Complementary mobile-phase optimisation for resolution enhancement in high-performance liquid chromatography

An optimisation methodology in high-performance liquid chromatography (HPLC ) is presented for the selection of two or more mobile phases having an opt imal complementary resolution. The complementary mobile phases (CMPs) are s elected in such a way that each one resolves optimally only some compounds in the mixture, while the remainder, resolved by the other mobile phase(s), can overlap among them. The methodology is based on the computation of a p eak purity measurement for each solute, using an asymmetrical peak model fo r peak simulation. Two global resolution criteria (product of elementary re solutions and worst elementary resolution) and two methods for solving the problem (a systematic examination of all possible solute arrangements, and the use of genetic algorithms to expedite the calculation time) were used t o find the optimal CMPs. The CMP optimisation methodology was applied to th e resolution of a mixture of 10 diuretics and P-blockers, which could not b e resolved using a single mobile phase; virtual baseline resolution was ach ieved, however, with two CMPs. (C) 2000 Elsevier Science B.V. All rights re served.