Chromatographic Regulation by the Building Blocks for Triazine Polymer-Based Core–Shell Stationary Phases

Two versions of reversed-phase/hydrophilic interaction mixed-mode core–shell stationary phases for high-performance liquid chromatography using porous organic polymers as the shell material were investigated. The stationary phase named SiO2@CTPCC-TPB using triazine-triphenylbenzene-based porous organic polymers as the shell material has been reported previously. To regulate chromatographic performance, heptazine–biphenyl moieties with fewer benzene rings and higher nitrogen content were used as organic building blocks to grow a porous shell on the surface of silica to acquire a core–shell stationary phase, namely, SiO2@CHPCy-DB. Various techniques were used to characterize the developed core–shell microsphere, and nonpolar/polar solutes were utilized as probes to investigate the chromatographic behavior of the stationary phase. The results revealed that SiO2@CHPCy-DB exhibited reversed-phase/hydrophilic interaction mixed-mode with multiple retention mechanisms. Meanwhile, the separation behavior of the two homemade columns and a commercial column was compared to assess the role of the building blocks in porous organic polymers in regulating and improving separation. The successful determination of drugs of abuse in urine via the SiO2@CHPCy-DB column indicated its potential for the determination of trace analytes in complex samples.