Preparation of a stationary phase with s-triazine ring embedded group for reversed phase high-performance LC.

This paper describes the synthesis and chromatographic evaluation of a new polar-embedded stationary phase, which utilized 2,4,6-trichloro-1,3,5-triazine as the spacer. The resulting materials were characterized by elemental analysis, IR, and solid-state (13)C NMR. Empirical test mixtures were utilized to evaluate the column, and showed that it had good performance for basic compounds and high selectivity for polyaromatic hydrocarbons. Moreover, the novel stationary phase has unique property, especially in the separation of "homologous alkaloids" from natural products.

Pore expansion of highly monodisperse phenylene-bridged organosilica spheres for chromatographic application.

Monodisperse phenylene-bridged organosilica spheres show great potential as chromatographic stationary phase. In this paper, the tunable particle size of monodisperse phenylene-bridged organosilica spheres were prepared by co-condensing different proportion of 1,4-bis(triethoxysilyl)benzene (1,4-BTEB) and tetraethylorthosilicate (TEOS), and then pore size was expanded by two-step post-synthesis hydrothermal treatments using N,N-dimethyldecylamine (DMDA)/dodecylamine (DDA) and tris-(hydroxymethyl)-aminomethane (TRIS) in turn. Phenylene-bridged organosilica spheres with particle size of 3.0-3.5microm and pore size of 85A were further surface modified by C(18) group and tested in reversed-phase high performance liquid chromatography (RP-HPLC). The primary chromatographic results demonstrated that C(18) bonded phenylene-bridged organosilica stationary phase has high retention and good chemical stability in the high pH mobile phase, which indicated that the phenylene-bridged organosilica can be used for HPLC packing supports.

Large-pore monodispersed mesoporous silica spheres: synthesis and application in HPLC.

Monodispersed mesoporous silica spheres (MMSS) with periodical large-pore size (up to 200 A) and uniform particle size (1-1.7 mum) have successfully been synthesized by utilizing a new kind of surfactant, and they also demonstrated great potential application in HPLC.

Phenylene-bridged hybrid spheres for high performance liquid chromatography.

Highly monodisperse 1,3-phenylene-bridged hybrid organosilica spheres (m-PHS) were synthesized by co-condensation of tetraethoxysilane (TEOS) and 1,3-bis(triethoxysilyl)benzene (1,3-BTEB) using dodecylamine (DDA) and cetyltrimethylammonium bromide (CTAB) as templates. In this method, three important factors are the surfactants, the ethanol-water volume ratio and the TEOS/1,3-BTEB molar ratio. Their effects on the spherical particle morphologies were investigated systematically to optimize the synthesis conditions. With the optimal method, m-PHS was prepared with uniform particles in a narrow range 1.8∼2.5 µm. Likewise, highly monodisperse 1,4-phenylene-bridged hybrid organosilica spheres (p-PHS) were synthesized from TEOS and 1,4-bis(triethoxysilyl)benzene (1,4-BTEB) to compare the chromatographic properties with m-PHS. Both two hybrid materials can be directly used for reversed-phase high-performance liquid chromatography (RP-HPLC), showing high column efficiency, and the m-PHS stationary phase exhibits a much longer retention time and better separation ability for some aromatic compounds.