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Light Scattering

par douarche - publié le





A light scattering setup is operational for ten years. This homemade set up allows us to measure the Rayleigh scattering of macromolecules in solution at different angles and at different temperatures. The static intensity measurement of the scattered light can usually characterize the mass of macromolecules, their sizes in the range 35-120 nm and their interactions. For example, these measurements have enabled us to follow the kinetics of the DNA ejection from bacteriophage. Quasi-elastic measurements allow us to determine how these macromolecules diffuse in solution ; this mode is mainly used to make measurements of hydrodynamic size ranging from 5 nm to hundreds of nanometers. A He-Ne laser of wavelength 633 nm is used as light source in the current setup. Typically a signal is detectable for macromolecules of molecular weight 10^5 g / mol diluted to 1 g / l and 300 microliters are required to perform measurements at different angles while 30 microliters sufficient for measurements at a single angle.