Zetasizer μV Specifications : Proof of Maximum Size Limit

Introduction

For the ZetasizerµV instrument, the maximum size specification (radius) is a peak mode of 0.5µm with a maximum size of 1.0µm. This technical note contains details of the experimental procedures and results obtained from measurements of a NIST traceable polystyrene latex standard as demonstration of these maximum size specifications.

Experimental

Materials

• 1.0µm (diameter) polystyrene latex from the Thermo Scientific Duke Standards NIST traceable 4000 series (part number 4010A) supplied at a 1%w/v concentration
• 10mM NaCl
• Sizing cuvettes

Method

The polystyrene latex standard sample was prepared for measurement by adding 100µl of the latex to 10ml of the 10mM NaCl solution. The measurements were taken at 25°C

Results

The intensity size distributions obtained from repeat measurements of the 1.0µm polystyrene latex dispersion are shown in figure 1. The distribution shows the low polydispersity measured for this monodisperse sample. At the maximum size limit, the concentration of the latex has to be sufficient to avoid number fluctuations.

Figure 1: Intensity size distribution obtained from 3 repeat measurements of a traceable 1.0µm polystyrene latex dispersed in a 10mM NaCl solution

Figure 2 shows the correlation functions of the latex, showing some baseline noise, but no evidence of significant number fluctuations. This demonstrates the capability of the Zetasizer µV to measure particles with a size mode of 0.5µm radius. To characterize this size, the system has a capability of measuring the size of the distribution up to a 1.0µm radius.

Figure 2: Correlation functions obtained from 3 repeat measurements of a traceable 1.0µm polystyrene latex dispersed in a 10mM NaCl solution

Conclusions

The results reported in this technical note confirm that the maximum size capability (radius) for the Zetasizer µV is a peak mode of 0.5µm with a maximum size of 1.0µm.