DCDT
DCDT processes sedimentation velocity data using the time derviative to eliminate systematic noise and produces a plot of the concentration gradient with respect to the radial axis expressed in svedbergs. The DCDT plot [g(s) vs s] represents a snapshot of the sedimentation process at a particular time. It preserves diffusion information allowing accurate estimation of diffusion coefficients and, therefore, calculation of molar masses by fitting the g(s) vs s function to a gaussian and extracting the diffusion coefficient from the variance of the gaussian.
Advantages of g(s*) from dc/dt
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The DCDT plot [g(s) vs s] represents a snapshot of the boundary at a particular time.
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Uses a narrow time interval.
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Boundary shape is preserved.
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Diffusional information is preserved allowing accurate estimates of diffusion coefficients - even for multiple overlapping boundaries - and, therefore, reliable calculation of molar masses.
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Boundary spreading characteristics of interacting systems are also preserved.