In this series of publications, experimental results for the liquid-liquid equilibrium in organic/aqueous two-phase systems containing a tertiary amine (tri-n-octylamine) and a mineral acid (nitric, hydrochloric or sulfuric acid) are presented and discussed in combination with a thermodynamic model for describing such phase equilibria. In the first part, the organic solvent was toluene. In the present part, toluene is replaced by methylisobutylketone. (C) 2003 Elsevier B.V. All rights reserved.