Surface Modification of Superficially Porous Silica Particles with p-phenylenediamine using Diazonium Chemistry: A New Stationary Phase for Liquid Chromatography

Description:
Column technology continues to be an important area of research in the field of high-performance liquid chromatography (HPLC). Columns packed with materials that provide new selectivity and increased hydrolytic stability provide chromatographers with the means to analyze more diverse samples, increased flexibility in method development, and extended column lifetimes. We have synthesized a new stationary phase utilizing diazonium chemistry to anchor a polymeric-like phenylamine layer to the silica surface of superficially porous particles. The synthetic reaction parameters (e.g., reaction temperature, stirring speed, and rate of reagent addition) were optimized to generate a thin layer at the silica surface with a controlled surface coverage. This new material was characterized utilizing diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), elemental analysis (EA), and nitrogen sorption techniques (BET/BJH) for surface area and porosity measurements.
The phenylenediamine-modified silica particles were packed into an analytical HPLC column for chromatographic assessment using model compounds. The column showed an increased hydrolytic stability when compared with traditional silica modification procedures. For comparison purposes, the chromatographic behavior of the phenylenediamine-modified silica was compared to commercially available C18 and phenyl columns.

Speaker: Brandon Salazar - University at Buffalo