A new application note, freely available on the Malvern
Instruments' website, describes how the new ZEN1010 high concentration zeta
potential cell for the company's market-leading Zetasizer Nano particle characterization
system, overcomes a major hurdle in measuring the zeta potential of high concentration
samples.
Taking the notoriously difficult to measure titanium dioxide as an example,
the authors describe experimental work that demonstrates accurate and reliable
zeta potential measurement of concentrated, turbid suspensions. This ability
to measure the zeta potential of more concentrated samples than has previously
been possible is thanks to the reduced optical path length of the new ZEN1010
cell, and has applications for a very wide range of materials. The application
note can be downloaded at www.malvern.com/titaniumdioxide
Because of its high refractive index, titanium dioxide is widely used as a
pigment in products such as paints, coatings, paper, food and cosmetics. To
perform optimally, the titanium dioxide particles must be properly dispersed
and maintained in suspension, and a key parameter used to study dispersion behaviour
is zeta potential. This parameter is measured using the technique of laser Doppler
electrophoresis, which normally requires samples to be optically clear. The
new ZEN1010 cell, however, features an optical path of reduced length, which
compensates for the issues of reduced light scattering detection experienced
with standard cells when measuring high-concentration samples.
Although it is used in the same way as a standard cell on the Zetasizer Nano,
the ZEN1010 allows robust zeta potential measurements in highly concentrated
samples. By requiring less sample dilution, it more closely preserves the pH
and chemical structure of the sample, for more directly relevant zeta potential
measurements. This is especially important for many colloidal materials, where
measuring the sample in its native state avoids the need for the often complicated
centrifugation and dilution procedures needed to maintain sample integrity.
Download this and other application notes on the Malvern website at www.malvern.com
Malvern, Malvern Instruments and Zetasizer are registered trademarks of Malvern
Instruments Ltd