Chapter 6
Advanced protein features
Page 6-8
MAN 0487
Interpreting the results
The record view
As part of each group measurement, the count rate is measured and a rolling
average taken as the measurement proceeds.
Aggregates are, generally, characterised by a much larger particle size than the
native protein and if any aggregates are present then large changes in the measured
count rate in each group will be observed. This will happen even if there are only
tiny fractions of aggregates present with respect to the fraction of protein.
Therefore once all of the measurement groups have been recorded, any groups that
have a significantly higher count rate than the average will be removed from the
averaging procedure.
The mobility over the remaining groups is then calculated and reported into the
record view as a
zeta
potential child record of the
protein mobility
parent record.
Note
The
Expert
system will warn the user if
less
than
ten
groups are left once
aggregated groups have been removed.
The average over un-aggregated groups will yield the mobility of only the
protein itself and not its aggregates, but the number of groups included in
the measurement will aid the user in assessing whether the measurement
of further aliquots is required.
The
pre
-mobility
size
records tell the user whether the sample is aggregated
prior to the mobility measurement.
If it is then the aggregates will, typically, scatter far more light than the native
protein and the aggregate mobility will dominate the result.
The
zeta
potential record is the measurement of the mobility of the protein
with the aggregated groups removed prior to calculating the final result and the
Expert
system will give advice on the quality of this measurement with regards
to field effects such as Joule heating.
Finally the
post
-mobility
size
measurement characterises the sample after the
mobility measurement.
This is especially important when the Diffusion Barrier is used, where the
sample may not have reached the electrodes; subsequently no electrode aggre-
gation should have occurred and the sample can be retrieved for further analy-
sis.
Summary of Contents for Zetasizer Nano Series
Page 2: ......
Page 3: ...Zetasizer Nano accessories guide MAN0487 Issue 1 1 April 2013...
Page 12: ...Chapter 1 Introduction and accessory range Page 1 6 MAN 0487...
Page 42: ...Chapter 2 General cells and cuvettes Page 2 30 MAN 0487...
Page 98: ...Chapter 5 Microrheology Page 5 20 MAN 0487...
Page 125: ......
