Personal Information

Hobbies: Graduate and Professional Student Federation

Favorite Place in Chapel Hill: Carrburritos (Carrboro)

Undergraduate Institution

Slurry Packing Investigations to Improve Capillary and Microfluidic Column Efficiency for Ultra-High Pressure Liquid Chromatography

Over the past decade, ultra-high pressure liquid chromatography (UHPLC) has grown to become a more common technique both commercially and in academic research. Originally developed in the Jorgenson lab, UHPLC allows for the use of pressures in excess of 20 kpsi to give sufficient flow rates in capillary columns containing sub-2 micron particles coated with stationary phase. [1] This is important because separation efficiency increases as particle size decreases; however, packing efficiency tends to decrease with this size reduction, commonly because of particle flocculation. [2] Extensive characterization of reverse-phase C18 columns packed with 1.0 μm non-porous silica particles and 1.5 μm porous bridged-ethyl hybrid (BEH) particles has been performed previously in the lab, with predicted theoretical performance achieved in both cases. [3-5] Porous particles are preferred due to their much larger specific surface area (SSA), and packing such stationary phase supports with decreasing diameters is a current focus in column development. Recently, work has been conducted in the Jorgenson lab to determine what slurry packing solvents would provide the most efficient packing for porous 0.9 μm particles. [6] Although columns packed with 0.9 μm particles in an acetone slurry have been found to perform as efficiently as theory predicts, the method is not completely reproducible, most likely due to particle aggregation. This problem is expected to increase as particle diameter decreases, so solving the issue of aggregation is necessary for the efficient packing of columns and microfluidic devices with sub-micron particles.

My proposed area for research in UHPLC involves the use of ionic surfactants to help prevent particle flocculation during the packing of capillary columns and on-chip microfluidic devices. Additionally, I plan to investigate the use of novel silica particle shapes as possible stationary phase supports for use in both HPLC and UHPLC for improved efficiency as well as reduced particle aggregation.