Simplex-optimized chromatographic resolution of selected ionic liquid cations utilizing a polar reversed-phase system.

This study reports on optimization of the RP-HPLC separation of imidazolium and pyridinium ionic liquid cations using a variable-size simplex algorithm. Under the optimized conditions, all critical pairs of ionic liquids were successfully separated in a single chromatographic run. The mobile phase at the point corresponding to the optimum consisted of 10% MeOH and 90% 15 mM KH(2)PO(4)/H(3)PO(4) with pH 3.43. The coefficients of asymmetry for all of the compounds analyzed at the simplex algorithm optimum ranged from 0.83 to 2.91.