The maximum concentration specification for the Zetasizer Nano S or ZS instrument to measure size is 40% w/v. This article includes details of the experimental procedures and results achieved from measurements of a nominally 100 nm silica suspension at a concentration of 40% w/v to demonstrate this maximum concentration limit.
Experiment
Materials
- DTS0012 disposable sizing cuvettes
- 40% w/v colloidal silica suspension with a nominal size of 100 nm
Method
The 40% w/v silica suspension was first placed into a DTS0012 disposable sizing cuvette, taking care to make sure that air bubbles were not present. The measurements were then taken at a temperature of 25 °C.
Results
Figure 1 illustrates the intensity size distributions obtained from 5 repeat measurements of a nominally 100 nm silica suspension at a concentration of 40% w/v, representing the repeatability of measurement at this concentration.
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Figure 1. Intensity size distributions obtained from 5 repeat measurements of a nominally 100 nm silica suspension at a concentration of 40%.
Figure 2 is an overplot of the correlation functions of these measurements, illustrating an exceptional repeatability and an intercept of 0.77 signifying a good signal and a low probability of multiple scattering which would have an effect on the size measured.
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Figure 2. Correlation functions obtained from 5 repeat measurements of a nominally 100 nm silica suspension at a concentration of 40%.
Conclusions
The results reported in this article prove that the maximum concentration specification for size measurements on the Zetasizer Nano S or ZS instrument is 40% w/v.

This information has been sourced, reviewed and adapted from materials provided by Micromeritics Instrument Corporation.
For more information on this source, please visit Micromeritics Instrument Corporation.