Seven important specifications in light-scattering instruments

When you’re buying something important, it pays to do your research. You don’t want to end up with a laptop that doesn’t have enough memory or a car with a poor gas economy. The same applies to finding the right light-scattering instrument for your lab: you want to be sure you’re investing in a system that’s optimized for your samples and applications.

To help you identify the right machine for you, we’ve identified seven key specifications to consider.

The power of seven

1. Measurement type. Luckily, you don’t have to decide between dynamic light scattering (DLS) and electrophoretic light scattering (ELS): our Zetasizer Advance range offers both techniques, so you can measure nanoparticle size and zeta potential with one single instrument, saving you time, space, and money. Plus, our Ultra Red model provides particle concentration measurements, too.
2. Measurement angles. 90° was the standard for many years and remains an option for limited budgets, but some machines use backscatter measurements (usually 170°–175°) to increase your measurement volume eight-fold and thus improve sensitivity for low-concentration samples.
3. Multiple angles. This allows for a significant improvement in size resolution. Our Zetasizer Ultra measures from three different angles, combining the raw data to give a single result with a higher signal-to-noise ratio and greater precision.
4. Sample volume. If there’s a chance you’ll have limited sample quantities, you should opt for an instrument that can handle low volumes. In the Zetasizer, you can use quantities as low as 3μL for DLS and 20μL for ELS.
5. Particle size range. DLS and ELS have slightly different limits for particle sizes – but don’t just look at the maximum and minimum values of an instrument: what really matters is the range you need. Make sure this factor is optimized in your chosen instrument, giving you the most reproducible results.
6. Concentration range. In materials applications, the concentration range you need in your light-scattering machine will depend on the samples, although there’s often a need to measure higher concentrations in pigments and inks, for example. Our Zetasizer Advance systems can handle anything from a 0.1mg/mL solution of latex to 40wt% solid suspensions.
7. Laser power. Although it sounds exciting, laser power isn’t usually a good guide to an instrument’s performance. Instead, look at the optical design and sensitivity-enhancing features, which can more than make up for a seemingly low-powered laser. Higher laser power comes with the risk of more noise, sample heating, and greater viscosity – so remember that more power isn’t always better. Our systems use either a 4mW or 10mW laser in combination with other innovative features to give excellent results for even the most challenging samples.

Guidance and solutions from Malvern Panalytical

Whether you’re measuring nanomaterials or colloids, polymers, or proteins, make sure you choose a light-scattering instrument that fits your sample and measuring needs – and avoid buyer’s remorse further down the line!

Take a look at our new white paper for more information about the essential specifications to keep in mind – and find exactly the technology you’re looking for in Malvern Panalytical’s Zetasizer range!