Handbook of Size Exclusion Chromatography and Related ...

an Ubbelohde-viscometer for concentration series at increasing times of the
dissolution process. Extrapolation of reduced viscosity values for each
concentration series [Eq. (23)] to c!0yields intrinsic viscosity [Eq. (24)] for
investigated states of dissolution (Fig. 26).
h red ¼ tsolution tsolvent
tsolventc
(23)
[h] ¼h red(c !0) (24)
Obviously,intrinsicviscosity([h])and,thus,excludedvolume(Ve),decreasesand
overlapping concentration (c*) increases with increasing time: an indication that
matcheswithdegradationofhugeglucanmoleculesaswellaswiththepresenceof
supermolecular glucan aggregates that disintegrate by the continuous dissolution
process. However, asignificant difference between data from bulk investigations
(Fig.26) and data from component analysis (Fig.22a) isobservedfrom the initial
state: in bulk solutions supermolecular glucan aggregates shift results for intrinsic
viscosity and overlapping conentration more than sixfold (approx.).
Figure 26 Wheat glucans. Intrinsic viscosity [h] of the bulk solution for increasing
periods of dissolution process.
© 2004 by Marcel Dekker, Inc.