Preparation of Polyamine-Silica Macrocyclic Chromatographic Stationary Phase for the Separation of Aromatic Compounds

Reversed-phase chromatography stationary phases (such as C18) are widely used in commercial high-performance liquid chromatography (HPLC). However, when dealing with complex mixtures, they often exhibit limited separation capabilities and peak tailing phenomena. To address this problem, two novel HPLC stationary phases based on polyamine macrocycles were developed. A trianglamine macrocyclic stationary phase (TRI-Sil) was first prepared using chlorinated silica gel as the support, which can effectively separate a variety of aromatic compounds, but with limited selectivity for positional isomers such as phenylenediamine. To further improve the separation selectivity, a polyamine-silica macrocyclic stationary phase (CPAM-Sil) was synthesized by introducing a branched-chain-containing monomer. Under optimized conditions, CPAM-Sil achieved baseline separation of phenylenediamine and phenylenediol positional isomers and improved the separation of terphenyl isomers, with favorable asymmetry factors and high column efficiency compared with the commercial C18 column. Molecular docking confirmed multiple interactions such as electrostatic interactions and hydrogen bonding between the polyamine macrocycle (CPAM) and analytes. The CPAM-Sil column also exhibited good reproducibility and stability, showing promising potential for industrial application in chromatographic separation.