Global retention models and their application to the prediction of chromatographic fingerprints

Experimental design and re-parameterization of the Neue-Kuss model for accurate and precise prediction of isocratic retention factors from gradient measurements in reversed phase liquid chromatography

“…These authors proposed using a ref corresponding to the organic phase composition for the maximum retention factor in the experimental design. In the present work, we extend this re-parameterization strategy to the NK model, which is frequently use for fitting reversed phase LC retention factors [1,[3][4][5][10][11][12]. We will show that this improves the results obtained in the fitting procedure.…”

“…One tool for rationalizing and understanding the retention of molecules has been the development of numerous models that express the retention factor (k) as a function of the mobile phase composition [1]. These models include the linear solvent strength (LSS) model, [2], the Neue-Kuss (NK) model [3][4][5], the quadratic model [6], an enhanced LSS model that allows for variations in the elution degree [7], the Jandera model [8], as well as many others [1,9,10]. These models have all been successfully used in many situations, depending on the mode of chromatography and the range of mobile phase compositions.…”

“…A further difficulty in using gradient experiments to provide fits that will yield parameters that provide accurate prediction of both isocratic and gradient retention factors, is finding an appropriate experimental design for the gradient experiments, specifically the initial mobile phase composition, I, the final mobile phase composition, F, and the gradient time, tG. As a part of the present study, we develop a strategy to identify a minimal number of experiments (6)(7)(8)(9)(10) that can provide adequate data to allow for successful fits to the reparameterized NK equation. Here, we have tested this design strategy with both simulations and experimental data.…”

Simultaneous effect of different chromatographic conditions on the chromatographic retention of pentapeptide derivatives (HGRFG and NPNPT)

“…Considering the influence of the polarity of the solute, stationary phase, and mobile phase on k, another linear model was proposed to accurately describe k, which represents the linear relationship between the retention rate and the polarity of the eluent ( Gisbert-Alonso et al, 2021 ; Zhu et al, 2022 ); the relationship is as follows: where p is the parameter describing the polarity of the solute, and are the standard polarity parameters of the mobile and stationary phases, and is the retention factor when the polarity of the mobile phase is the same as that of the stationary phase. Numerous experimental studies have shown that for a specific column and water-methanol mobile phase, the parameters of Eq.…”