Zetasizer Nano S/ZS Specifications Maximum Concentration Limit for Size 40% w/v

Introduction

For the Zetasizer Nano S or ZS instrument, the maximum concentration specification for size measurements is 40% w/v. This technical note contains details of the experimental procedures and results obtained from measurements of a nominally 100nm silica suspension at a concentration of 40%w/v as demonstration of this maximum concentration limit.

Experimental

Materials

• 40% w/v colloidal silica suspension with a nominal size of 100nm
• DTS0012 disposable sizing cuvettes

Method

The 40% w/v silica suspension was placed into a DTS0012 disposable sizing cuvette with care being taken to ensure no air bubbles were present. The measurements were taken at 25°C.

Results

The intensity size distributions obtained from 5 repeat measurements of a nominally 100nm silica suspension at a concentration of 40% w/v are shown in figure 1, demonstrating the repeatability of measurement at this concentration.

Figure 2 is an overplot of the correlation functions of these measurements, showing an excellent repeatability and an intercept of 0.77 indicating a good signal and a low probability of multiple scattering which would affect the size measured.

Figure 1: Intensity size distributions obtained from 5 repeat measurements of a nominally 100nm silica suspension at a concentration of 40%

Figure 2: Correlation functions obtained from 5 repeat measurements of a nominally 100nm silica suspension at a concentration of 40%

Conclusions

The results reported in this technical note confirm that the maximum concentration specification for size measurements on the Zetasizer Nano S or ZS is 40% w/v.