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Size exclusion chromatography with multi-angle static light scattering (SEC-MALS) is used to measure masses of macromolecules. Size-exclusion chromatography (SEC) separates molecules based on hydrodynamic volume, but is dependent on similarity to a set of reference standards for accurate mass determination and fails for elongated or sticky proteins. Multi-Angle Light static Scattering (MALS) is used to accurately measure the intensity of scattered light, which is proportional to weight-averaged molar mass in solution. Combining SEC, MALS and concentration detectors in an SEC-MALS experiment allows for more accurate mass measurements that SEC or MALS alone.
Dynamic Light Scattering (DLS) measures the time-dependent fluctuations in scattered light. These fluctuations are directly related to rate of diffusion of the molecule through the solvent, and can be used to measure hydrodynamic radius (Rh) of the particles in solution.