Molecular Weight of polymers dispersed in solution: On a sample volume of 10-40 µL, the instrument can determine a range between 1kDa to 25 MDa. It can analyse a wide range of suspension concentrations (0.1 ppm to 40% v/v depending on the sample type). Dynamic Light Scattering Theory Simplified theoretical background Issues Problems faced during experiments Soln Suggested solutions S. It claims an accuracy of 0.12 µm.cm/V.s and a sensitivity of 10 mg/mL (BSA). Dynamic light scattering measures variation in scattered intensity with time at a fixed scattering angle (typically 90o) ,while static. Minimum sample volume required is 175 µL. The light scattering: ccording to the semi-classical light scattering theory Berne and Pecora, 'Dynamic Light scattering' John Wiley, 1975, when light impinges on matter, the electric field of the light induces an oscillating polarization of electrons in the molecules. Zeta Potential: It can measure wide range of zeta potentials for particles in the size range 1 nm – 100 µm, depending on the type of sample. It claims an accuracy of ☒% with a precision of ☑%. This technique is commonly known as dynamic light scattering (DLS), but is also called photon correlation spectroscopy (PCS) and quasi-elastic light. Particle Size and Molecular Size: It can measure size between 0.3 nm to 6 µm with a minimum volume 10 µL of sample suspension. It can also be used to probe the behaviour of complex fluids such as concentrated polymer solutions. Dynamic Light Scattering (DLS) principle can be used to determine the size distribution profile of small particles in suspension or polymers in solution. When the potential is low, attraction exceeds repulsion and the dispersion will break and flocculate. HR was measured with the DLS sensor at 5 different sites for 15 min each. For molecules and particles that are small enough, a high zeta potential will confer stability, i.e., the solution or dispersion will resist aggregation. Static & Dynamic Light Scattering First quantitative experiments in 1869 by Tyndall (scattering of small particles in the air Tyndall effect) 1871 Lord Rayleigh started a quantitative study and theory Basic idea: incident monochromatic linearly polarized light beam incident on a sample. Keywords: Noninvasive measurementDynamic light scatteringNeonateHeart rate. The zeta potential indicates the degree of repulsion between adjacent, similarly charged particles (e.g., the vitamins) in a dispersion. The significance of zeta potential is that its value can be related to the stability of colloidal dispersions (e.g., a multivitamin syrup). DLS is used to size particles from below 5 nm to several microns. It can determine particle size distribution, particle zeta potential (related to the magnitude of the electrical charge at the particle surface) and molecular weight of large polymeric substances dispersed in water. Dynamic Light Scattering (DLS) is also known as Photon Correlation Spectroscopy (PCS). The DLS Particle Size and Zeta Potential Analyzer is a user-friendly system for colloidal, nanoparticulate and macromoleculer characterization.
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