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Handbook of Size Exclusion Chromatography and Related ...

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Figure 13 Gradient reversed-phase HPLC <strong>of</strong> lysozyme showing two conformers in<br />

both the UV <strong>and</strong> light-scattering tracings. Light scattering was measured using an<br />

HPLC fluorimeter at 908. (From Ref. 211, with permission from Elsevier Science<br />

Publishers.)<br />

5 SPECIAL APPLICATIONS<br />

Cotts (105) showed that SEC-LALLS could be combined with universal<br />

calibration to determine the intrinsic viscosity at each elution volume increment.<br />

As in SEC-viscometry with universal calibration, the accuracy <strong>of</strong> the calculated<br />

values depends upon the chromatograms being corrected for axial dispersion. In<br />

addition, the Mark–Houwink coefficients can be determined from a plot <strong>of</strong><br />

molecular weight <strong>and</strong> intrinsic viscosity at each elution volume for the whole<br />

molecular weight distribution. However, it was noted that the values obtained were<br />

also sensitive to axial dispersion. Another source <strong>of</strong> error arises from the<br />

polydispersity in individual elution volume increments, because universal calibration<br />

requires that the number-average molecular weight be used to calculate<br />

intrinsic viscosity.<br />

© 2004 by Marcel Dekker, Inc.

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