A Method for Separating According to Mass a Mixture of Macromolecules or Small Particles Suspended in a Fluid, I. Theory

We have developed a method for separating a mixture of macromolecules or small particles suspended in a fluid. The separation is according to mass, or more precisely, according to what we shall call the effective mass, the mass of a particle minus the mass of the fluid it displaces. We expose the fluid to a steady acceleration, allowing the suspended particles to distribute themselves in equilibrium atmospheres whose scale heights, h,, depend on the effective masses, me, through the familiar relation