Terminating centrifugation on the basis of the mathematically simulated

Abstract

A method of controlled centrifugation including automatic determination (before or during a centrifugation run) of the time to reach 'completion' (within specified limits, depending on the criteria adopted) of a centrifugal separation. By simulation, the sample solute concentration distributions are determined and examined periodically. Centrifugation completion is deemed to have been reached based on certain predetermined criteria relating to spatial changes in the sample solute concentration distributions between successive examinations. The positions of the end points of the concentration distributions or band edges of the sample solutes (transitions from regions of sample solutes to regions of no sample solutes) are determined to facilitate resolving spatial changes of the concentration distributions. The position of an end point or band edge is characterized by a specific location along the centrifuge tube where an imaginary boundary exists at which no more than a specific % of the total mass of the solute in the band lies outside said boundary. In order to avoid premature termination of centrifugation before actual equilibrium has been reached as a result of excessive frequent checks of the motion of the concentration distribution because of relatively long time scale in sedimentation, an estimate is provided of a characteristic periodic interval between successive checks of sample solute concentration distributions.