Evaluation of the information content of sedimentation equilibrium data in self-interacting systems.

Fitting r = f(c) as opposed to the usual c = f(r) to the inverted form of the sedimentation equilibrium equation for interacting solute (INVEQ algorithm), it is shown by detailed simulation and by experimentation that stable, simultaneous estimates can be retrieved for both virial (2nd BM/3rd CM) and specific interaction (K(a)) terms. In suitable systems estimates for two distinct second virial (BM) and single K(a) terms can equally be defined. Whilst cell loading level is critical, noise level in the interference fringe data is shown to have surprisingly little influence on these outcomes.