engleski

Computer assisted gradient elution optimization in ion chromatography I. Simplex based approach

Gradient elution is almost unavoidable in conventional reversed phase liquid chromatography and rapidly is increasing its popularity in ion chromatography. Implementation of gradient elution implies finding the suitable gradient program, which is usually, numerically speaking, extremely complex due to the fact that number of gradient programs that can be implemented is virtually unlimited. Thus, sequential searching methodology might offers reasonable solution if properly modified and implemented in global optimization routine. This work focused on development of simplex based methodology for gradient elution optimization in ion chromatography. For this purpose, an empirical or mechanistic model, able to predict the isocratic retention time is developed using less than ten consecutive isocratic runs. Gradient retention times are predicted on the basis of isocratic model using numerical integration procedure and providing model able to predict virtually unlimited number of gradient profiles. The simplex based routine was developed in order to search the optimization hyperplane. Different experimental design methodologies were implemented enabling selection of different set of initial experimental data. Developed procedure incorporates possibility of number of gradient segments selection. Different chromatography objective functions were used and compared in combination with previously commented parameters. Obtained results clearly show that developed methodology offers advanced methodology for gradient elution optimization in ion chromatography.

ion chromatography; gradient elution; optimization; simplex approach

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