The food, pharmaceutical, and materials science industries, among others, analyze different particle sizes during their research and manufacturing processes. This essential step can be conducted with the help of the right equipment. One must consider the samples, particle dimensions, and test scope. Some popular options or techniques are:
- Dynamic light scattering (DLS)
- Static light scattering (SLS)
- Direct image analysis
- Laser diffraction
- The contribution of different methods in particle size analysis
Each of these methods differently contributes to the ultimate goal. However, choosing the proper technique is crucial. For example, sieve analysis is an old method that uses different mesh-sized sieves to separate a sample by particle size. It continues until the smallest mesh size is reached. You can use sieves and sieve shakers to analyze particle sizes ranging from 20 μm to 125 mm. Agriculture, mining, and construction sectors rely on this system.
The laser diffraction method includes tracking the scattered laser beam patterns through the distributed particle sample to estimate the particle size. These analyzers can calculate the size of particles from 0.1 μm to 3 mm. Cosmetic, food, and pharma industries use them for emulsions and powdery materials. However, advanced techniques like DLS monitor the fluctuating strength of the scattered light produced by Brownian motion in suspended particles. These fluctuations help estimate the distribution of particle sizes. A unique type of dynamic light scattering instrument is used for this. You can refer to them as DLS analyzers. If you pick the right equipment, you can measure particles from 1nm to 10μm. This technique can analyze suspended particles like proteins, nanoparticles, and more. Let’s learn more about this widely used process.
- Overview of dynamic light scattering
DLS instruments can track the particles’ Brownian motion. This scientific concept reveals that tiny particles will rush while the bigger ones glide slowly in a liquid. When light is scattered or diffused by particles, you get information about dispersion speed and the size distribution. As hinted earlier, you can use this method to examine and characterize highly concentrated or diluted nanoparticles. You can also learn about molecular concentration and weight that can change the particles’ behavior in a solution.
- A few technical details about DLS
The instrument used in this technique can record the optical scattering signal to measure the motion of the particles. Earlier models could capture this from a fixed angle. However, newer models are much more advanced. You can use them to track particle movement from various angles. It can enable you to simultaneously examine a sample’s large and small particles. It also increases the reliability of the results because the chances of going wrong with your analysis are slim. Do you work with complicated biological samples or polydisperse formulations? In that case, modern DLS instruments are worth considering.
You can depend on DLS instruments to estimate the average particle size and size variation in suspended form. The results can be achieved faster without requiring much sample preparation. Since it’s also a non-invasive process, your samples will be protected. They will not undergo physical changes due to damage or disturbance. You cannot expect this with processes like electron microscopy. Nevertheless, choose your equipment wisely. The manufacturing company should be well-established.
