The new Zetasizer Ultra is our most advanced system for the measurement of particle and molecular size, particle charge and particle concentration, and represents the most intelligent and flexible instrument in the Zetasizer range.  
 
This flagship instrument enjoys all the benefits afforded by ZS Xplorer software, in terms of ease of use, analysis speed and data confidence, and also offers two unique measurement capabilities: Multi-Angle Dynamic Light Scattering (MADLS®) and Particle Concentration, to offer even greater insight into your samples. 
 
Dynamic Light Scattering (DLS) is used to measure particle and molecule size. DLS measures the diffusion of particles moving under Brownian motion and converts this to particle size and particle size distribution using the Stokes-Einstein relationship. Non-Invasive Back-Scatter (NIBS) technology is incorporated to give the highest sensitivity within the broadest range of sizes and concentrations. DLS is a highly flexible sizing method which is rapid, accurate and repeatable. It requires only small volumes of sample for analysis, and is non-destructive. This technique is material-independent and therefore extremely widely applicable. 
 
Multi-Angle Dynamic Light Scattering (MADLS) is also incorporated in the Zetasizer Ultra, to offer the highest resolution and angular-independent size distribution analysis. MADLS also enables the simple, calibration-free measurement of particle concentration in homogeneous sample types, covering a wide range of materials. 
 
Electrophoretic Light Scattering (ELS) is used to measure zeta potential. An electric field is applied to a solution of molecules or a dispersion of particles which move with a velocity related to their charge. This velocity is measured using a patented laser interferometric technique called M3-PALS (Phase Analysis Light Scattering). This enables the calculation of electrophoretic mobility, and from this, the zeta potential and zeta potential distribution of a sample. 
 
The use of ELS commonly relates to stability and formulation applications. Particles or molecules with no net charge may bind together, which may be a challenge in systems such as protein formulations which are prone to aggregation. Particles or molecules which have either a net positive or net negative charge will better maintain a distance from one another, creating a stable system. The formulation containing these particles or molecules is very influential on their charge state, and changes to formulation attributes such as pH, additive concentration and ionic concentration can impact product stability and shelf life. 
 
ZS Xplorer Software Suite 
 
The software is designed to be very easy to use, even whilst enabling the rapid construction of complex methods. Information on the sample, its conditions, and the variables to be tested are entered at the beginning of a run, and ZS Xplorer uses this information intelligently to optimize the method for that sample. A deep learning empowered data quality guidance system provides feedback on results and offers clear advice on how data may be improved if required. 
 
Options 
 
The MPT-3 Auto titrator enables study of the effect of changes in pH. 
 
A range of disposable and reusable cells are available to optimize the measurement in terms of sample volume and concentration, including the new low volume disposable sizing cell kit, which offers the dual benefits of size measurements in as little as 3uL, and extension to the upper size range of DLS measurements, due to the suppression of convection currents.