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See detailCombination of Partial Least Squares regression and Design of Experiments to model the retention of pharmaceuticals in Supercritical Fluid Chromatography
Andri, Bertyl ULiege; Dispas, Amandine ULiege; Marini Djang'Eing'A, Roland ULiege et al

in Journal of Chromatography. A (2017)

This work presents a first attempt to establish a model of the retention behaviour for pharmaceutical compounds in gradient mode SFC. For this purpose, multivariate statistics were applied on the basis of ... [more ▼]

This work presents a first attempt to establish a model of the retention behaviour for pharmaceutical compounds in gradient mode SFC. For this purpose, multivariate statistics were applied on the basis of data gathered with the Design of Experiment (DoE) methodology. It permitted to build optimally the experiments needed, and served as a basis for providing relevant physicochemical interpretation of the effects observed. Data gathered over a broad experimental domain enabled the establishment of well-fit linear models of the retention of the individual compounds in presence of methanol as co-solvent. These models also allowed the appreciation of the impact of each experimental parameter and their factorial combinations. This approach was carried out with two organic modifiers (i.e. methanol and ethanol) and provided comparable results. Therefore, it demonstrates the feasibility to model retention in gradient mode SFC for individual compounds as a function of the experimental conditions. This approach also permitted to highlight the predominant effect of some parameters (e.g. gradient slope and pressure) on the retention of compounds. Because building of individual models of retention was possible, the next step considered the estab- lishment of a global model of the retention to predict the behaviour of given compounds on the basis of, on the one side, the physicochemical descriptors of the compounds (e.g. Linear Solvation Energy Relationship (LSER) descriptors) and, on the other side, of the experimental conditions. This global model was established by means of partial least squares regression for the selected compounds, in an experimental domain defined by the Design of Experiment (DoE) methodology. Assessment of the model’s predic- tive capabilities revealed satisfactory agreement between predicted and actual retention (i.e. R2 = 0.942, slope = 1.004) of the assessed compounds, which is unprecedented in the field. [less ▲]

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See detailModélisation du comportement chromatographique en SFC
Andri, Bertyl ULiege; Dispas, Amandine ULiege; Hubert, Philippe ULiege et al

Conference (2016, January 21)

Detailed reference viewed: 13 (2 ULiège)
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See detailInnovative green supercritical fluid chromatography development for the determination of polar compounds
Dispas, Amandine ULiege; Lebrun, Pierre ULiege; Sassiat, Patrick et al

in Journal of Chromatography. A (2012), 1256

In the context of green analytical chemistry, a supercritical fluid chromatography method was developed. In order to prove the potential of this technology, a worst case was selected, i.e. the separation ... [more ▼]

In the context of green analytical chemistry, a supercritical fluid chromatography method was developed. In order to prove the potential of this technology, a worst case was selected, i.e. the separation of very polar compounds. For that purpose, an innovative methodology based on design of experiments (DoE) and design space (DS) was previously developed and successfully tested on liquid chromatography. For the first time, this methodology was applied to a supercritical fluid chromatography (SFC) separation. First, a screening design was used to select the stationary phase and the nature of the mobile phase based on a maximization of the number of peaks eluted and a minimization of the number of co-eluted peaks. Then, a central composite design with orthogonal blocks defined a set of experiments used to model the retention times of each peak at the beginning, the apex, and the end. The gradient slope, the isocratic plateau before the gradient, the temperature, and the concentration of trifluoroacetic acid (TFA) in the mobile phase were the potentially influential factors. The critical quality attributes (CQAs), i.e. the separation (S) between peaks of the most critical pair, and the analysis time were the responses considered to assess the quality of the separation. The DS was computed as the multidimensional subspace where the probability for the separation and analysis time criteria to be within acceptance limits was higher than a defined quality level. The DS was computed propagating the prediction error from the modeled responses to the quality criterion using Monte Carlo simulations. The optimal condition was predicted at a gradient slope of 3.8% min−1 to linearly modify the modifier proportion between 5 and 40%, an isocratic time of 3 minutes, a concentration of TFA of 25 mM, and a temperature of 60.5 °C. This optimal condition was experimentally tested to confirm the prediction. Furthermore, chromatographic conditions included in the DS and on the limits of the DS were experimentally tested to assess the robustness of the developed SFC method. [less ▲]

Detailed reference viewed: 84 (21 ULiège)