Malvern Zetasizer Nano Series, Руководство пользователя

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The mean zeta potential that is calculated by this technique is therefore very
robust, as the measurement position in the cell is not critical.
However, as the velocity of the particles is sampled for such a short period of
time, information about the distribution is degraded. This is what is addressed by
M3, the PALS technique is used to determine the particle mobility in this part of
the sequence.
M3 measurement sequence
An M3 measurement is performed in the following manner:
.
A Fast field reversal measurement is performed at the cell centre. This
gives an accurate determination of the mean.
.
A Slow field reversal measurement is made. This gives better resolution,
but mobility values are shifted by the effect of electroosmosis.
.
The mean zeta potentials calculated from the FFR and SFR measurements
are subtracted to determine the electroosmotic flow. This value is used to
normalise the slow field reversal distribution.
.
The value for electroosmosis is used to calculate the zeta potential of the
cell wall.
Benefits of M3
Using M3 the entire Zeta potential measurement is simplified. It is no longer
necessary for the operator to select any system parameters for the measurement,
as the appropriate settings are calculated as part of the M3 sequence. With a
reduction in the number of measurement variables, both measurement
repeatability and accuracy is improved. Additionally, alignment is no longer an
issue as there are no concerns about the location of the stationary layer.
M3 is now combined with the PALS measurement.
C H A P T E R 1 5
Z e t a s i z e r N a n o S e r i e s
P a g e 1 5 . 9
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Stationary
Layer
Insignificant fluid flow
ILL
6754