We report on experiments and numerical simulations of the centrifugal separation of solutes in aqueous solutions. The experiments are measurements of solutal concentrations in binary and ternary aqueous mixtures of seven different salts subject to centrifugal accelerations of between 57,000g and 200,000g. The evolution of the concentration profiles are measured and the sedimentation coefficients are determined. We compare our experimentally determined coefficients with those predicted by the Svedberg relation. Our numerical simulations of the diffusion and sedimentation dynamics of centrifugation agree well with the experiments and constitute a basis for a nonequilibrium centrifugal separation scheme.