Dynamic light scattering (DLS), which is also known as photon correlation spectroscopy(PCS) or quasi-elastic light scattering(QELS), is an analytical technique, one of the most popular methods used to determine the size of particles, and radius distribution of small particles in suspension or polymers in solution samples.
In the scope of DLS, temporal fluctuations are usually analyzed by the intensity or photon auto-correlation function (ACF). A monochromatic light beam, such as a laser, would be shined onto the tested solutions with spherical particles in Brownian motion, causing Doppler Shift when the light hits the moving particle, changing the wavelength of the original light. The change, is related to the size of the particle. It is possible to compute the sphere size distribution and issue a detailed description of the particle’s motion in the tested medium, measuring the diffusion coefficient of the particle through ACF. Meanwhile, DLS can also be used to probe the behavior of complex fluids such as concentrated polymer solutions.
In practice, DLS can be used to determine the size distribution of various particles including proteins, polymers, micelles, carbohydrates, and nanoparticles. If the system is not disperse in size, the mean effective diameter of the particles can be determined since the measurement depends on not only the size of the particle core, but also the size of surface structures, particle concentration, and the type of ions in the medium.
Generally, as an analytical technique, DLS has the advantages as below:
Accurate, Reliable and Repeatable Particle Size Analysis
Direct Analysis of the Native Samples with Simple or no Sample Preparation
Simple Set-Up and Fully Automated Measurement
Size Measurement of Sizes < 1nm
Size Measurement of Molecules with MW < 1000Da
Low Volume Requirement
Compliance with Regulatory Standards
If necessary, DLS can be utilized to obtain several important parameters of interest, such as molecular weight, radius of gyration, translational diffusion constant and so on. Our experienced analysts and technicians can help you to design and perform the analytical experiments after technical discussion.