Malvern Zetasizer Nano Series, User Manual

Page: 199 / 256

The diagram below shows how the Molecular weight and 2
nd
Virial Coefficient
are derived from the Debye plot.
As only one measurement angle is used in this case, a plot of K/CR
q
versus C
should give a straight line whose intercept at zero concentration will be 1/M and
whose gradient will be A
2
.
C H A P T E R 1 4
Z e t a s i z e r N a n o S e r i e s
P a g e 1 4 . 5
C - concentration
Samples
of varying
concentration
Intercept point
Standard sample
i.e. pure solvent
Gradient
k/CR
-
Intensity
of
scattered
light
q
1
1
2
2
3
3
4
4
0
ILL
6745