Entwicklung stationärer Phasen für die Kationenaustauschchromatographie: Funktionalisierung, Charakterisierung, Anwendung

A series of structurally similar cation-exchangers comprising an adjustable ratio of strongly and weakly acidic cation-exchange sites is developed by applying modular small-molecule reactions to a polymeric substrate. Based on polystyrene-divinylbenzene particles, a material set with three different degrees of carboxylation and multiple degrees of sulfonation is prepared. Mixed-mode retention properties of the column are demonstrated using chromatographic tests and material characterization. The influence of the different functional groups on ion-exchange and partitioning is demonstrated using the available column library. A single-particle inductively coupled plasma mass spectrometry method is developed to characterize the homogeneity and the degree of functionalization. The column chemistry is optimized for the separation of 20 canonical amino acids and tested for stability in different mobile phases. The robust column enables the direct coupling with electrospray ionization mass spectrometry and the quantitation of amino acids in complex sample matrices.