Preparation, chromatographic evaluation and comparison between linear peptide- and cyclopeptide-bonded stationary phases.

In this paper, linear and cyclic tetrapeptide bonded stationary phases, were synthesized by the solid-phase synthesis method. Each amino acid coupling step was monitored by the ninhydrin test using UV/visible spectrophotometry. The proposed materials were characterized by UV spectroscopy, Fourier transform infrared spectroscopy, elemental analysis and thermogravimetric analysis, which proved the successful immobilization of tetrapeptide on the silica support. The cyclopeptide stationary phase displayed mixed-mode behavior and had the size selectivity for polycyclic aromatic hydrocarbon such as anthracene, while the linear peptide stationary phase only exhibited typical hydrophilic interaction chromatography (HILIC) characteristics and was more hydrophilic under the same mobile phase condition. Retention behaviors of polar compounds on the two stationary phases were studied through varying column temperature, the water content, pH and ionic strength in mobile phase. Applications in the separation of the mixture of nucleosides, sulfa compounds, organic acids and isomers of substituted benzoic acid compounds were demonstrated.