In continuation of our efforts to synthesize a highly dedicated strong cation exchanger, we introduce four chiral stationary phases based on a laterally substituted naphthalene core featuring chiral 2-aminocyclohexansulfonic acid as the chiral cation-exchange site. The selectors were modified with two different terminal units, which enabled immobilization to the silica support by thiolene radical reaction or azide-yne click chemistry. The chromatographic parameters of these chiral stationary phases were determined using a set of chiral amines, mainly from the family of β-blocker pharmaceuticals. The chiral stationary phases immobilized by means of click chemistry were found to be superior to those possessing the sulfide linker to the silica support. The chromatographic results and visualization of density functional theory-calculated conformations of the selectors hint at a combination of a steric and electronic effect of the triazole ring in the course of chiral resolution of the target analytes.

Chromatographic performance of a chiral stationary phase is significantly influenced by the employed solid support. Properties of the most commonly used support, silica particles, such as size and size distribution, and pore size are of utmost importance for both superficially porous particles and fully porous particles. In this work, we have focused on evaluation of fully porous particles from three different vendors as solid supports for a brush‐type chiral stationary phase based on 9‐O‐tert‐butylcarbamoyl quinidine. We have prepared corresponding stationary phases under identical experimental conditions and determined the parameters of the modified silica by physisorption measurements and scanning electron microscopy. Enantiorecognition properties of the chiral stationary phases have been studied using preferential sorption experiments. The same material was slurry‐packed into chromatographic columns and the chromatographic properties have been evaluated in liquid chromatography. We show that preferential sorption can provide valuable information about the influence of the pore size and total pore volume on the interaction of analytes of different size with the chirally‐modified silica surface. The data can be used to understand differences observed in chromatographic evaluation of the chiral stationary phases. The combination of preferential sorption and liquid chromatography separation can provide detailed information on new chiral stationary phases.

Ibuprofen separation from water by adsorption and pertraction processes has been studied, comparing 16 different membranes. Tailor-made membranes based on Matrimid, Ultem, and diaminobenzene/diaminobenzoic acid with various contents of zeolite and graphene oxide, have been compared to the commercial polystyrene, polypropylene, and polydimethylsiloxane polymeric membranes. Experimental results revealed lower ibuprofen adsorption onto commercial membranes than onto tailor-made membranes (10–15% compared to 50–70%). However, the mechanical stability of commercial membranes allowed the pertraction process application, which displayed a superior quantity of ibuprofen eliminated. Additionally, the saturation of the best-performing commercial membrane, polydimethylsiloxane, was notably prevented by atomic layer deposition of (3-aminopropyl)triethoxysilane.

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Chiral zwitterion ion exchangers represent efficient chiral stationary phases for stereoselective resolution of various analytes including chiral acids, bases, and zwitterions. In this contribution, we have focused on utilization of chiral zwitterionic sorbents, denoted as ZWIX (+A) and ZWIX (−A). These are analogical chiral systems to commercially available columns, Chiralpak ZWIX (+) and Chiralpak ZWIX (−), which are usually operated with buffered mobile phases. In this contribution, we have studied the enantiorecognition power of the ZWIX (+A) and ZWIX (−A) columns on a series of dipeptides operated under buffer‐free reversed‐phase conditions. Retention characteristics of zwitterionic dipeptides are discussed using an electrostatically driven adsorption model, which provides a good fit with both monotonous and U‐shaped curves.