Reprinted from American Laboratory,<br />

Vol. 35, 1, Copyright 2003 by International Scientific Communications, Inc.)<br />

© 2004 by Marcel Dekker, Inc.

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