Zetasizer APS Specifications, Maximum Size Limit 1.0 (r.μm)

Introduction

For the Zetasizer APS 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
• 96 well plate

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 distribution obtained from the 1.0µm polystyrene latex dispersion is 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 measurement of a traceable 1.0µm polystyrene latex dispersed in a 10mM NaCl solution

Figure 2 is the correlation function of the latex, showing some baseline noise, but no evidence of significant number fluctuations. This demonstrates the capability of the Zetasizer APS to measure particles with a size mode of 0.5µm radius.

Figure 2: Correlation function obtained from measurement of a traceable 1.0µm polystyrene latex dispersed in a 10mM NaCl solution

To characterize this size, the system has a capability of measuring the size of the distribution up to a 1.0µm radius.

Conclusions

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