• Oct 19, 2023
  • Laser Diffraction
  • By Aubrey Montana

Welcome to the Laser Diffraction Department at Particle Technology Labs! 

Let’s take a look around the lab space and get to know the equipment we use to produce comprehensive and reliable particle size distribution data for you.

PTL receives samples from around the world, and across multiple industries, including the pharmaceutical, environmental, beauty, food, automotive, agriculture, ceramics industries, and many more. Our chemists have to be prepared to tackle any job.

Taking a Closer Look

The first step in any analysis is reviewing the project file, reading notes from the client, and examining the sample by eye.

The chemist will then head to one of the most important instruments in our particle sizing lab – the optical microscope. Since many of the particles we receive are smaller than the naked eye can see, examination by microscopy provides insight into the general size range of the sample, as well as the overall morphology of the particulate:

  • Is there a wide size distribution? Will all of the particulate likely be measured accurately by the laser diffraction technique? Are there any outlier particles that should be discussed?
  • What is the shape of the particulate? Will the equivalent spherical diameter measurement assumptions inherent to laser diffraction be appropriate for this material, or is the sample needle-shaped or elongated, and possibly better-suited for a different technique?
  • How does the sample behave? Does the powder flow nicely, or does it clump or stick due to static? Does the sample disperse easily, or are agglomerates or aggregates observed?
  • Is the suspension concentrated enough to meet the instrument’s obscuration recommendations?

Chemist at Particle Technology Labs These factors are critical to ensure the selected technique is appropriate for the material and will help the chemist navigate their path to an accurate analysis.

Preparation is Key

Armed with information from our microscopy observations, we can begin the sample preparation process. Looking at what we know about the material and the physical properties, we can begin to examine carriers, diluents, and mixing/dispersion mechanisms. Drawing on expertise and experience, our chemists have a host of chemicals and instrumentation to choose from.

Are the particles friable, and require gentle handling? Or are there more robust agglomerates that need to be dispersed in order to measure the primary particle size? From basic equipment like balances, spatulas, and stir rods, to more advanced devices like powder rifflers, vortex mixers, stir plates, ultrasonic baths, and probes, we have the right tool to prepare any sample.

And let’s not forget another trip to the microscope to confirm we are only dispersing the sample, and not altering the particulate itself.

Particle Size Analysis is Not One Size Fits All

Once we know how the sample will be prepared, we can head over to the stars of the department, the laser diffraction instruments.

In our lab, we have a few options, including the Malvern Panalytical Mastersizer 3000, Beckman Coulter LS 13 320, and the Sympatec HELOS BR. Each of these instruments also offers an array of attachment options to accommodate both liquid dispersions and dry powder samples, allowing us to accurately measure Active Pharmaceutical Ingredients, stack test samples, wastewaters, cosmetic products, food ingredients, cement powders, etc.

But while these instruments are well known throughout the particle sizing world for their versatility and range of measurement, sometimes a different approach may be a better fit for your material. Our lab offers many other options for particle sizing. Contact us today to find the right technique for your samples, and be sure to keep an eye out for future department tours!

By Aubrey Montana, Senior Technical Sales Specialist.

Laser Diffraction

Laser Diffraction (also known as Static Light Scattering) is one of the most widely used particle sizing distribution techniques. Samples are passed through a laser beam, scattering the light and detectors measure the intensity of light scattered at fixed positions. Output is a particle size distribution.

Learn More About this Technique