Optimization of gradient profiles in ion-exchange chromatography using computer simulation programs

Optimization procedure of gradient separations in ion-exchange chromatography using simplex optimization method in combination with the computer simulation program for ion-exchange chromatography is presented. The optimization of parameters describing gradient profile for the separation in ion chromatography is based on the optimization criterion obtained from calculated chromatograms. The optimization criterion depends on the parameters used for calculations and thus exhibits the quality of gradient conditions for the separation of the analytes. Simplex method is used to calculate new gradient profiles in order to reach optimum separations for the selected set of analytes. The Simplex algorithm works stepwise, for each new combination of parameters that describe the gradient profile a new calculation is performed and from the calculated chromatogram the optimization criterion is determined. The proposed method is efficient and may reduce the time and cost of analyses of complex samples with ion-exchange chromatography.

Simulated chromatogram (gradient ion chromatography) obtained with the experimental parameters from simplex optimization procedure regarding minimal distance between adjacent peaks (below), in comparison with the experimental chromatogram (above). Gradient programs used: isocratic elution at 11.4 mM KOH for 1.5 min, linear gradient from 11.4 mM to 58.8 mM KOH in 15 min, then isocratic elution.Figure optionsDownload as PowerPoint slideHighlights
► We report on simplex optimization of gradient parameters in ion chromatography.
► Simplex algorithm is merged with the simulation algorithm for ion chromatography.
► Optimization is further applicable to faster simulation programs.
► Simulated and experimental chromatograms of a complex sample are in good agreement.