The SZ-100 nanopartica series instruments are flexible analytical tools for characterizing the physical properties of small particles. Depending on the configuration and application the system can be used as a particle size analyzer, or also used to measure zeta potential, molecular weight, (MW) and second virial coefficient (A2). Typical applications for the SZ-100 include nanoparticles, colloids, emulsions, and submicron suspensions.
Particle size analysis is performed by dynamic light scattering (DLS). Depending on the physical properties of the sample, the dynamic range is 0.3 nm – 8 µm. The lower limit is influenced by concentration, how strongly the sample scatters light, and the presence of large, unwanted particles. The upper limit is influenced by the density of the sample since DLS is modeled on all motion coming from Brownian motion, not gravitational settling.
The charge on the surface of particles is characterized by the SZ-100 by measuring the zeta potential of a suspension. The sample is injected into a disposable cell and a measurement of the particle electrophoretic mobility results in the calculated zeta potential. The zeta potential of the sample is most often used as an indicator of dispersion stability. Large magnitude zeta potential values indicate that an electrostatically stabilized suspension will remain stable. The zeta potential is often measured as a function of pH or other change in the chemistry to help formulators create new products with a long shelf life. Conversely identifying conditions at which the zeta potential is zero (that is, the sample is at the isoelectric point) allows one to choose optimum conditions for flocculating and separating particles.
The same instrument can also be used to measure the molecular weight and second virial coefficient of proteins, polymers, and other molecules. The user prepares several solutions with known concentrations and then uses the system in a static light scattering mode to create a Debye plot, which results in a calculation of both MW and A2.
- Particle size, zeta potential, molecular weight, and second virial coefficient all in one instrument
- Wide range of particle sizes and concentrations
- Particles size measurements at both 90° and 173°
- Multiple particle size measurement modes for working with small particles and weak scatterers
- Small volume cells for both particle size and zeta potential
Manufactured by HORIBA
Particle size: Dynamic Light Scattering (DLS) technique
Zeta potential: Laser doppler electrophoresis technique
Molecular weight: Static light scattering Debye plot technique
Power supply: AC 100-240V, 50/60Hz, 150VA
Laser: DPSS 532 nm, 10 mW Class I
Interface: USB 2.0, between the analyzer and PC
External dimensions: 385(D) ´ 528(W) ´ 273(H) mm (Except for projections)
Mass approx: 25kg
Temp control range: 1-90℃ for particle size, 1-70℃ for zeta potential
Operating temp and humidity: 15-35℃, Relative humidity = 85% or less, no condensation
Condensation control: Purge port connection available
Particle size is measured by the SZ-100 using dynamic light scattering (DLS). The sample particles in the cell experience Brownian motion. A light source is introduced into the cell, and the scattered light is collected at either 90° or 173° as shown in the diagram below. The system automatically selects the optimum scattering angle and cell position depending on the sample concentration and intensity.
The signal obtained from the scattered light is fed into a multi-channel correlator that generates a function used to determine the translational diffusion coefficient of the particles analyzed. The Stokes-Einstein equation is then used to calculate the particle size. A range of sample cells are available depending the sample volume and goals of the measurement.
Zeta potential analysis is made either in a disposable plastic cell, or a dip cell. The system measures the sample conductivity, applies an electric field, and then measures the motion of the particles using electrophoretic light scattering. The direction of the particle motion determines if the charge is negative or positive, and the speed of the particles determines the magnitude of the charge (zeta potential). The reported zeta potential result can then be used as an indicator of the dispersion stability.
The SZ-100 calculates absolute molecular weight by performing static light scattering measurements on a sample at several different concentrations. A Debye plot of KC/R vs. concentration produces results for both molecular weight and second virial coefficient.
All of these measurements are performed by the menu-driven, easy to use software. Appropriate sample measurement conditions are chosen as the user steps through the navigation sequence. Default parameters allow novice users to generate good, repeatable data. Advanced options are available on additional screens for more expert users who know more about the sample being analyzed.
Particle size cells
Semi-micro disposable cell
Cell with lid
Micro cell (90° only)
Zeta potential cells
Disposable zeta potential cells for aqueous measurements. Box of 20 Volume = 100 µL
Non-aquoeus zeta potential cell. Volume = 100 µL