Multifactor model for the optimization of selectivity in reversed-phase chromatography

✍ Scribed by Matthias Otto; Wolfhard Wegscheider

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 702 KB
• Volume: 258
• Category: Article
• ISSN: 1873-3778
• DOI: 10.1016/s0021-9673(00)96393-3

✦ Synopsis

Three variables characterizing the mobile phase composition, pH, elution strength and ionic strength, have been studied in order to construct a three-dimensional semiempirical model for predicting retention times of dibasic substances. The solutes treated quantitatively include dibasic acids and bases, an amino acid and two dipeptides.

Experimental effort was minimized by arranging them as 6 x 3 x 2 factorial design and deriving the coefficients of the model with a variable projection algorithm that separates linear from non-linear parameters.

The coeflicienls are then used to predict capacity factors, k', and relative retentions, c(, for all solute pairs in a computerized grid search. Within the limits of the model, it is an easy task to reduce the grid size to calculate all combinations of 25 pH, 20 elution strength and 10 ionic strength values. The predicted optimal selectivity was verified experimentally and the experimental retention data found to be in good agreement with the computed retention times.