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

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Figure 20 Wheat glucans. Absolute molecular weight calibration achieved from<br />

scattering <strong>and</strong> mass detection at increasing periods <strong>of</strong> dissolution process; ! raw MWV<br />

[Eq. (17)].<br />

fraction, intrinsic viscosity pr<strong>of</strong>ile (eta int) may be obtained according to<br />

Eq. (19):<br />

eta int ¼<br />

eta spec<br />

mass ev inj mass<br />

Mean intrinsic víscosity (68) may be obtained according to Eq. (20):<br />

[h] av¼<br />

ð int stop<br />

int start<br />

eta intdVret<br />

(19)<br />

(20)<br />

Similar to light scattering, even viscosity preferentially senses high molecular<br />

<strong>and</strong> supermolecular components. However, if these components are present in<br />

below ppm-amounts—as is the case for starch glucan aggregates—their<br />

contribution to overall viscosity is negligible. Thus, viscosity detection <strong>of</strong> SEC<br />

separated starch glucans dominantly is structural viscosity <strong>of</strong> molecular<br />

dissolved glucans. The reciprocal <strong>of</strong> intrinsic viscosity is acrude measure <strong>of</strong><br />

overlapping concentration for these glucan molecules (Fig. 22).<br />

© 2004 by Marcel Dekker, Inc.

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

Saved successfully!

Ooh no, something went wrong!