The minimum size specification (diameter) for the Zetasizer Nano S or ZS instrument is a peak mode of 0.6 nm with a minimum size of 0.3 nm. This article includes details of the experimental procedures and results obtained from measurements of sucrose solutions to demonstrate these minimum size specifications.
- De-ionized water
- Sucrose (food grade)
- Sizing cuvettes
- Whatman Anotop 10 syringe filters 20 nm pore-size
First, a 30% w/v solution of sucrose was prepared (30 g of sucrose made up to 100 g with deionized water) and the resultant sample was filtered through the 20 nm pore-size filter into a suitable cuvette. The measurements were then taken at 25 °C using a viscosity of 1.86 mPa.s.
Figure 1 illustrates the intensity size distributions obtained from 3 repeat measurements of a 30% w/v sucrose solution, and Figure 2 shows the corresponding volume size distributions. As illustrated in the published paper MRK1034 and the application note MRK1120, the second peak in the intensity plot, and also observed as the ‘bump’ in the right of the correlation function (Figure 3), is attributed to collective diffusion of the sucrose molecules.
Figure 1. Intensity size distributions obtained from 3 repeat measurements of 30% w/v sucrose solution.
Figure 2. Volume size distributions obtained from 3 repeat measurements of 30% w/v sucrose solution.
Figure 3. Correlation functions obtained from 3 repeat measurements of 30% w/v sucrose solution.
With regards to a volume distribution, there is only one peak with a mode of 0.6 nm diameter because when the Mie transformation to volume is applied, the larger peak is negligible. This 0.6 nm peak has a width with a distribution that extends down to 0.3 nm diameter (see Figure 4).
Figure 4. Volume size distributions obtained from 3 repeat measurements of 30% w/v sucrose solution.
The overplot of the three correlation functions (see Figure 3) demonstrates the repeatability of the data, which converts into the repeatability of the result.
The results reported in this article prove that the minimum size capability (diameter) of the Zetasizer Nano S or Zetasizer ZS instrument is a peak mode of 0.6 nm with a minimum size of 0.3 nm.
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.