Preparation of two amide-bonded stationary phases and comparative evaluation under mixed-mode chromatography.

In this work, the conventional reactions were used to functionalize the silica surface with amide and hydrocarbon chain groups affording two different mixed-mode stationary phases (Sil-amide-C11 and Sil-C12-amide). The prepared stationary phases were analyzed by elemental analysis and thermogravimetric analysis. The retention of benzene, phenol, pyridine, and aniline was investigated and compared with synthesized and commercial columns, and this led to prove the existence of different interactions on the synthesized stationary phases.

Preparation and evaluation a mixed-mode stationary phase with C and 2-methylindole for HPLC.

A modified C column (Silpr-2MI-C18) was prepared using 2-methylindole and C reagent. The extent of C hydrocarbon chain, conjugative rings and anion exchange site provided multiple retention mechanisms, including reversed-phase liquid chromatography (RPLC), π-π interaction, hydrophilic interaction liquid chromatography (HILIC) and anion exchange chromatography (AEC). The separation of protected amino acids was investigated on the commercial C and Silpr-2MI-C18 columns, while the chromatographic conditions, including methanol content and pH of the mobile phase, were studied.

Silica modification with 9-methylacridine and 9-undecylacridine as mixed-mode stationary phases in HPLC.

In this research, 9-methylacridine and 9-undecylacridine were synthesized through Bernthsen's reaction and well characterized using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). Two mixed-mode stationary phases were developed by functionalizing silica with 9-methylacridine and 9-undecylacridine. Then, two modified silicas were characterized by elemental analysis, thermogravimetric analysis (TGA), and fourier transform-infrared spectroscopy (FT-IR).