Characterization of mesoporous aluminosilicate materials by means of inverse liquid chromatography

Hansen Solubility Parameters Applied to the Extraction of Phytochemicals

In many analytical chemical procedures, organic solvents are required to favour a better global yield upon the separation, extraction, or isolation of the target phytochemical analyte. The selection of extraction solvents is generally based on the solubility difference between target analytes and the undesired matrix components, as well as the overall extraction procedure cost and safety. Hansen Solubility Parameters are typically used for this purpose. They are based on the product of three coordinated forces (hydrogen bonds, dispersion, and dipolar forces) calculated for any substance to predict the miscibility of a compound in a pure solvent, in a mixture of solvents, or in non-solvent compounds, saving time and costs on method development based on a scientific understanding of chemical composition and intermolecular interactions. This review summarises how Hansen Solubility Parameters have been incorporated into the classical and emerging (or greener) extraction techniques of phytochemicals as an alternative to trial-and-error approaches, avoiding impractical experimental conditions and resulting in, for example, saving resources and avoiding unnecessary solvent wasting.

Hansen solubility parameters obtained via molecular dynamics simulations as a route to predict siloxane surfactant adsorption

HYPOTHESIS

The Hansen Solubility Parameters (HSP) derived from Molecular Dynamics (MD) simulations can be used as a fast approach to predict surfactants adsorption on a solid surface. Experiments and simulations: We focused on the specific case of siloxane-based surfactants adsorption on silicon oxide surface (SiO₂), encountered in inkjet printing processes. A simplified atomistic model of the SiO₂ surface was designed to enable the computation of its solubility parameter using MD, and to subsequently determine the interactions of the SiO₂ surface with the siloxane-based surfactant and the various solvents employed. Surfactant adsorption was characterized experimentally using contact angle goniometry, ellipsometry, XPS and AFM.

FINDINGS

Comparison of the numerical results with experiments showed that the HSP theory allows to identify the range of solvents that are likely to prevent surfactant adsorption on the SiO₂ surface. The proposed approach indicates that polar solvents, such as acetone and triacetin, which are strongly attracted to the silicon oxide surface might form a shield that prevents siloxane-based surfactants adsorption. This simple approach, can guide the selection of adequate solvents for surfaces and surfactants with specific chemical structures, providing opportunities for controlling interfacial adsorption.