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Diffusional boundary spreading in the ultracentrifuge
Author(s) -
Weiss George H.,
Dishon Menachem
Publication year - 1970
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1970.360090710
Subject(s) - chemistry , diffusion , perturbation (astronomy) , concentration gradient , singular perturbation , boundary (topology) , sedimentation , pressure gradient , thermodynamics , mathematical analysis , mechanics , physics , mathematics , chromatography , geology , paleontology , quantum mechanics , sediment
A common approximation for deriving solutions to the Lamm equation is to neglect diffusion. This paper presents a singular perturbation technique that allows one to estimate the band spreading due to nonzero diffusion coefficient. We illustrate the general mathematical technique by its application to sedimentation when pressure effects are important. Comparison of the approximate solution with accurate numerical solutions shows that the relative errors are of the order of 1% both for concentration and concentration gradient for parameters of chemical interest.