Handbook of Size Exclusion Chromatography and Related ...

number of branching points); crosslinks; oxidation status; compatibility
structures; packing density.
. Dimension [md; Eq. (1)]: molecular weight/degree of polymerization/
excluded volume; transition states between geometric molecular
dimensions and coherence lengths of supermolecular structures.
. Interactive properties [ip; Eq. (1)]: water content; aggregation/
association; supermolecular dimensions (gel-formation); visco-elastic
qualities; stress management.
Ve ¼ ip md mc
where Ve ¼ excluded volume, ip ¼ interactive potential, md ¼ molecular
dimension, and mc ¼ molecular conformation. However, although variations of
md, mc, and ip already provide countless options, diversity is increased even more
by distributions of these features. In particular, starch glucans are a superimposed
heterogeneous mix of regular and irregular modules:
. Highly symmetrical helices (multiple helices), primarily by lcb-glucans,
. Irregular “fractal” structures, primarily by scb-glucans,
. Compact and internally H-bond stabilized structures, predominantly by
scb-glucans (crystallinity),
. Less compact “amorphous” domains with pronounced re-organization
capability, predominantly by lcb-glucans,
which may easily be customized either with respect to mass [Eq. (2)] or molar [Eq.
(3)] fractions of components for the major native purpose: to support optimum
energy management.
m VeD ¼ ipD m mdD mcD
where m V eD ¼ mass fractions of excluded volumes distribution, ipD ¼
distribution of interactive potentials, m mdD ¼ mass fraction of molecular
dimensions distribution, and mcD ¼ distribution of molecular conformation.
n VeD ¼ ipD n mdD mcD
where n V eD ¼ molar fractions of excluded volumes distribution, ipD ¼
distribution of interactive potentials, n mdD ¼ molar fraction of molecular
dimensions distribution, and mcD ¼ distribution of molecular conformation.
In fact, the separation criterion in SEC is excluded volume (Ve: excluded
volume). Thus, application of SEC on starch glucans should provide basic
information about excluded volume heterogeneity (VeD: excluded volume
distribution). Combining SEC with several appropriate on-line detection
© 2004 by Marcel Dekker, Inc.
(1)
(2)
(3)