Sequential simplex optimization and multichannel detection in HPLC: Application to method development

Abstract

The sequential simplex procedure for the optimisation of mobile phase composition in high-performance liquid chromatography (HPLC) is combined with multichannel detection. The operating software already available in a commercial LC system is exploited and extended to incorporate a number of new routines developed to facilitate HPLC method development. An efficient stop criterion for automated simplex procedures is proposed, based on continuous comparison of the chromatographic response function attained with that predicted. The theoretical basis is developed for a new peak homogeneity test, based on the wavelength sensitivity of the chromatographic peak maximum. An algorithm for assigning peak elution order, based on peak areas at multiple wavelengths, is developed for cases where multiple optima are recorded. The simplicity and practical utility of these techniques are demonstrated in the context of an HPLC separation method developed for a model system of six solutes.